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Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2017	Jan. 31, 2018	Jun. 30, 2017
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	FY
Trading Symbol	LAZ
Entity Registrant Name	LAZARD LTD
Entity Central Index Key	0001311370
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		129,766,091
Entity Public Float			$ 5,558,845,377
Subsidiaries of Lazard Ltd [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		11,271,442

Consolidated Statements of Financial Condition - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
ASSETS
Cash and cash equivalents	$ 1,483,836	$ 1,158,785
Deposits with banks and short-term investments	935,431	419,668
Cash deposited with clearing organizations and other segregated cash	35,539	29,030
Receivables (net of allowance for doubtful accounts of $23,746 and $16,386 at December 31, 2017 and 2016, respectively):
Fees	487,800	564,291
Customers and other	83,816	73,991
Total receivables, net	571,616	638,282
Investments	427,186	459,422
Property (net of accumulated amortization and depreciation of $317,827 and $286,001 at December 31, 2017 and 2016, respectively)	205,301	209,021
Goodwill and other intangible assets (net of accumulated amortization of $63,099 and $60,080 at December 31, 2017 and 2016, respectively)	391,364	382,024
Deferred tax assets	650,260	1,075,777
Other assets	228,144	184,499
Total Assets	4,928,677	4,556,508
Liabilities:
Deposits and other customer payables	992,338	472,283
Accrued compensation and benefits	593,781	541,588
Senior debt	1,190,383	1,188,600
Deferred tax liabilities	9,407	9,168
Other liabilities	573,588	537,446
Total Liabilities	3,669,772	3,262,695
Commitments and contingencies
Common stock:
Class A, par value $.01 per share (500,000,000 shares authorized; 129,766,091 shares issued at December 31, 2017 and 2016, including shares held by subsidiaries as indicated below)	1,298	1,298
Additional paid-in-capital	788,140	688,231
Retained earnings	1,080,413	1,134,186
Accumulated other comprehensive loss, net of tax	(232,518)	(314,222)
Stockholders' equity subtotal before common stock held by subsidiaries and Noncontrolling interests, total	1,637,333	1,509,493
Class A common stock held by subsidiaries, at cost (10,747,142 and 7,628,786 shares at December 31, 2017 and 2016, respectively)	(437,530)	(273,506)
Total Lazard Ltd Stockholders’ Equity	1,199,803	1,235,987
Noncontrolling interests	59,102	57,826
Total Stockholders’ Equity	1,258,905	1,293,813
Total Liabilities and Stockholders’ Equity	4,928,677	4,556,508
LTBP Trust [Member]
Liabilities:
Tax receivable agreement obligation	310,275	513,610
Series A Preferred Stock [Member]
Preferred stock:
Preferred stock
Series B Preferred Stock [Member]
Preferred stock:
Preferred stock

Consolidated Statements of Financial Condition (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Allowance for doubtful accounts receivables	$ 23,746	$ 16,386	$ 12,882	$ 23,540
Property, accumulated amortization and depreciation	317,827	286,001
Other intangible assets, accumulated amortization	$ 63,099	$ 60,080
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	15,000,000	15,000,000
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	129,766,091	129,766,091
Common stock held by subsidiaries, shares	10,747,142	7,628,786
Series A Preferred Stock [Member]
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0	7,921
Series B Preferred Stock [Member]
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0	0

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
REVENUE
Investment banking and other advisory fees	$ 1,385,536	$ 1,298,364	$ 1,276,096
Asset management fees	1,195,550	998,887	1,036,821
Interest income	7,144	5,233	5,286
Other	109,599	81,179	86,564
Total revenue	2,697,829	2,383,663	2,404,767
Interest expense	53,518	50,292	51,159
Net revenue	2,644,311	2,333,371	2,353,608
OPERATING EXPENSES
Compensation and benefits	1,512,873	1,340,543	1,319,746
Occupancy and equipment	124,842	109,305	109,867
Marketing and business development	89,205	83,202	81,541
Technology and information services	121,671	97,461	95,528
Professional services	47,932	45,512	49,529
Fund administration and outsourced services	71,305	63,421	61,363
Amortization and other acquisition-related costs	9,514	35,247	5,821
Provision (benefit) pursuant to tax receivable agreement	(202,546)		547,691
Other	44,069	41,219	99,142
Total operating expenses	1,818,865	1,815,910	2,370,228
OPERATING INCOME (LOSS)	825,446	517,461	(16,620)
Provision (benefit) for income taxes	565,599	123,769	(1,009,552)
NET INCOME	259,847	393,692	992,932
LESS - NET INCOME ATTRIBUTABLE TO NONCONTROLLING INTERESTS	6,264	5,994	6,559
NET INCOME ATTRIBUTABLE TO LAZARD LTD	$ 253,583	$ 387,698	$ 986,373
WEIGHTED AVERAGE SHARES OF COMMON STOCK OUTSTANDING:
Basic	121,573,442	124,770,401	125,366,272
Diluted	132,479,728	132,633,630	133,244,546
NET INCOME PER SHARE OF COMMON STOCK:
Basic	$ 2.09	$ 3.11	$ 7.87
Diluted	1.91	2.92	7.40
DIVIDENDS DECLARED PER SHARE OF COMMON STOCK	$ 2.81	$ 2.69	$ 2.35

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement Of Income And Comprehensive Income [Abstract]
NET INCOME	$ 259,847	$ 393,692	$ 992,932
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX:
Currency translation adjustments	71,669	(57,920)	(51,182)
Employee benefit plans:
Actuarial gain (loss) (net of tax expense (benefit) of $(3,507), $(5,205) and $5,644 for the years ended December 31, 2017, 2016 and 2015, respectively)	2,085	(24,473)	11,283
Adjustment for items reclassified to earnings (net of tax expense of $2,220, $1,757 and $1,507 for the years ended December 31, 2017, 2016 and 2015, respectively)	7,951	2,526	6,309
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX	81,705	(79,867)	(33,590)
COMPREHENSIVE INCOME	341,552	313,825	959,342
LESS - COMPREHENSIVE INCOME ATTRIBUTABLE TO NONCONTROLLING INTERESTS	6,265	5,993	6,559
COMPREHENSIVE INCOME ATTRIBUTABLE TO LAZARD LTD	$ 335,287	$ 307,832	$ 952,783

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement Of Income And Comprehensive Income [Abstract]
Tax expense (benefit) on actuarial gain (loss), employee benefit plans	$ (3,507)	$ (5,205)	$ 5,644
Tax expense, adjustment for items reclassified to earnings, employee benefit plans	$ 2,220	$ 1,757	$ 1,507

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 259,847	$ 393,692	$ 992,932
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization of property	31,498	33,264	32,785
Amortization of deferred expenses and share-based incentive compensation	359,381	341,825	320,472
Amortization and other acquisition-related costs	9,514	35,247	5,821
Deferred tax provision (benefit)	501,163	63,660	(1,100,785)
Provision (benefit) pursuant to tax receivable agreement	(202,546)		547,691
Loss on extinguishment of debt		3,148	60,219
Gain on acquisition of portion of business already owned		(12,668)
Gain on disposal of subsidiaries			(24,388)
(Increase) decrease in operating assets:
Deposits with banks and short-term investments	(430,388)	(44,278)	(207,373)
Cash deposited with clearing organizations and other segregated cash	(5,170)	5,767	6,909
Receivables-net	95,976	(156,129)	33,145
Investments	28,922	71,552	64,159
Other assets	(80,550)	(55,611)	(90,138)
Increase (decrease) in operating liabilities:
Deposits and other payables	428,826	(17,095)	225,008
Accrued compensation and benefits and other liabilities	18,969	(61,087)	20,839
Net cash provided by operating activities	1,015,442	601,287	887,296
CASH FLOWS FROM INVESTING ACTIVITIES:
Additions to property	(27,670)	(38,749)	(26,629)
Disposals of property	750	1,096	677
Net cash used in investing activities	(26,920)	(37,653)	(25,952)
Proceeds from:
Contributions from noncontrolling interests		93	275
Issuance of senior debt, net of expenses		296,757	396,272
Excess tax benefits from share-based incentive compensation		4,071	13,300
Other financing activities		24,484
Payments for:
Senior debt		(101,441)	(509,098)
Capital lease obligations	(7,337)	(1,619)	(1,826)
Distributions to noncontrolling interests	(5,193)	(2,111)	(16,296)
Payments under tax receivable agreement	(789)	(10,086)	(1,276)
Partial extinguishment of tax receivable agreement obligation			(42,222)
Purchase of Class A common stock	(306,741)	(300,217)	(172,772)
Class A common stock dividends	(341,450)	(336,138)	(290,684)
Settlement of vested share-based incentive compensation	(67,899)	(56,078)	(120,116)
Other financing activities	(10,984)	(4,667)	(2,361)
Net cash used in financing activities	(740,393)	(486,952)	(746,804)
EFFECT OF EXCHANGE RATE CHANGES ON CASH	76,922	(49,980)	(49,037)
NET INCREASE IN CASH AND CASH EQUIVALENTS	325,051	26,702	65,503
CASH AND CASH EQUIVALENTS—January 1	1,158,785	1,132,083	1,066,580
CASH AND CASH EQUIVALENTS—December 31	1,483,836	1,158,785	1,132,083
Cash paid during the year for:
Interest	49,601	46,262	45,359
Income taxes, net of refunds	$ 48,738	$ 72,420	$ 60,716

Consolidated Statements of Changes in Stockholders' Equity - USD ($)
$ in Thousands

Total

Common Stock [Member]

Additional Paid-In-Capital [Member]

Retained Earnings [Member]

Accumulated Other Comprehensive Income (Loss), Net of Tax [Member]

Class A Common Stock Held By Subsidiaries [Member]

Total Lazard Ltd Stockholders' Equity [Member]

Noncontrolling Interests [Member]

Series A Preferred Stock [Member]

Balance at Dec. 31, 2014

$ 770,057

$ 1,298

$ 702,800

$ 464,655

$ (200,766)

$ (261,243)

$ 706,744

$ 63,313

Balance (in shares) at Dec. 31, 2014

129,766,091

^[1]

7,450,745

7,921

Comprehensive income (loss):

Net income

992,932

986,373

6,559

Other comprehensive income (loss) - net of tax

(33,590)

Amortization of share-based incentive compensation

226,723

Dividend-equivalents

(2,361)

34,255

(36,616)

(2,361)

Class A common stock dividends

(290,684)

Purchase of Class A common stock

$ (172,772)

(172,772)

Purchase of Class A common stock (in shares)

3,438,789

Delivery of Class A common stock in connection with share-based incentive compensation and related tax benefit (expense)

$ (106,978)

(362,417)

$ 255,439

(106,978)

Delivery of Class A common stock in connection with shared-based incentive compensation and related tax benefit (expense) (in shares)

(6,608,837)

Business acquisitions and related equity transactions:

Delivery of Class A common stock and related tax benefit

(1,327)

$ 1,327

Delivery of Class A common stock and related tax benefit (in shares)

(27,316)

Distributions to noncontrolling interests, net

(16,021)

Balance at Dec. 31, 2015

1,367,306

$ 1,298

600,034

1,123,728

(234,356)

$ (177,249)

1,313,455

53,851

Balance (in shares) at Dec. 31, 2015

129,766,091

^[1]

4,253,381

7,921

Comprehensive income (loss):

Net income

393,692

387,698

5,994

Other comprehensive income (loss) - net of tax

(79,867)

(79,866)

(1)

Settlement of Series A preferred stock (in shares)

(7,921)

Amortization of share-based incentive compensation

261,462

Dividend-equivalents

(3,818)

37,284

(41,102)

(3,818)

Class A common stock dividends

(336,138)

Purchase of Class A common stock

$ (300,217)

(300,217)

Purchase of Class A common stock (in shares)

8,551,271

Delivery of Class A common stock in connection with share-based incentive compensation and related tax benefit (expense)

$ (55,630)

(224,201)

$ 168,571

(55,630)

Delivery of Class A common stock in connection with shared-based incentive compensation and related tax benefit (expense) (in shares)

(4,235,455)

Business acquisitions and related equity transactions:

Class A common stock issuable (including related amortization)

37,861

Delivery of Class A common stock and related tax benefit

1,621

(33,768)

$ 35,389

1,621

Delivery of Class A common stock and related tax benefit (in shares)

(940,411)

Distributions to noncontrolling interests, net

(2,018)

Other

9,559

Balance at Dec. 31, 2016

1,293,813

$ 1,298

688,231

1,134,186

(314,222)

$ (273,506)

1,235,987

57,826

Balance (in shares) at Dec. 31, 2016

129,766,091

^[1]

7,628,786

Adjustment for the cumulative effect on prior years from the adoption of new accounting guidance related to share-based incentive compensation at Dec. 31, 2016

81,544

Balance, as adjusted at Dec. 31, 2016

1,375,357

$ 1,298

688,231

1,215,730

(314,222)

$ (273,506)

1,317,531

57,826

Comprehensive income (loss):

Net income

259,847

253,583

6,264

Other comprehensive income (loss) - net of tax

81,705

81,704

Amortization of share-based incentive compensation

272,965

Dividend-equivalents

(5,908)

41,746

(47,654)

(5,908)

Class A common stock dividends

(341,450)

Purchase of Class A common stock

$ (306,741)

(306,741)

Purchase of Class A common stock (in shares)

6,956,097

Delivery of Class A common stock in connection with share-based incentive compensation and related tax benefit (expense)

$ (73,170)

(213,978)

$ 140,808

(73,170)

Delivery of Class A common stock in connection with shared-based incentive compensation and related tax benefit (expense) (in shares)

(3,790,267)

Business acquisitions and related equity transactions:

Class A common stock issuable (including related amortization)

508

Delivery of Class A common stock and related tax benefit

577

(1,332)

$ 1,909

577

Delivery of Class A common stock and related tax benefit (in shares)

(47,474)

Distributions to noncontrolling interests, net

(5,193)

Other

408

204

Balance at Dec. 31, 2017

$ 1,258,905

$ 1,298

$ 788,140

$ 1,080,413

$ (232,518)

$ (437,530)

$ 1,199,803

$ 59,102

Balance (in shares) at Dec. 31, 2017

129,766,091

^[1]

10,747,142

[1]	Includes 129,766,091 shares of the Company’s Class A common stock issued at December 31, 2015, 2016 and 2017, respectively.

Consolidated Statements of Changes in Stockholders' Equity (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Tax expense (benefit) related to the delivery of Class A common stock in connection with share-base incentive compensation	$ 5,271	$ (448)	$ (13,138)
Tax expense (benefit) on delivery of Class A common stock in connection with business acquisitions	$ 28	$ (1,074)
Common stock, shares issued	129,766,091	129,766,091
Class A Common Stock [Member]
Common stock, shares issued	129,766,091	129,766,091	129,766,091

Organization and Basis of Presentation

12 Months Ended

Dec. 31, 2017

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Organization and Basis of Presentation

1.	ORGANIZATION AND BASIS OF PRESENTATION

Organization

Lazard Ltd, a Bermuda holding company, and its subsidiaries (collectively referred to as “Lazard Ltd”, “Lazard”, “we” or the “Company”), including Lazard Ltd’s indirect investment in Lazard Group LLC, a Delaware limited liability company (collectively referred to, together with its subsidiaries, as “Lazard Group”), is one of the world’s preeminent financial advisory and asset management firms and has long specialized in crafting solutions to the complex financial and strategic challenges of our clients. We serve a diverse set of clients around the world, including corporations, governments, institutions, partnerships and individuals.

Lazard Ltd indirectly held 100% of all outstanding Lazard Group common membership interests as of December 31, 2017 and 2016. Lazard Ltd, through its control of the managing members of Lazard Group, controls Lazard Group, which is governed by an Amended and Restated Operating Agreement dated as of October 26, 2015, as amended (the “Operating Agreement”).

Lazard Ltd’s primary operating asset is its indirect ownership of the common membership interests of, and managing member interests in, Lazard Group, whose principal operating activities are included in two business segments:

•

Financial Advisory, which offers corporate, partnership, institutional, government, sovereign and individual clients across the globe a wide array of financial advisory services regarding mergers and acquisitions (“M&A”) and other strategic matters, restructurings, capital structure, capital raising, shareholder advisory, and various other financial matters, and

•

Asset Management, which offers a broad range of global investment solutions and investment management services in equity and fixed income strategies, asset allocation strategies, alternative investments and private equity funds to corporations, public funds, sovereign entities, endowments and foundations, labor funds, financial intermediaries and private clients.

In addition, we record selected other activities in our Corporate segment, including management of cash, investments, deferred tax assets, outstanding indebtedness, certain contingent obligations, and assets and liabilities associated with Lazard Group’s Paris-based subsidiary Lazard Frères Banque SA (“LFB”).

Basis of Presentation

The consolidated financial statements are prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”). The Company’s policy is to consolidate entities in which it has a controlling financial interest. The Company consolidates:

•

Voting interest entities (“VOEs”) where the Company holds a majority of the voting interest in such VOEs, and

•

Variable interest entities (“VIEs”) where the Company is the primary beneficiary having the power to direct the activities of the VIE that most significantly impact the VIE’s economic performance and the obligation to absorb losses of, or receive benefits from, the VIE that could be potentially significant to the VIE.

When the Company does not have a controlling interest in an entity, but exerts significant influence over such entity’s operating and financial decisions, the Company either (i) applies the equity method of accounting in which it records a proportionate share of the entity’s net earnings, or (ii) elects the option to measure at fair value. Intercompany transactions and balances have been eliminated.

The consolidated financial statements include Lazard Ltd, Lazard Group and Lazard Group’s principal operating subsidiaries: Lazard Frères & Co. LLC (“LFNY”), a New York limited liability company, along with its subsidiaries, including Lazard Asset Management LLC and its subsidiaries (collectively referred to as “LAM”); the French limited liability companies Compagnie Financière Lazard Frères SAS (“CFLF”) along with its subsidiaries, LFB and Lazard Frères Gestion SAS (“LFG”), and Maison Lazard SAS and its subsidiaries; and Lazard & Co., Limited (“LCL”), through Lazard & Co., Holdings Limited (“LCH”), an English private limited company, together with their jointly owned affiliates and subsidiaries.

Certain prior period amounts have been reclassified to conform to the current period presentation, specifically by including capital lease obligations, previously presented separately, in other liabilities on the consolidated statements of financial condition. In addition, see Note 20 for the recasting of geographic information.

Significant Accounting Policies

12 Months Ended

Dec. 31, 2017

Accounting Policies [Abstract]

Significant Accounting Policies

2.	SIGNIFICANT ACCOUNTING POLICIES

The accounting policies below relate to reported amounts and disclosures in the consolidated financial statements.

Foreign Currency Translation—The consolidated financial statements are presented in U.S. Dollars. Many of the Company’s non-U.S. subsidiaries have a functional currency (i.e., the currency in which operational activities are primarily conducted) that is other than the U.S. Dollar, generally the currency of the country in which such subsidiaries are domiciled. Such subsidiaries’ assets and liabilities are translated into U.S. Dollars at year-end exchange rates, while revenue and expenses are translated at average exchange rates during the year based on the daily closing exchange rates. Adjustments that result from translating amounts from a subsidiary’s functional currency to U.S. Dollars are reported in “accumulated other comprehensive income (loss), net of tax” (“AOCI”). Foreign currency remeasurement gains and losses on transactions in non-functional currencies are included on the consolidated statements of operations. Foreign currency remeasurement gains (losses), net of hedge transactions (see Note 7) amounted to $1,900, $(1,153) and $1,589 for the years ended December 31, 2017, 2016 and 2015, respectively, and are included in “revenue-other” on the respective consolidated statements of operations.

Use of Estimates—The preparation of consolidated financial statements in conformity with U.S. GAAP requires the use of management’s estimates. In preparing the consolidated financial statements, management makes estimates and assumptions regarding:

•

valuations of assets and liabilities requiring fair value estimates including, but not limited to, investments, derivatives, securities sold, not yet purchased and assumptions used to value pension and other post-retirement plans;

•

the adequacy of the allowance for doubtful accounts;

•

the realization of deferred tax assets and adequacy of tax reserves for uncertain tax positions;

•

the measurement of our tax receivable agreement obligation;

•

the outcome of litigation;

•

the carrying amount of goodwill and other intangible assets;

•

the amortization period of intangible assets;

•

the valuation of shares issued or issuable that contain transfer restrictions;

•

the vesting of share-based and other deferred compensation plan awards; and

•

other matters that affect the reported amounts and disclosure of contingencies in the consolidated financial statements.

Estimates, by their nature, are based on judgment and available information. Therefore, actual results could differ from those estimates and could have a material impact on the consolidated financial statements.

Cash and Cash Equivalents—The Company defines cash equivalents as short-term, highly liquid securities and cash deposits with original maturities of 90 days or less when purchased.

Deposits with Banks and Short-Term Investments—Represents LFB’s short-term deposits, including with the Banque de France and amounts placed by LFB in short-term, highly liquid securities, such as French government securities, with original maturities of 90 days or less when purchased. The level of these deposits and investments may be driven by the level of LFB customer and bank-related interest-bearing time and demand deposits (which can fluctuate significantly on a daily basis) and by changes in asset allocation.

Cash Deposited with Clearing Organizations and Other Segregated Cash—Primarily represents restricted cash deposits made by the Company, including those to satisfy the requirements of clearing organizations.

Allowance for Doubtful Accounts—We maintain an allowance for bad debts to provide for estimated losses relating to fees and customer receivables. We determine the adequacy of the allowance by estimating the probability of loss based on management’s analysis of the client’s creditworthiness and specifically reserve against exposures where we determine the receivables may be impaired, which may include situations where a fee is in dispute or litigation has commenced.

With respect to fees receivable from Financial Advisory activities, such receivables are generally deemed past due when they are outstanding 60 days from the date of invoice. However, some Financial Advisory transactions include specific contractual payment terms that may vary from one month to four years (as is the case for our interest-bearing financing receivables) following the invoice date or may be subject to court approval (as is the case with bankruptcy-related restructuring assignments). In such cases, receivables are deemed past due when payment is not received by the agreed-upon contractual date or the court approval date, respectively. Financial Advisory fee receivables past due in excess of 180 days are fully provided for unless there is evidence that the balance is collectable. Asset Management fees are deemed past due and fully provided for when such receivables are outstanding 12 months after the invoice date. Notwithstanding our policy for receivables past due, we specifically reserve against exposures relating to Financial Advisory and Asset Management fees where we determine receivables are impaired.

See Note 4 for additional information regarding receivables.

Investments—Investments in debt and marketable equity securities held either directly, or indirectly through asset management funds, at the Company’s broker-dealer subsidiaries are accounted for at fair value, with any increase or decrease in fair value recorded in earnings. Such amounts are reflected in “revenue-other” in the consolidated statements of operations.

Investments in debt and marketable equity securities held at the Company’s non broker-dealer subsidiaries are considered “trading” securities and are accounted for at fair value, with any increase or decrease in fair value reflected in “revenue-other” in the consolidated statements of operations.

Investments also include interests in alternative investment funds and private equity funds, each accounted for at fair value, as well as investments accounted for under the equity method of accounting. Any increases or decreases in the carrying value of those investments accounted for at fair value and the Company’s share of net income or losses pertaining to its equity method investments are reflected in “revenue-other” in the consolidated statements of operations.

Dividend income is reflected in “revenue-other” on the consolidated statements of operations. Interest income includes accretion or amortization of any discount or premium arising at acquisition of the related debt security. Securities transactions and the related revenue and expenses are recorded on a “trade date” basis.

See Notes 5 and 6 for additional information regarding the Company’s investments.

Property-net—Property is stated at cost or, in the case of property under capital leases, the present value of the future minimum lease payments, less accumulated depreciation and amortization. Buildings represent owned property and amounts recorded pursuant to capital leases (see Notes 8 and 12), with the related obligations recorded in “other liabilities” as capital lease obligations. Such buildings are depreciated on a straight-line basis over their estimated useful lives. Leasehold improvements are capitalized and are amortized over the lesser of the economic useful life of the improvement or the term of the lease. Depreciation of furniture and equipment, including computer hardware and software, is determined on a straight-line basis using estimated useful lives. Depreciation and amortization expense aggregating $31,498, $33,264 and $32,785 for the years ended December 31, 2017, 2016 and 2015, respectively, is included on the respective consolidated statements of operations in “occupancy and equipment” or “technology and information services”, depending on the nature of the underlying asset. Repairs and maintenance are expensed as incurred.

Goodwill and Other Intangible Assets—As goodwill has an indefinite life, it is required to be tested for impairment annually or more frequently if circumstances indicate impairment may have occurred. The Company performs a qualitative evaluation about whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount in lieu of actually calculating the fair value of the reporting unit.

The Company completed its annual goodwill review as of November 1, 2017, and determined that no impairment existed.

Intangible assets that are not deemed to have an indefinite life are amortized over their estimated useful lives and are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. The pattern of amortization reflects the timing of the realization of the economic benefits of such intangible assets. For acquired customer contracts, the period of realization is deemed to be the period when the related revenue is recognized. This analysis is performed by comparing the carrying value of the intangible asset being reviewed for impairment to the current and expected future cash flows expected to be generated from such asset on an undiscounted basis, including eventual disposition. An impairment loss would be measured for the amount by which the carrying amount of the intangible asset exceeds its fair value.

See Note 9 with respect to goodwill and other intangible assets.

Derivative Instruments—A derivative is typically defined as an instrument whose value is “derived” from underlying assets, indices or reference rates, such as a future, forward, swap, or option contract, or other financial instrument with similar characteristics. Derivative contracts often involve future commitments to exchange interest payment streams or currencies based on a notional or contractual amount (e.g., interest rate swaps or currency forwards) or to purchase or sell other financial instruments at specified terms on a specified date (e.g., options to buy or sell securities or currencies).

The Company enters into forward foreign currency exchange rate contracts, interest rate swaps, interest rate futures, total return swap contracts on various equity and debt indices and other derivative contracts to economically hedge exposures to fluctuations in currency exchange rates, interest rates and equity and debt prices. The Company reports its derivative instruments separately as assets and liabilities unless a legal right of set-off exists under a master netting agreement enforceable by law. The Company’s derivative instruments are recorded at their fair value, and are included in “other assets” and “other liabilities” on the consolidated statements of financial condition. Gains and losses on the Company’s derivative instruments are generally included in “interest income” and “interest expense”, respectively, or “revenue-other”, depending on the nature of the underlying item, in the consolidated statements of operations.

In addition to the derivative instruments described above, the Company records derivative liabilities relating to its obligations pertaining to Lazard Fund Interests (“LFI”) and other similar deferred compensation arrangements, the fair value of which is based on the value of the underlying investments, adjusted for estimated forfeitures, and is included in “accrued compensation and benefits” in the consolidated statements of financial condition. Changes in the fair value of the derivative liabilities are included in “compensation and benefits” in the consolidated statements of operations, the impact of which equally offsets the changes in the fair value of investments which are currently expected to be delivered upon settlement of LFI and other similar deferred compensation arrangements, which are reported in “revenue-other” in the consolidated statements of operations. For information regarding LFI and other similar deferred compensation arrangements, see Notes 5, 7 and 14.

Deposits and Other Customer Payables—Principally relates to LFB customer-related demand deposits, both interest-bearing and non-interest bearing.

Securities Sold, Not Yet Purchased—Securities sold, not yet purchased represents liabilities for securities sold for which payment has been received and the obligations to deliver such securities are included within “other liabilities” in the consolidated statements of financial condition. These securities are accounted for at fair value, with any increase or decrease in fair value recorded in earnings in accordance with standard securities industry practices. Such gains and losses are reflected in “revenue-other” in the consolidated statements of operations.

Contingent Consideration Liabilities —The contingent consideration liabilities of businesses acquired in a business combination are initially recorded at fair value and any change in the fair value is recognized in “amortization and other acquisition-related costs” in the consolidated statements of operations. The contingent consideration liability is included in “other liabilities” on the consolidated statements of financial condition.

Fair Value of Financial Assets and Liabilities—The majority of the Company’s financial assets and liabilities are recorded at fair value or at amounts that approximate fair value. Such assets and liabilities include cash and cash equivalents, deposits with banks and short-term investments, cash deposited with clearing organizations and other segregated cash, receivables, investments (excluding investments accounted for at amortized cost, interest-bearing deposits or using the equity method of accounting), derivative instruments, deposits and other customer payables.

Revenue Recognition

Investment Banking and Other Advisory Fees—Fees for M&A and Strategic Advisory services and Restructuring advisory services are recorded when (i) there is persuasive evidence of an arrangement with a client, (ii) fees are fixed or determinable, (iii) the agreed-upon services have been completed and delivered to the client or the transaction or events contemplated in the engagement letter are determined to be substantially completed, which is generally the date the related transactions are consummated and (iv) collection is reasonably assured. Expenses that are directly related to such transactions and billable to clients are deferred to match revenue recognition. “Investment banking and other advisory fees” on the Company’s consolidated statements of operations are presented net of client reimbursements of expenses. The amount of expenses reimbursed by clients for the years ended December 31, 2017, 2016 and 2015 are $17,793, $16,998 and $19,358, respectively.

Asset Management Fees—Asset Management fees are derived from fees for investment management and advisory services provided to clients. Revenue is recorded on an accrual basis primarily based on a percentage of client assets managed. Fees vary with the type of assets managed, with higher fees earned on equity assets, alternative investment (such as hedge funds) and private equity funds, and lower fees earned on fixed income and money market products.

In addition, the Company earns performance-based incentive fees on various investment products, including traditional products and alternative investment funds such as hedge funds and private equity funds.

For hedge funds, incentive fees are calculated based on a specified percentage of a fund’s net appreciation, in some cases in excess of established benchmarks or thresholds. The Company records incentive fees on traditional products and hedge funds at the end of the relevant performance measurement period, when potential uncertainties regarding the ultimate realizable amounts have been determined. The incentive fee measurement period is generally an annual period (unless an account terminates during the year). The incentive fees received at the end of the measurement period are not subject to reversal or payback. Incentive fees on hedge funds generally are subject to loss carryforward provisions in which losses incurred by the hedge funds in any year are applied against certain gains realized by the hedge funds in future periods before any incentive fees can be earned.

For private equity funds, incentive fees may be earned in the form of a “carried interest” if profits arising from realized investments exceed a specified threshold. Typically, such carried interest is ultimately calculated on a whole-fund basis and, therefore, clawback of carried interests during the life of the fund can occur. As a result, incentive fees earned on our private equity funds are not recognized until potential uncertainties regarding the ultimate realizable amounts have been determined, including any potential for clawback.

Receivables relating to asset management and incentive fees are reported in “fees receivable” on the consolidated statements of financial condition.

On January 1, 2018, the Company adopted new revenue recognition guidance. See Note 3.

Soft Dollar Arrangements—Certain entities within the Company’s Asset Management business obtain research and other services through commission-sharing arrangements with broker-dealers, which are also known as “soft dollar” arrangements. Consistent with the “soft dollar” safe harbor established by Section 28(e) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), the Asset Management business does not have any contractual obligation or arrangement requiring it to pay for research and other services obtained through soft dollar arrangements with brokers. Instead, the provider is obligated to pay for the services. Consequently, the Company does not incur any liability and does not accrue any expenses in connection with any research or other services obtained by the Asset Management business pursuant to such soft dollar arrangements. For the year ended December 31, 2017, the Company obtained research and other services through soft dollar arrangements valued at approximately $24,000. The use of soft dollars is limited by regulations in the European Union and the U.K. and, as such, the Company intends to directly pay a portion of the costs of such research and other services going forward.

Equity-Based Incentive Compensation Awards—Equity-based incentive compensation awards that do not require future service are expensed immediately. Equity-based compensation awards that require future service are amortized over the applicable vesting period, or requisite service period, based on the fair value of the Company’s Class A common stock on the date of grant. Compensation expense recognized for equity-based incentive compensation is determined based on the number of awards that in the Company’s estimate are considered probable of vesting (including as a result of any applicable performance conditions). Equity-based incentive compensation is recognized in “compensation and benefits” expense.

Cost Saving Initiatives and Staff Reductions—Charges associated with management-approved cost saving plans or staff reductions can include severance costs, charges to vacate facilities and contract cancellation costs. Severance costs are generally accrued on the date that employees are notified of their benefits and other costs are generally accrued as the Company ceases to use facilities or cancels contracts. The Company records severance-related liabilities in “accrued compensation and benefits” and other types of liabilities in “other liabilities” in the consolidated statements of financial condition.

Income Taxes—Lazard Ltd, through its subsidiaries, is subject to U.S. federal income taxes on all of its U.S. operating income, as well as on the portion of non-U.S. income attributable to its U.S. subsidiaries. In addition, Lazard Ltd, through its subsidiaries, is subject to state and local taxes on its income apportioned to various state and local jurisdictions. Outside the U.S., Lazard Group operates principally through subsidiary corporations that are subject to local income taxes in foreign jurisdictions. Lazard Group is also subject to Unincorporated Business Tax (“UBT”) attributable to its operations apportioned to New York City.

Deferred income taxes reflect the net tax effects of temporary differences between the financial reporting and tax basis of assets and liabilities and are measured using the enacted tax rates and laws that will be in effect when such differences are expected to reverse. Such temporary differences are reflected as deferred tax assets and deferred tax liabilities on the consolidated statements of financial condition. A deferred tax asset is recognized if it is more likely than not (defined as a likelihood of greater than 50%) that a tax benefit will be accepted by a taxing authority.

In assessing the realizability of deferred tax assets, management considers whether it is more likely than not that some portion or all of the deferred tax assets will be realized and, when necessary, a valuation allowance is established. The ultimate realization of the deferred tax assets is dependent upon the generation of future taxable income during the periods in which temporary differences become deductible. Management considers the following possible sources of taxable income when assessing the realization of deferred tax assets:

•

future reversals of existing taxable temporary differences;

•

future taxable income exclusive of reversing temporary differences and carryforwards;

•

taxable income in prior carryback years; and

•

tax-planning strategies.

The assessment regarding whether a valuation allowance is required or should be adjusted also considers all available information, including the following:

•

nature, frequency, magnitude and duration of any past losses and current operating results;

•

duration of statutory carryforward periods;

•

historical experience with tax attributes expiring unused; and

•

near-term and medium-term financial outlook.

The Company records tax positions taken or expected to be taken in a tax return based upon the Company’s estimates regarding the amount that is more likely than not to be realized or paid, including in connection with the resolution of any related appeals or other legal processes. Accordingly, the Company recognizes liabilities for certain unrecognized tax benefits based on the amounts that are more likely than not to be settled with the relevant taxing authority.

The Company recognizes interest and/or penalties related to unrecognized tax benefits in “provision (benefit) for income taxes”. See Note 16 for additional information relating to income taxes.

Recent Accounting Developments

12 Months Ended

Dec. 31, 2017

New Accounting Pronouncements And Changes In Accounting Principles [Abstract]

Recent Accounting Developments

3.	RECENT ACCOUNTING DEVELOPMENTS

Compensation—Stock Compensation: Improvements to Employee Share-Based Payment Accounting—In March 2016, the Financial Accounting Standards Board (the “FASB”) issued new guidance regarding share-based incentive compensation. The new guidance includes several amendments which affect various aspects of the accounting for share-based incentive compensation transactions, including the income tax consequences, estimation of forfeitures, effect on earnings per share, classification of awards as either equity or liabilities, and classification on the statement of cash flows. The Company adopted this new guidance on January 1, 2017. Since adoption, the new guidance has affected, and the Company expects that in future periods the new guidance will affect, the provision for income taxes for the delivery of stock under share-based incentive compensation arrangements, as well as the effective tax rate in the relevant periods, which could be material to the consolidated statements of operations and the classification of cash flows in the relevant periods. The inclusion of excess tax benefits as an operating activity within the statement of cash flows was adopted on a prospective basis, with prior periods unadjusted. Based on the new guidance, the excess tax benefits are no longer included as assumed proceeds in the calculation of earnings per share under the treasury stock method on a prospective basis. Upon adoption of the new guidance, the Company also recorded deferred tax assets of $81,544, net of a valuation allowance of $12,090, for previously unrecognized excess tax benefits (including tax benefits from dividends or dividend equivalents) on share-based incentive compensation arrangements, with an offsetting adjustment to retained earnings. With respect to forfeiture rates, the Company will continue to estimate the number of awards expected to be forfeited, rather than electing the option to account for forfeitures as they occur. See Note 16.

Revenue from Contracts with Customers—In May 2014, the FASB issued comprehensive new revenue recognition guidance. The guidance requires a company to recognize revenue when it transfers promised services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those services and requires enhanced disclosures. The guidance also changes the accounting for certain contract costs, including whether they may be offset against revenue in the consolidated statements of operations. On July 9, 2015, the FASB approved the deferral of the effective date of the new revenue guidance by one year to annual reporting periods beginning after December 15, 2017. The guidance may be adopted using a full retrospective approach or a modified cumulative effect approach. The Company adopted the revenue recognition guidance upon its effective date of January 1, 2018 using the modified cumulative effect approach. The Company’s adoption efforts included the identification of revenue within the scope of the guidance and the evaluation of revenue contracts.

The Company evaluated the potential impact of the new guidance including (i) the timing of revenue recognition for Financial Advisory and Asset Management fees and (ii) the presentation of certain contract costs. With respect to revenue recognition, the Company assessed the potential impact of the new guidance on the Company’s recognition of certain M&A and Restructuring Advisory fees (e.g., transaction completion, transaction announcement and retainer fees), including whether the Company’s fulfillment of its performance obligations under M&A and Restructuring Advisory engagement contracts would be deemed to occur over time, or at specific points in time, under the new guidance. Interpretive guidance on this particular topic was issued for comment by the Financial Reporting Executive Committee of the American Institute of Certified Public Accountants and is expected to be finalized during the first quarter of 2018. The Company considered the proposed guidance, and has concluded that M&A and Restructuring Advisory fees would typically be recognized over time as performance occurs, subject to constraints, using an appropriate measure of progress. In addition, Asset Management fees would typically be recognized over time as performance occurs, subject to constraints, using an appropriate measure of progress. Therefore, with regard to revenue recognition, it is expected that there will be no material impact to the Company’s financial statements.

With respect to the potential impact of the new guidance on the Company’s presentation of certain contract costs, the Company has concluded that the new guidance will result in the gross basis of presentation of certain contract costs that are currently presented net of certain items in revenues. The most significant changes with respect to presentation relate to (a) certain distribution costs within our Asset Management business and (b) certain reimbursable deal costs within our Financial Advisory business, both of which are currently presented net against revenues and will be presented as expenses on a gross basis under the new guidance. The impact to the Company’s financial statements is prospective and dependent on future activity levels. The Company currently expects that the prospective presentation will result in an increase to net revenue with a corresponding increase to operating expenses, and that there will be no material impact to net income.

Classification of Certain Cash Receipts and Cash Payments—In August and November 2016, the FASB issued updated guidance which clarifies how a company should classify certain cash receipts and cash payments on the statement of cash flows and clarifies that restricted cash should be included in the total of cash and cash equivalents on the statement of cash flows. The new guidance for both updates is effective for annual and interim periods beginning after December 15, 2017 and is to be applied on a retrospective basis. The Company adopted this new guidance on January 1, 2018 and its impact is not expected to be material to the Company’s financial statements.

Clarifying the Definition of a Business—In January 2017, the FASB issued updated guidance to clarify the definition of a business within the context of business combinations. The updated guidance requires that when substantially all of the fair value of the gross assets acquired (or disposed of) is concentrated in a single identifiable asset or a group of similar identifiable assets, the set is not a business. This updated guidance is expected to reduce the number of transactions that need to be further evaluated as business combinations. If further evaluation is necessary, the updated guidance will require that a business set include, at a minimum, an input and a substantive process that together significantly contribute to the ability to create output. The updated guidance will remove the evaluation of whether a market participant could replace missing elements. The new guidance is effective for annual and interim periods beginning after December 15, 2017 and is to be applied on a prospective basis. The Company adopted the new guidance on January 1, 2018 and it will be applied to business combinations on a prospective basis.

Compensation—Retirement Benefits—Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost—In March 2016, the FASB issued updated guidance on the presentation of net benefit cost in the statement of operations and the components eligible for capitalization. The new guidance requires that only the service cost component of net periodic pension cost and net periodic postretirement benefit cost be presented with other employee compensation costs in operating expenses, applied on a retrospective basis. The other components of net benefit cost, including amortization of prior service cost, and gains and losses from settlements and curtailments, are to be included in non-operating expenses. The new guidance also stipulates that only the service cost component of net benefit cost is eligible for capitalization, applied on a prospective basis. This new guidance is effective for annual and interim periods beginning after December 15, 2017. The Company adopted the new guidance on January 1, 2018 and no material impact is expected.

Compensation—Stock Compensation: Scope of Modification Accounting—In May 2017, the FASB issued updated guidance on modifications to share-based payment awards. The updated guidance requires entities to account for the effects of a modification to a share-based payment award unless the following are all the same immediately before and after the modification: (i) the fair value of the award, (ii) the vesting conditions of the award, and (iii) the classification of the award as an equity instrument or a liability instrument. This new guidance is effective for annual and interim periods beginning after December 15, 2017 and is to be applied on a prospective basis. The Company adopted the new guidance on January 1, 2018 and no material impact is expected because the Company’s accounting policy is already in compliance with the new guidance.

Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income—In February 2018, the FASB issued updated guidance on the tax effects of items in AOCI. Specifically, the new guidance will permit, but not require, a reclassification from AOCI to retained earnings for stranded tax effects resulting from the newly enacted federal corporate income tax rate under the Tax Cuts and Jobs Act of 2017 (see Note 16). The amount of the reclassification would be the difference between the historical corporate income tax rate and the newly enacted 21% corporate income tax rate. The new guidance is effective for annual and interim periods beginning after December 15, 2018, with an option to apply it in the period of adoption or on a retrospective basis for each period in which the effect of the change in the U.S. federal corporate income tax rate is recognized. Early adoption of the new guidance is permitted for public business entities for reporting periods for which financial statements have not yet been issued. The Company is currently evaluating the new guidance.

Leases—In February 2016, the FASB issued updated guidance for leases. The guidance requires a lessee to (i) recognize a right-of-use asset and a lease liability, initially measured at the present value of the lease payments, in the statement of financial condition, (ii) recognize a single lease cost, calculated so that the cost of the lease is allocated over the lease term on a generally straight-line basis and (iii) classify all cash payments within operating activities in the statement of cash flows. The new guidance is effective for annual and interim periods beginning after December 15, 2018, with early adoption permitted. The new guidance is to be applied on a modified retrospective basis. The Company is currently evaluating the new guidance.

Financial Instruments—Credit Losses: Measurement of Credit Losses on Financial Instruments—In June 2016, the FASB issued new guidance regarding the measurement of credit losses on financial instruments. The new guidance replaces the incurred loss impairment methodology in the current guidance with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to determine credit loss estimates. The new guidance is effective for annual and interim periods beginning after December 15, 2019 with early adoption permitted for fiscal years beginning after December 15, 2018. The Company is currently evaluating the new guidance.

Intangibles—Goodwill and Other: Simplifying the Test for Goodwill Impairment—In January 2017, the FASB issued updated guidance which eliminated Step 2 from the goodwill impairment test. Step 2 is the process of measuring a goodwill impairment loss by comparing the implied fair value of a reporting unit’s goodwill with the carrying amount of that goodwill. The new guidance requires entities to measure a goodwill impairment loss as the amount by which a reporting unit’s carrying value exceeds its fair value, limited to the carrying amount of goodwill. The FASB also eliminated the requirements for entities that have reporting units with zero or negative carrying amounts to perform a qualitative assessment for the goodwill impairment test. Instead, those entities would be required to disclose the amount of goodwill allocated to each reporting unit with a zero or negative carrying amount. The new guidance is effective for interim or annual goodwill impairment tests performed in fiscal years beginning after December 15, 2019, with early adoption permitted. The Company is currently evaluating the new guidance.

Receivables

12 Months Ended

Dec. 31, 2017

Receivables [Abstract]

Receivables

4.	RECEIVABLES

The Company’s receivables represent fee receivables, amounts due from customers and other receivables.

Receivables are stated net of an estimated allowance for doubtful accounts, for past due amounts and for specific accounts deemed uncollectible, which may include situations where a fee is in dispute.

Activity in the allowance for doubtful accounts for the years ended December 31, 2017, 2016 and 2015 was as follows:

	Year Ended December 31,
	2017			2016			2015
Beginning Balance	$	16,386		$	12,882		$	23,540
Bad debt expense, net of recoveries		15,419			10,055			3,125
Charge-offs, foreign currency translation and other adjustments		(8,059	)		(6,551	)		(13,783	)
Ending Balance	$	23,746		$	16,386		$	12,882

Bad debt expense, net of recoveries is included in “investment banking and other advisory fees” on the consolidated statements of operations.

At December 31, 2017 and 2016, the Company had receivables past due or deemed uncollectible of $34,865 and $22,212, respectively.

Of the Company’s fee receivables at December 31, 2017 and 2016, $80,536 and $76,133, respectively, represented interest-bearing financing receivables. Based upon our historical loss experience, the credit quality of the counterparties, and the lack of past due or uncollectible amounts, there was no allowance for doubtful accounts required at those dates related to such receivables.

The aggregate carrying amount of our non-interest bearing receivables of $491,080 and $562,149 at December 31, 2017 and 2016, respectively, approximates fair value.

- Definition

The entire disclosure for claims held for amounts due a entity, excluding financing receivables. Examples include, but are not limited to, trade accounts receivables, notes receivables, loans receivables. Includes disclosure for allowance for credit losses.

+ References + Details

Investments

12 Months Ended

Dec. 31, 2017

Investments Schedule [Abstract]

Investments

5.	INVESTMENTS

The Company’s investments and securities sold, not yet purchased, consist of the following at December 31, 2017 and 2016:

	December 31,
	2017		2016
Interest-bearing deposits	$	556	$	456
Debt		6		-
Equities		45,257		41,017
Funds:
Alternative investments (a)		20,993		32,441
Debt (a)		84,077		74,597
Equity (a)		199,618		188,268
Private equity		76,679		122,421
		381,367		417,727
Equity method		-		222
Total investments		427,186		459,422
Less:
Interest-bearing deposits		556		456
Equity method		-		222
Investments, at fair value	$	426,630	$	458,744
Securities sold, not yet purchased, at fair value (included in “other liabilities”)	$	7,338	$	4,482

(a)

Interests in alternative investment funds, debt funds and equity funds include investments with fair values of $11,213, $48,391 and $131,893, respectively, at December 31, 2017 and $13,080, $37,869 and $128,219, respectively, at December 31, 2016, held in order to satisfy the Company’s liability upon vesting of previously granted LFI and other similar deferred compensation arrangements. LFI represent grants by the Company to eligible employees of actual or notional interests in a number of Lazard-managed funds, subject to service-based vesting conditions (see Notes 7 and 14).

Interest-bearing deposits have original maturities of greater than three months but equal to or less than one year and are carried at cost that approximates fair value due to their short-term maturities.

Equities primarily consist of seed investments invested in marketable equity securities of large-, mid- and small-cap domestic, international and global companies held within separately managed accounts related to our Asset Management business.

Alternative investment funds primarily consist of interests in various Lazard-managed hedge funds, funds of funds and mutual funds.

Debt funds primarily consist of seed investments in funds related to our Asset Management business that invest in debt securities, amounts related to LFI discussed above and an investment in a Lazard-managed debt fund.

Equity funds primarily consist of seed investments in funds related to our Asset Management business that invest in equity securities, and amounts related to LFI discussed above.

Private equity investments include those owned by Lazard and those consolidated but not owned by Lazard. Private equity investments owned by Lazard are primarily comprised of investments in private equity funds. Such investments primarily include (i) Edgewater Growth Capital Partners III, L.P. (“EGCP III”), a fund primarily making equity and buyout investments in middle market companies, (ii) a fund targeting significant noncontrolling-stake investments in established private companies and (iii) until the second quarter of 2017, a mezzanine fund (the “Mezzanine Fund”), which invests in mezzanine debt of a diversified selection of small- to mid-cap European companies. Lazard sold its interest in the Mezzanine Fund in May 2017. In addition, in 2015, the Company disposed of its private equity business in Australia in a transaction with the management of the disposed business. Revenue of $24,388 relating to the disposal of the business primarily represents the realization of carried interest at fair value and is included in “revenue-other” on the consolidated statements of operations for the year ended December 31, 2015.

Private equity investments consolidated but not owned by Lazard relate to the economic interests that are owned by the management team and other investors in the Edgewater Funds (“Edgewater”).

During the years ended December 31, 2017, 2016 and 2015, the Company reported in “revenue-other” on its consolidated statements of operations net unrealized investment gains and losses pertaining to “trading” securities still held as of the reporting date as follows:

	Year Ended December 31,
	2017		2016		2015
Net unrealized investment gains (losses)	$	27,192	$	11,816	$	(19,681	)

Fair Value Measurements

12 Months Ended

Dec. 31, 2017

Fair Value Disclosures [Abstract]

Fair Value Measurements

6.	FAIR VALUE MEASUREMENTS

Fair Value Hierarchy of Investments and Certain Other Assets and Liabilities—Lazard categorizes its investments and certain other assets and liabilities recorded at fair value into a three-level fair value hierarchy as follows:

Level 1.

Assets and liabilities whose values are based on unadjusted quoted prices for identical assets or liabilities in an active market that Lazard has the ability to access.

Level 2.

Assets and liabilities whose values are based on (i) quoted prices for similar assets or liabilities in an active market, or quoted prices for identical or similar assets or liabilities in non-active markets, or (ii) inputs other than quoted prices that are directly observable or derived principally from, or corroborated by, market data.

Level 3.

Assets and liabilities whose values are based on prices or valuation techniques that require inputs that are both unobservable and significant to the overall fair value measurement. These inputs reflect our own assumptions about the assumptions a market participant would use in pricing the asset or liability. Items included in Level 3 include securities or other financial assets whose trading volume and level of activity have significantly decreased when compared with normal market activity and there is no longer sufficient frequency or volume to provide pricing information on an ongoing basis.

The fair value of equities is classified as Level 1 or Level 3 as follows: marketable equity securities are classified as Level 1 and are valued based on the last trade price on the primary exchange for that security as provided by external pricing services; equity securities in private companies are generally classified as Level 3.

The fair value of investments in alternative investment funds, debt funds and equity funds is classified as Level 1 when the fair values are primarily based on the publicly reported closing price for the fund.

The fair value of securities sold, not yet purchased, is classified as Level 1 when the fair values are based on unadjusted quoted prices in active markets.

The fair value of the contingent consideration liability is classified as Level 3 and the fair value of the liability is remeasured at each reporting period. The inputs used to derive the fair value of the contingent consideration include the application of probabilities when assessing certain performance thresholds for the relevant periods. Any change in the fair value is recognized in “amortization and other acquisition-related costs” in the consolidated statement of operations. Our business acquisitions may involve the potential payment of contingent consideration upon the achievement of certain performance thresholds. The contingent consideration liability is initially recorded at fair value of the contingent payments on the acquisition date and is included in “other liabilities” on the consolidated statements of financial condition. See Note 12.

The fair value of derivatives entered into by the Company is classified as Level 2 and is based on the values of the related underlying assets, indices or reference rates as follows: the fair value of forward foreign currency exchange rate contracts is a function of the spot rate and the interest rate differential of the two currencies from the trade date to settlement date; the fair value of total return swaps is based on the change in fair value of the related underlying equity security, financial instrument or index and a specified notional holding; the fair value of interest rate swaps is based on the interest rate yield curve; and the fair value of derivative liabilities related to LFI and other similar deferred compensation arrangements is based on the value of the underlying investments, adjusted for forfeitures. See Note 7.

Investments Measured at Net Asset Value (“NAV”)—As a practical expedient, the Company uses NAV or its equivalent to measure the fair value of certain investments. NAV is primarily determined based on information provided by external fund administrators. The Company’s investments valued at NAV as a practical expedient in (i) alternative investment funds, debt funds and equity funds are redeemable in the near term, and (ii) private equity funds are not redeemable in the near term as a result of redemption restrictions.

The following tables present, as of December 31, 2017 and 2016, the classification of (i) investments and certain other assets and liabilities measured at fair value on a recurring basis within the fair value hierarchy and (ii) investments measured at NAV or its equivalent as a practical expedient:

	December 31, 2017
	Level 1		Level 2		Level 3		NAV		Total
Assets:
Investments:
Debt	$	6	$	-	$	-	$	-	$	6
Equities		43,665		-		1,592		-		45,257
Funds:
Alternative investments		17,353		-		-		3,640		20,993
Debt		84,071		-		-		6		84,077
Equity		199,565		-		-		53		199,618
Private equity		-		-		-		76,679		76,679
Derivatives		-		3,732		-		-		3,732
Total	$	344,660	$	3,732	$	1,592	$	80,378	$	430,362
Liabilities:
Securities sold, not yet purchased	$	7,338	$	-	$	-	$	-	$	7,338
Contingent consideration liability		-		-		28,941		-		28,941
Derivatives		-		198,417		-		-		198,417
Total	$	7,338	$	198,417	$	28,941	$	-	$	234,696

	December 31, 2016
	Level 1		Level 2		Level 3		NAV		Total
Assets:
Investments:
Equities	$	39,509	$	-	$	1,508	$	-	$	41,017
Funds:
Alternative investments		25,316		-		-		7,125		32,441
Debt		74,591		-		-		6		74,597
Equity		188,229		-		-		39		188,268
Private equity		-		-		-		122,421		122,421
Derivatives		-		1,993		-		-		1,993
Total	$	327,645	$	1,993	$	1,508	$	129,591	$	460,737
Liabilities:
Securities sold, not yet purchased	$	4,482	$	-	$	-	$	-	$	4,482
Contingent consideration liability		-		-		22,608		-		22,608
Derivatives		-		182,223		-		-		182,223
Total	$	4,482	$	182,223	$	22,608	$	-	$	209,313

The following tables provide a summary of changes in fair value of the Company’s Level 3 assets and liabilities for the years ended December 31, 2017, 2016 and 2015:

	Year Ended December 31, 2017
	Beginning Balance		Net Unrealized/ Realized Gains/Losses Included In Earnings (a)		Purchases/ Acquisitions		Sales/ Dispositions/ Settlements			Foreign Currency Translation Adjustments		Ending Balance
Assets:
Investments:
Equities	$	1,508	$	14	$	1,661	$	(1,669	)	$	78	$	1,592
Total Level 3 Assets	$	1,508	$	14	$	1,661	$	(1,669	)	$	78	$	1,592

Liabilities:
Contingent consideration liability	$	22,608	$	6,582	$	-	$	(249	)	$	-	$	28,941
Total Level 3 Liabilities	$	22,608	$	6,582	$	-	$	(249	)	$	-	$	28,941

	Year Ended December 31, 2016
	Beginning Balance		Net Unrealized/ Realized Gains/Losses Included In Earnings (a)		Purchases/ Acquisitions		Sales/ Dispositions/ Settlements			Foreign Currency Translation Adjustments			Ending Balance
Assets:
Investments:
Equities	$	1,276	$	248	$	-	$	-		$	(16	)	$	1,508
Total Level 3 Assets	$	1,276	$	248	$	-	$	-		$	(16	)	$	1,508

Liabilities:
Contingent consideration liability	$	-	$	32,725	$	19,950	$	(30,067	)	$	-		$	22,608
Total Level 3 Liabilities	$	-	$	32,725	$	19,950	$	(30,067	)	$	-		$	22,608

	Year Ended December 31, 2015
	Beginning Balance		Net Unrealized/ Realized Gains/Losses Included In Earnings (a)		Purchases/ Acquisitions		Sales/ Dispositions/ Settlements		Foreign Currency Translation Adjustments			Ending Balance
Assets:
Investments:
Equities	$	1,315	$	14	$	-	$	-	$	(53	)	$	1,276
Total Level 3 Assets	$	1,315	$	14	$	-	$	-	$	(53	)	$	1,276

(a)

Earnings recorded in “other revenue” for investments in equities for the years ended December 31, 2017, 2016 and 2015 include net unrealized gains of $12, $243 and $14, respectively. Earnings recorded in “amortization and other acquisition-related costs” for the contingent consideration liability for the years ended December 31, 2017 and 2016 include unrealized losses of $6,582 and $2,658, respectively, and, for the year ended December 31, 2016, realized losses of $30,067 due to the change in the fair value of contingent consideration associated with the Edgewater business acquisition.

There were no transfers between any of the Level 1, 2 and 3 categories in the fair value measurement hierarchy during the years ended December 31, 2017 and 2016.

Financial Instruments Not Measured at Fair Value—The tables below present the carrying value, fair value and fair value hierarchy category of certain financial instruments as of December 31, 2017 and 2016 that are not measured at fair value in the Company’s consolidated statement of financial condition, and excludes certain financial instruments such as equity method investments.

	December 31, 2017
			Fair Value Measurements Using:
	Carrying Value		Fair Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Financial Assets:
Cash and cash equivalents	$	1,483,836	$	1,483,836	$	1,483,836	$	-	$	-
Deposits with banks and short-term investments		935,431		935,431		935,431		-		-
Cash deposited with clearing organizations and other segregated cash		35,539		35,539		35,539		-		-
Interest-bearing financing receivables		80,536		82,492		-		-		82,492
Interest-bearing deposits (included within investments)		556		556		556		-		-
Financial Liabilities:
Deposits and other customer payables	$	992,338	$	992,338	$	992,338	$	-	$	-
Senior debt		1,190,383		1,230,254		-		1,230,254		-

	December 31, 2016
			Fair Value Measurements Using:
	Carrying Value		Fair Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Financial Assets:
Cash and cash equivalents	$	1,158,785	$	1,158,785	$	1,158,785	$	-	$	-
Deposits with banks and short-term investments		419,668		419,668		419,668		-		-
Cash deposited with clearing organizations and other segregated cash		29,030		29,030		29,030		-		-
Interest-bearing financing receivables		76,133		78,072		-		-		78,072
Interest-bearing deposits (included within investments)		456		456		456		-		-
Financial Liabilities:
Deposits and other customer payables	$	472,283	$	472,283	$	472,283	$	-	$	-
Senior debt		1,188,600		1,204,171		-		1,204,171		-

Cash and cash equivalents are carried at either cost or amortized cost that approximates fair value due to their short-term maturities.

The carrying value of deposits with banks and short-term investments, and cash deposited with clearing organizations and other segregated cash, approximates fair value because of the relatively short period of time between their origination and expected maturity.

Fair values of interest-bearing financing receivables were generally determined by discounting both principal and interest cash flows expected to be collected, using a discount rate approximating current market interest rates for comparable financial instruments and based on unobservable inputs.

The carrying value of deposits and other customer payables and investments accounted for at amortized cost, such as interest-bearing deposits, approximate fair value due to their short-term nature.

The Company’s senior debt is carried at historical amounts. The fair value of the Company’s senior debt is based on market quotations.

The following tables present, at December 31, 2017 and 2016, certain investments that are valued using NAV or its equivalent as a practical expedient in determining fair value:

December 31, 2017

Estimated Liquidation Period of

Investments Not Redeemable

Investments

Redeemable

Fair Value

Unfunded

Commitments

% of

Fair Value

Not

Redeemable

5 Years

5-10

Years

Thereafter

Redemption

Frequency

Redemption

Notice Period

Alternative investment funds:

Hedge funds

2,517

(a)

<30-60 days

Funds of funds

528

(b)

<30-90 days

Other

595

(c)

<30-60 days

Debt funds

(d)

30 days

Equity funds

(e)

<30-90 days

Private equity funds:

Equity growth

76,679

10,300

(f)

100

Total

80,378

10,300

(a)	weekly (3%), monthly (5%) and quarterly (92%)

(b)	monthly (97%) and quarterly (3%)

(c)	daily (6%) and monthly (94%)

(d)	daily (100%)

(e)	daily (18%), monthly (50%) and quarterly (32%)

(f)	Unfunded commitments to private equity investments consolidated but not owned by Lazard of $5,902 are excluded. Such commitments are required to be funded by capital contributions from noncontrolling interest holders.

December 31, 2016

Estimated Liquidation Period of

Investments Not Redeemable

Investments

Redeemable

Fair Value

Unfunded

Commitments

% of

Fair Value

Not

Redeemable

5 Years

5-10

Years

Thereafter

Redemption

Frequency

Redemption

Notice Period

Alternative investment funds:

Hedge funds

6,190

(a)

<30-60 days

Funds of funds

492

(b)

<30-90 days

Other

443

(c)

<30-60 days

Debt funds

(d)

30 days

Equity funds

(e)

<30-90 days

Private equity funds:

Equity growth

90,824

9,183

(f)

100

Mezzanine debt

31,597

100

Total

129,591

9,183

(a)	weekly (73%), monthly (2%) and quarterly (25%)

(b)	monthly (98%) and quarterly (2%)

(c)	daily (7%) and monthly (93%)

(d)	daily (100%)

(e)	daily (19%), monthly (50%) and quarterly (31%)

(f)	Unfunded commitments to private equity investments consolidated but not owned by Lazard of $6,886 are excluded. Such commitments are required to be funded by capital contributions from noncontrolling interest holders.

Investment Capital Funding Commitments—At December 31, 2017, the Company’s maximum unfunded commitments for capital contributions to investment funds primarily arose from commitments to EGCP III, which amounted to $8,613. The investment period for EGCP III ended on October 12, 2016, after which point the Company’s obligation to fund capital contributions for new investments in EGCP III expired. The Company remains obligated until October 12, 2023 (or any earlier liquidation of EGCP III) to make capital contributions necessary to fund follow-on investments and to pay for fund expenses.

Derivatives

12 Months Ended

Dec. 31, 2017

Derivative Instruments And Hedging Activities Disclosure [Abstract]

Derivatives

7.	DERIVATIVES

The table below presents the fair value of the Company’s derivative instruments reported within “other assets” and “other liabilities” and the fair value of the Company’s derivative liabilities relating to its obligations pertaining to LFI and other similar deferred compensation arrangements reported within “accrued compensation and benefits” (see Note 14) on the accompanying consolidated statements of financial condition as of December 31, 2017 and 2016:

	December 31,
	2017		2016
Derivative Assets:
Forward foreign currency exchange rate contracts	$	3,314	$	1,993
Total return swaps and other (a)		418		-
	$	3,732	$	1,993
Derivative Liabilities:
Forward foreign currency exchange rate contracts	$	4,846	$	2,792
Total return swaps and other (a)		11,270		9,043
LFI and other similar deferred compensation arrangements		182,301		170,388
	$	198,417	$	182,223

(a)

For total return swaps, amounts represent the netting of gross derivative assets and liabilities of $469 and $11,321 as of December 31, 2017, respectively, and $357 and $9,400 as of December 31, 2016, respectively, for contracts with the same counterparty under legally enforceable master netting agreements. Such amounts are recorded “net” in “other assets”, with receivables for net cash collateral under such contracts of $17,616 and $16,996 as of December 31, 2017 and 2016, respectively.

Net gains (losses) with respect to derivative instruments (predominantly reflected in “revenue-other”) and the Company’s derivative liabilities relating to its obligations pertaining to LFI and other similar deferred compensation arrangements (included in “compensation and benefits” expense) as reflected on the accompanying consolidated statements of operations for the years ended December 31, 2017, 2016 and 2015, were as follows:

	Year Ended December 31,
	2017			2016			2015
Forward foreign currency exchange rate contracts	$	(9,144	)	$	(2,253	)	$	15,773
LFI and other similar deferred compensation arrangements		(23,526	)		(3,318	)		3,827
Total return swaps and other		(15,709	)		(4,636	)		3,860
Total	$	(48,379	)	$	(10,207	)	$	23,460

Property

12 Months Ended

Dec. 31, 2017

Property Plant And Equipment [Abstract]

Property

PROPERTY

At December 31, 2017 and 2016, property consisted of the following:

	Estimated
	Depreciable		December 31,
	Life in Years		2017		2016
Buildings		33	$	151,912	$	132,821
Leasehold improvements	3-20			173,102		175,810
Furniture and equipment	3-10			183,541		172,353
Construction in progress				14,573		14,038
Total				523,128		495,022
Less - Accumulated depreciation and amortization				317,827		286,001
Property			$	205,301	$	209,021

Goodwill and Other Intangible Assets

12 Months Ended

Dec. 31, 2017

Goodwill And Intangible Assets Disclosure [Abstract]

Goodwill and Other Intangible Assets

9.	GOODWILL AND OTHER INTANGIBLE ASSETS

The components of goodwill and other intangible assets at December 31, 2017 and 2016 are presented below:

	December 31,
	2017		2016
Goodwill	$	385,292	$	373,117
Other intangible assets (net of accumulated amortization)		6,072		8,907
	$	391,364	$	382,024

At December 31, 2017 and 2016, goodwill of $320,751 and $308,576, respectively, was attributable to the Company’s Financial Advisory segment and, at each such respective date, $64,541 of goodwill was attributable to the Company’s Asset Management segment.

Changes in the carrying amount of goodwill for the years ended December 31, 2017, 2016 and 2015 are as follows:

	Year Ended December 31,
	2017		2016			2015
Balance, January 1	$	373,117	$	320,761		$	335,402
Business acquisitions		-		54,631			-
Foreign currency translation adjustments		12,175		(2,275	)		(14,641	)
Balance, December 31	$	385,292	$	373,117		$	320,761

All changes in the carrying amount of goodwill for the years ended December 31, 2017, 2016 and 2015 are attributable to the Company’s Financial Advisory segment.

The Company evaluates goodwill for impairment annually or more frequently if circumstances indicate that impairment may have occurred. Pursuant to the Company’s goodwill impairment review for the years ended December 31, 2017, 2016 and 2015, the Company determined that no impairment existed.

The gross cost and accumulated amortization of other intangible assets as of December 31, 2017 and 2016, by major intangible asset category, are as follows:

	December 31, 2017						December 31, 2016
	Gross Cost		Accumulated Amortization		Net Carrying Amount		Gross Cost		Accumulated Amortization		Net Carrying Amount
Success/incentive fees	$	35,422	$	29,723	$	5,699	$	35,259	$	26,984	$	8,275
Management fees, customer relationships and non-compete agreements		33,749		33,376		373		33,728		33,096		632
	$	69,171	$	63,099	$	6,072	$	68,987	$	60,080	$	8,907

Amortization expense of intangible assets, included in “amortization and other acquisition-related costs” in the consolidated statements of operations, for the years ended December 31, 2017, 2016 and 2015 was $2,932, $2,522 and $5,821, respectively. Estimated future amortization expense is as follows:

Year Ending December 31,	Amortization Expense (a)
2018	$	2,941
2019		1,577
2020		1,554
Total amortization expense	$	6,072

(a)	Approximately 35% of intangible asset amortization is attributable to a noncontrolling interest.

- Definition

The entire disclosure for the aggregate amount of goodwill and a description of intangible assets, which may include (a) for amortizable intangible assets (also referred to as finite-lived intangible assets), the carrying amount, the amount of any significant residual value, and the weighted-average amortization period, (b) for intangible assets not subject to amortization (also referred to as indefinite-lived intangible assets), the carrying amount, and (c) the amount of research and development assets acquired and written off in the period, including the line item in the income statement in which the amounts written off are aggregated, if not readily apparent from the income statement. Also discloses (a) for amortizable intangibles assets in total and by major class, the gross carrying amount and accumulated amortization, the total amortization expense for the period, and the estimated aggregate amortization expense for each of the five succeeding fiscal years, (b) for intangible assets not subject to amortization the carrying amount in total and by major class, and (c) for goodwill, in total and for each reportable segment, the changes in the carrying amount of goodwill during the period (including the aggregate amount of goodwill acquired, the aggregate amount of impairment losses recognized, and the amount of goodwill included in the gain (loss) on disposal of a reporting unit). If any part of goodwill has not been allocated to a reportable segment, discloses the unallocated amount and the reasons for not allocating. For each impairment loss recognized related to an intangible asset (excluding goodwill), discloses: (a) a description of the impaired intangible asset and the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method for determining fair value, (c) the caption in the income statement or the statement of activities in which the impairment loss is aggregated, and (d) the segment in which the impaired intangible asset is reported. For each goodwill impairment loss recognized, discloses: (a) a description of the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method of determining the fair value of the associated reporting unit, and (c) if a recognized impairment loss is an estimate not finalized and the reasons why the estimate is not final. May also disclose the nature and amount of any significant adjustments made to a previous estimate of an impairment loss.

+ References + Details

Other Assets and Other Liabilities

12 Months Ended

Dec. 31, 2017

Text Block [Abstract]

Other Assets and Other Liabilities

10.	OTHER ASSETS AND OTHER LIABILITIES

The following table sets forth the Company’s other assets, by type, as of December 31, 2017 and 2016:

	December 31,
	2017		2016
Current tax receivables and other taxes	$	38,804	$	31,767
Prepaid compensation (see Note 14)		60,355		49,650
Other advances and prepayments		56,595		35,706
Other		72,390		67,376
Total	$	228,144	$	184,499

The following table sets forth the Company’s other liabilities, by type, as of December 31, 2017 and 2016:

	December 31,
	2017		2016
Accrued expenses	$	155,551	$	124,721
Current income taxes and other taxes		123,548		99,278
Employee benefit-related liabilities		69,201		84,703
Deferred lease incentives		85,028		84,287
Unclaimed funds at LFB		14,962		24,997
Deferred revenue		45,390		35,717
Contingent consideration liability		28,941		22,608
Securities sold, not yet purchased		7,338		4,482
Other		43,629		56,653
Total	$	573,588	$	537,446

Senior Debt

12 Months Ended

Dec. 31, 2017

Debt Disclosure [Abstract]

Senior Debt

11.	SENIOR DEBT

Senior debt is comprised of the following as of December 31, 2017 and 2016:

							Outstanding as of
	Initial			Annual			December 31, 2017						December 31, 2016
	Principal Amount		Maturity Date	Interest Rate(b)			Principal		Unamortized Debt Costs		Carrying Value		Principal		Unamortized Debt Costs		Carrying Value
Lazard Group 2020 Senior Notes	$	500,000	11/14/20		4.25	%	$	500,000	$	2,647	$	497,353	$	500,000	$	3,569	$	496,431
Lazard Group 2025 Senior Notes (a)		400,000	2/13/25		3.75	%		400,000		3,361		396,639		400,000		3,833		396,167
Lazard Group 2027 Senior Notes (a)		300,000	3/1/27		3.625	%		300,000		3,609		296,391		300,000		3,998		296,002
Total							$	1,200,000	$	9,617	$	1,190,383	$	1,200,000	$	11,400	$	1,188,600

(a)

During November 2016, Lazard Group completed an offering of $300,000 aggregate principal amount of 3.625% senior notes due 2027 (the “2027 Notes”). Interest on the 2027 Notes is payable semi-annually on March 1 and September 1 of each year, beginning March 1, 2017. Lazard Group used a portion of the net proceeds of the 2027 Notes to redeem or otherwise retire all $98,350 of the 6.85% senior notes due June 2017 (the “2017 Notes”), which, including the recognition of unamortized issuance costs, resulted in a loss on debt extinguishment of $3,148. Such loss on debt extinguishment was recorded in “operating expenses—other” on the consolidated statement of operations for the year ended December 31, 2016.

During February 2015, Lazard Group completed an offering of $400,000 aggregate principal amount of 3.75% senior notes due 2025 (the “2025 Notes”). Interest on the 2025 Notes is payable semi-annually on March 1 and September 1 of each year. Lazard Group used the net proceeds of the 2025 Notes, together with cash on hand, to redeem or otherwise retire $450,000 of the 2017 Notes, which, including the recognition of unamortized issuance costs, resulted in a loss on debt extinguishment of $60,219. Such loss on debt extinguishment was recorded in “operating expenses—other” on the consolidated statement of operations for the year ended December 31, 2015.

(b)

The effective interest rates of Lazard Group’s 4.25% senior notes due November 14, 2020 (the “2020 Notes”), the 2025 Notes and the 2027 Notes are 4.43%, 3.87% and 3.76%, respectively.

On September 25, 2015, Lazard Group entered into an Amended and Restated Credit Agreement for a five-year $150,000 senior revolving credit facility with a group of lenders (the “Amended and Restated Credit Agreement”), which expires in September 2020. The Amended and Restated Credit Agreement amended and restated the previous credit agreement dated September 25, 2012. Borrowings under the Amended and Restated Credit Agreement generally will bear interest at LIBOR plus an applicable margin for specific interest periods determined based on Lazard Group’s highest credit rating from an internationally recognized credit agency. At December 31, 2017 and 2016, no amounts were outstanding under the Amended and Restated Credit Agreement.

The Amended and Restated Credit Agreement, the indenture and the supplemental indentures relating to Lazard Group’s senior notes contain certain covenants, events of default and other customary provisions, including a customary make-whole provision in the event of early redemption, where applicable. As of December 31, 2017, the Company was in compliance with such provisions. All of the Company’s senior debt obligations are unsecured.

Debt maturities relating to senior borrowings outstanding at December 31, 2017 for each of the five years in the period ending December 31, 2022 and thereafter are set forth in the table below.

Year Ending December 31,
2018 - 2019	$	-
2020		500,000
2021 - 2022		-
Thereafter		700,000
Total	$	1,200,000

The Company’s senior debt at December 31, 2017 and 2016 is carried at historical amounts. See Note 6 for information regarding the fair value and fair value hierarchy category of the Company’s senior debt.

As of December 31, 2017, the Company had approximately $169,000 in unused lines of credit available to it, including the credit facility provided under the Amended and Restated Credit Agreement, and unused lines of credit available to LFB of approximately $18,000 (at December 31, 2017 exchange rates).

Commitments and Contingencies

12 Months Ended

Dec. 31, 2017

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

12.	COMMITMENTS AND CONTINGENCIES

Leases—The Company leases office space and equipment under non-cancelable lease agreements, which expire on various dates through 2033.

Operating lease agreements, in addition to base rentals, generally are subject to escalation provisions based on certain costs incurred by the landlord. For the years ended December 31, 2017, 2016 and 2015, aggregate rental expense relating to operating leases amounted to $84,632, $76,704 and $79,549, respectively, and is included in “occupancy and equipment” or “technology and information services” on the consolidated statements of operations, depending on the nature of the underlying asset. The Company also subleases office space under agreements which expire on various dates through 2022. Sublease income from such agreements was $7,659, $7,858 and $9,587 for the years ended December 31, 2017, 2016 and 2015, respectively, which includes sublease income of $1,281 from an affiliate of LMDC Holdings LLC (“LMDC Holdings”) for the year ended December 2015.

Capital lease obligations recorded under sale/leaseback transactions were paid in 2017. Such obligations were collateralized primarily by certain buildings with a net book value of approximately $13,538 at December 31, 2016. The net book value of all assets recorded under capital leases aggregated $13,628 at December 31, 2016.

At December 31, 2017, minimum rental commitments under non-cancelable operating leases, net of sublease income, are approximately as follows:


Year Ending December 31,
2018	$	83,851
2019		73,889
2020		69,845
2021		67,118
2022		56,268
Thereafter		442,438
Total minimum lease payments		793,409
Less sublease proceeds		36,141
Net lease payments	$	757,268

Guarantees—In the normal course of business, LFB provides indemnifications to third parties to protect them in the event of non-performance by its clients. At December 31, 2017, LFB had $2,995 of such indemnifications and held $2,995 of collateral/counter-guarantees to secure these commitments. The Company believes the likelihood of loss with respect to these indemnities is remote. Accordingly, no liability is recorded in the consolidated statement of financial condition.

Business Acquisitions—For businesses acquired in 2016, the remaining consideration consists of (i) previously paid one-time cash payments, 60,817 shares of Class A common stock subject to non-compete provisions and non-contingent interests exchangeable into 204,651 shares of Class A common stock, and (ii) up to 810,742 additional shares of Class A common stock that are subject to certain performance thresholds. As of December 31, 2017, none of the contingent shares had been earned.

Other Commitments—The Company has various other contractual commitments arising in the ordinary course of business. In addition, from time to time, each of LFB and LFNY may enter into underwriting commitments in which it will participate as an underwriter. At December 31, 2017, LFB and LFNY had no such underwriting commitments.

See Notes 6 and 15 for information regarding commitments relating to investment capital funding commitments and obligations to fund our pension plans, respectively.

In the opinion of management, the fulfillment of the commitments described herein will not have a material adverse effect on the Company’s consolidated financial position or results of operations.

Legal—The Company is involved from time to time in judicial, regulatory and arbitration proceedings and inquiries concerning matters arising in connection with the conduct of our businesses, including proceedings initiated by former employees alleging wrongful termination. The Company reviews such matters on a case-by-case basis and establishes any required accrual if a loss is probable and the amount of such loss can be reasonably estimated. The Company experiences significant variation in its revenue and earnings on a quarterly basis. Accordingly, the results of any pending matter or matters could be significant when compared to the Company’s earnings in any particular fiscal quarter. The Company believes, however, based on currently available information, that the results of any pending matters, in the aggregate, will not have a material effect on its business or financial condition.

Stockholders' Equity

12 Months Ended

Dec. 31, 2017

Equity [Abstract]

Stockholders' Equity

13.	STOCKHOLDERS’ EQUITY

Share Repurchase Program—During the year ended December 31, 2017 and since 2014, the Board of Directors of Lazard authorized the repurchase of Class A common stock as set forth in the table below.

Date	Repurchase Authorization		Expiration
April 2014	$	200,000	December 31, 2015
February 2015	$	150,000	December 31, 2016
January 2016	$	200,000	December 31, 2017
April 2016	$	113,182	December 31, 2017
November 2016	$	236,000	December 31, 2018
October 2017	$	200,000	December 31, 2019

The Company expects that the share repurchase program will primarily be used to offset a portion of the shares that have been or will be issued under the Lazard Ltd 2008 Incentive Compensation Plan (the “2008 Plan”). Pursuant to the share repurchase program, purchases have been made in the open market or through privately negotiated transactions. The rate at which the Company purchases shares in connection with the share repurchase program may vary from period to period due to a variety of factors. Purchases with respect to such program are set forth in the table below:

Years Ended December 31:	Number of Shares Purchased		Average Price Per Share
2015		3,438,789	$	50.24
2016		8,551,271	$	35.11
2017		6,956,097	$	44.10

There were 10,747,142 and 7,628,786 shares of Class A common stock held by our subsidiaries at December 31, 2017 and 2016, respectively. Such shares of Class A common stock are reported, at cost, as “Class A common stock held by subsidiaries” on the accompanying consolidated statements of financial condition.

During 2017, 2016 and 2015, certain of our executive officers received Class A common stock in connection with the vesting or settlement of previously-granted deferred equity incentive awards. The vesting or settlement of such equity awards gave rise to a tax payable by the executive officers, and, consistent with our past practice, the Company purchased shares of Class A common stock from the executive officers equal in value to all or a portion of the estimated amount of such tax. In addition, during the years ended December 31, 2017 and 2016, the Company purchased shares of Class A common stock from an executive officer. The aggregate value of all such purchases in 2017, 2016 and 2015 was approximately $14,700, $4,900 and $17,700, respectively.

As of December 31, 2017, a total of $248,384 of share repurchase authorization remained available under the Company’s share repurchase program, $48,384 of which will expire on December 31, 2018 and $200,000 of which will expire on December 31, 2019.

During the year ended December 31, 2017, the Company had in place trading plans under Rule 10b5-1 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), pursuant to which it effected stock repurchases in the open market.

Preferred Stock—Lazard Ltd has 15,000,000 authorized shares of preferred stock, par value $0.01 per share, inclusive of its Series A and Series B preferred stock. Series A and Series B preferred shares were issued in connection with certain prior year business acquisitions and were each non-participating securities convertible into Class A common stock, and had no voting or dividend rights. As of December 31, 2017 and 2016, no shares of Series A or Series B preferred stock were outstanding, respectively. As of December 31, 2015, 7,921 shares of Series A preferred stock were outstanding, and no shares of Series B preferred stock were outstanding. At December 31, 2015, no shares of Series A preferred stock were convertible into shares of Class A common stock on a contingent or a non-contingent basis.

Accumulated Other Comprehensive Income (Loss), Net of Tax—The tables below reflect the balances of each component of AOCI at December 31, 2017, 2016 and 2015 and activity during the years then ended:

	Currency Translation Adjustments			Employee Benefit Plans			Total AOCI			Amount Attributable to Noncontrolling Interests			Total Lazard Ltd AOCI
Balance, January 1, 2017	$	(155,204	)	$	(159,020	)	$	(314,224	)	$	(2	)	$	(314,222	)
Activity January 1 to December 31, 2017:
Other comprehensive income before reclassifications		71,669			2,085			73,754			1			73,753
Adjustments for items reclassified to earnings, net of tax					7,951			7,951						7,951
Net other comprehensive income		71,669			10,036			81,705			1			81,704
Balance, December 31, 2017	$	(83,535	)	$	(148,984	)	$	(232,519	)	$	(1	)	$	(232,518	)

	Currency Translation Adjustments			Employee Benefit Plans			Total AOCI			Amount Attributable to Noncontrolling Interests			Total Lazard Ltd AOCI
Balance, January 1, 2016	$	(97,284	)	$	(137,073	)	$	(234,357	)	$	(1	)	$	(234,356	)
Activity January 1 to December 31, 2016:
Other comprehensive loss before reclassifications		(57,920	)		(24,473	)		(82,393	)		(1	)		(82,392	)
Adjustments for items reclassified to earnings, net of tax		-			2,526			2,526			-			2,526
Net other comprehensive loss		(57,920	)		(21,947	)		(79,867	)		(1	)		(79,866	)
Balance, December 31, 2016	$	(155,204	)	$	(159,020	)	$	(314,224	)	$	(2	)	$	(314,222	)

	Currency Translation Adjustments			Employee Benefit Plans			Total AOCI			Amount Attributable to Noncontrolling Interests			Total Lazard Ltd AOCI
Balance, January 1, 2015	$	(46,102	)	$	(154,665	)	$	(200,767	)	$	(1	)	$	(200,766	)
Activity January 1 to December 31, 2015:
Other comprehensive income (loss) before reclassifications		(51,182	)		11,283			(39,899	)		-			(39,899	)
Adjustments for items reclassified to earnings, net of tax		-			6,309			6,309			-			6,309
Net other comprehensive income (loss)		(51,182	)		17,592			(33,590	)		-			(33,590	)
Balance, December 31, 2015	$	(97,284	)	$	(137,073	)	$	(234,357	)	$	(1	)	$	(234,356	)

The table below reflects adjustments for items reclassified out of AOCI, by component, for the years ended December 31, 2017, 2016 and 2015:

	Year Ended December 31,
	2017		2016		2015
Amortization relating to employee benefit plans (a)	$	10,171	$	4,283	$	7,816
Less - related income taxes		2,220		1,757		1,507
Total reclassifications, net of tax	$	7,951	$	2,526	$	6,309

(a)	Included in the computation of net periodic benefit cost (see Note 15). Such amounts are included in “compensation and benefits” expense on the consolidated statements of operations.

Noncontrolling Interests—Noncontrolling interests principally represent interests held in Edgewater’s management vehicles that the Company is deemed to control, but does not own.

The tables below summarize net income attributable to noncontrolling interests for the years ended December 31, 2017, 2016 and 2015 and noncontrolling interests as of December 31, 2017 and 2016, in the Company’s consolidated financial statements:

	Net Income Attributable to Noncontrolling Interests Year Ended December 31,
	2017		2016		2015
Edgewater	$	6,259	$	5,992	$	6,557
Other		5		2		2
Total	$	6,264	$	5,994	$	6,559

	Noncontrolling Interests as of December 31,
	2017		2016
Edgewater	$	58,568	$	57,238
Other		534		588
Total	$	59,102	$	57,826

Dividends Declared, January 31, 2018—On January 31, 2018, the Board of Directors of Lazard declared dividends totaling $1.71 per share, comprised of a quarterly dividend of $0.41 per share, and an extra cash dividend of $1.30 per share, on our Class A common stock. The dividends are payable on February 23, 2018, to stockholders of record on February 12, 2018.

Incentive Plans

12 Months Ended

Dec. 31, 2017

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Incentive Plans

14.	INCENTIVE PLANS

Share-Based Incentive Plan Awards

A description of Lazard Ltd’s 2008 Plan and 2005 Equity Incentive Plan (the “2005 Plan”) and activity with respect thereto during the years ended December 31, 2017, 2016 and 2015 is presented below.

Shares Available Under the 2008 Plan and 2005 Plan

The 2008 Plan authorizes the issuance of shares of Class A common stock pursuant to the grant or exercise of stock options, stock appreciation rights, restricted stock units (“RSUs”), performance-based restricted stock units (“PRSUs”) and other share-based awards. Under the 2008 Plan, the maximum number of shares available is based on a formula that limits the aggregate number of shares that may, at any time, be subject to awards that are considered “outstanding” under the 2008 Plan to 30% of the then-outstanding shares of Class A common stock. The 2008 Plan will expire in May 2018, although unvested awards granted under the 2008 Plan before it expires will remain outstanding and continue to be subject to its terms.

The 2005 Plan authorized the issuance of up to 25,000,000 shares of Class A common stock pursuant to the grant or exercise of stock options, stock appreciation rights, RSUs and other share-based awards. Each RSU or similar award granted under the 2005 Plan represents a contingent right to receive one share of Class A common stock, at no cost to the recipient. The fair value of such awards is generally determined based on the closing market price of Class A common stock at the date of grant. The 2005 Plan expired in the second quarter of 2015, although unvested awards granted under the 2005 Plan remain outstanding and continue to be subject to its terms.

The following reflects the amortization expense recorded with respect to share-based incentive plans within “compensation and benefits” expense (with respect to RSUs, PRSUs and restricted stock awards) and “professional services” expense (with respect to deferred stock units (“DSUs”)) within the Company’s accompanying consolidated statements of operations:

	Year Ended December 31,
	2017		2016		2015
Share-based incentive awards:
RSUs	$	190,821	$	171,188	$	166,395
PRSUs		40,767		43,018		36,529
Restricted Stock		39,369		45,536		22,342
DSUs		2,008		1,720		1,457
Total	$	272,965	$	261,462	$	226,723

The ultimate amount of compensation and benefits expense relating to share-based awards is dependent upon the actual number of shares of Class A common stock that vest. The Company periodically assesses the forfeiture rates used for such estimates, including as a result of any applicable performance conditions. A change in estimated forfeiture rates or performance results in a cumulative adjustment to compensation and benefits expense and also would cause the aggregate amount of compensation expense recognized in future periods to differ from the estimated unrecognized compensation expense described below.

For purposes of calculating diluted net income per share, RSUs, DSUs and restricted stock awards are included in the diluted weighted average shares of Class A common stock outstanding using the “treasury stock” method. PRSUs are included in the diluted weighted average shares of Class A common stock outstanding to the extent the performance conditions are met at the end of the reporting period, also using the “treasury stock” method.

The Company’s share-based incentive plans and awards are described below.

RSUs and DSUs

RSUs generally require future service as a condition for the delivery of the underlying shares of Class A common stock (unless the recipient is then eligible for retirement under the Company’s retirement policy) and convert into shares of Class A common stock on a one-for-one basis after the stipulated vesting periods. PRSUs, which are RSUs that are also subject to service-based vesting conditions, have additional performance conditions, and are described below. The grant date fair value of the RSUs, net of an estimated forfeiture rate, is amortized over the vesting periods or requisite service periods (generally one-third after two years, and the remaining two-thirds after the third year), and is adjusted for actual forfeitures over such period.

RSUs generally include a dividend participation right that provides that during vesting periods each RSU is attributed additional RSUs (or fractions thereof) equivalent to any dividends paid on Class A common stock during such period. During the years ended December 31, 2017, 2016 and 2015, issuances of RSUs pertaining to such dividend participation rights and respective charges to “retained earnings”, net of estimated forfeitures (with corresponding credits to “additional paid-in-capital”), consisted of the following:

	Year Ended December 31,
	2017		2016		2015
Number of RSUs issued		985,584		1,085,354		693,714
Charges to retained earnings, net of estimated forfeitures	$	41,746	$	37,284	$	34,255

Non-executive members of the Board of Directors (“Non-Executive Directors”) receive approximately 55% of their annual compensation for service on the Board of Directors and its committees in the form of DSUs, which resulted in 31,280, 38,771 and 23,961 DSUs granted during the years ended December 31, 2017, 2016 and 2015, respectively. Their remaining compensation is payable in cash, which they may elect to receive in the form of additional DSUs under the Directors’ Fee Deferral Unit Plan described below. DSUs are convertible into shares of Class A common stock at the time of cessation of service to the Board of Directors and, for purposes of calculating diluted net income per share, are included in the diluted weighted average shares of Class A common stock outstanding using the “treasury stock” method. DSUs include a cash dividend participation right equivalent to dividends paid on Class A common stock.

The Company’s Directors’ Fee Deferral Unit Plan permits the Non-Executive Directors to elect to receive additional DSUs in lieu of some or all of their cash fees. The number of DSUs granted to a Non-Executive Director pursuant to this election will equal the value of cash fees that the applicable Non-Executive Director has elected to forego pursuant to such election, divided by the market value of a share of Class A common stock on the date immediately preceding the date of the grant. During the years ended December 31, 2017, 2016 and 2015, 13,882, 10,043 and 2,482 DSUs, respectively, had been granted pursuant to such Plan.

DSU awards are expensed at their fair value on their date of grant, inclusive of amounts related to the Directors’ Fee Deferral Unit Plan.

The following is a summary of activity relating to RSUs and DSUs during the three-year period ended December 31, 2017:

	RSUs					DSUs
	Units			Weighted Average Grant Date Fair Value		Units			Weighted Average Grant Date Fair Value
Balance, January 1, 2015		13,529,116		$	35.19		286,227		$	34.21
Granted (including 693,714 RSUs relating to dividend participation)		4,296,386		$	48.57		26,443		$	55.11
Forfeited		(469,776	)	$	43.54		-			-
Vested		(7,756,068	)	$	31.12		-			-
Balance, December 31, 2015		9,599,658		$	44.06		312,670		$	35.98
Granted (including 1,085,354 RSUs relating to dividend participation)		6,878,306		$	34.86		48,814		$	35.23
Forfeited		(239,432	)	$	39.53		-			-
Vested		(4,540,394	)	$	39.16		(84,759	)	$	35.30
Balance, December 31, 2016		11,698,138		$	40.65		276,725		$	36.05
Granted (including 985,584 RSUs relating to dividend participation)		5,437,591		$	43.03		45,162		$	44.46
Forfeited		(217,720	)	$	40.20		-			-
Vested		(3,998,163	)	$	45.26		(43,465	)	$	35.77
Balance, December 31, 2017		12,919,846		$	40.23		278,422		$	37.46

In connection with RSUs that vested during the years ended December 31, 2017, 2016 and 2015, the Company satisfied its minimum statutory tax withholding requirements in lieu of delivering 1,290,601, 1,421,396 and 2,249,935 shares of Class A common stock during such respective years. Accordingly, 2,707,562, 3,118,998 and 5,506,133 shares of Class A common stock held by the Company were delivered during the years ended December 31, 2017, 2016 and 2015, respectively.

As of December 31, 2017, estimated unrecognized RSU compensation expense was approximately $139,793, with such expense expected to be recognized over a weighted average period of approximately 0.8 years subsequent to December 31, 2017.

Restricted Stock

The following is a summary of activity related to shares of restricted Class A common stock associated with compensation arrangements during the three-year period ended December 31, 2017:

	Restricted Shares			Weighted Average Grant Date Fair Value
Balance, January 1, 2015		729,827		$	38.63
Granted		576,886		$	50.88
Forfeited		(45,851	)	$	50.17
Vested		(547,124	)	$	39.50
Balance, December 31, 2015		713,738		$	47.12
Granted		1,795,258		$	36.76
Forfeited		(34,051	)	$	40.48
Vested		(819,872	)	$	37.16
Balance, December 31, 2016		1,655,073		$	40.95
Granted		841,355		$	42.58
Forfeited		(66,592	)	$	40.80
Vested		(491,676	)	$	45.35
Balance, December 31, 2017		1,938,160		$	40.54

In connection with shares of restricted Class A common stock that vested during the years ended December 31, 2017, 2016 and 2015, the Company satisfied its minimum statutory tax withholding requirements in lieu of delivering 150,470, 141,026 and 108,833 shares of Class A common stock during such respective years. Accordingly, 341,206, 678,846 and 438,291 shares of Class A common stock held by the Company were delivered during the years ended December 31, 2017, 2016 and 2015, respectively.

The restricted stock awards include a cash dividend participation right equivalent to dividends paid on Class A common stock during the period, which will vest concurrently with the underlying restricted stock award. At December 31, 2017, estimated unrecognized restricted stock expense was approximately $27,181, with such expense to be recognized over a weighted average period of approximately 0.8 years subsequent to December 31, 2017.

PRSUs

PRSUs are RSUs that are subject to both performance-based and service-based vesting conditions. The number of shares of Class A common stock that a recipient will receive upon vesting of a PRSU will be calculated by reference to certain performance metrics that relate to the Company’s performance over a three-year period. The target number of shares of Class A common stock subject to each PRSU is one; however, based on the achievement of the performance criteria, the number of shares of Class A common stock that may be received in connection with each PRSU generally can range from zero to two times the target number. PRSUs will vest on a single date approximately three years following the date of the grant, provided the applicable service and performance conditions are satisfied. In addition, the performance metrics applicable to each PRSU will be evaluated on an annual basis at the end of each fiscal year during the performance period and, if the Company has achieved a threshold level of performance with respect to the fiscal year, 25% of the target number of shares of Class A common stock subject to each PRSU will no longer be at risk of forfeiture based on the achievement of performance criteria. PRSUs include dividend participation rights that provide that during vesting periods the target number of PRSUs (or, following the relevant performance period, the actual number of shares of Class A common stock that are no longer subject to performance conditions) receive dividend equivalents at the same rate that dividends are paid on Class A common stock during such periods. These dividend equivalents are credited as RSUs that are not subject to the performance-based vesting criteria but are otherwise subject to the same restrictions as the underlying PRSUs to which they relate.

The following is a summary of activity relating to PRSUs during the three-year period ended December 31, 2017:

	PRSUs			Weighted Average Grant Date Fair Value
Balance, January 1, 2015		1,347,148		$	37.79
Granted (a)		368,389		$	52.85
Vested		(696,499	)	$	35.96
Balance, December 31, 2015		1,019,038		$	44.49
Granted (a)		627,956		$	32.91
Performance units earned (b)		360,783		$	41.20
Vested		(417,021	)	$	38.43
Balance, December 31, 2016		1,590,756		$	40.76
Granted (a)		458,113		$	43.76
Performance units earned (b)		368,389		$	47.74
Vested		(825,565	)	$	42.27
Balance, December 31, 2017		1,591,693		$	42.46

(a)	Represents PRSU awards granted during the relevant year at the target payout level.

(b)	Represents shares of Class A common stock earned during the fiscal year under the performance criteria of previously-granted PRSU awards in excess of the target payout level of such awards.

In connection with certain PRSUs that vested or were settled during the years ended December 31, 2017, 2016 and 2015, the Company satisfied its minimum statutory tax withholding requirements in lieu of delivering 127,530, 64,169 and 32,086 shares of Class A common stock during such respective years. Accordingly, 698,035, 352,852 and 664,413 shares of Class A common stock held by the Company were delivered during the years ended December 31, 2017, 2016 and 2015, respectively.

Compensation expense recognized for PRSU awards is determined by multiplying the number of shares of Class A common stock underlying such awards that, based on the Company’s estimate, are considered probable of vesting, by the grant date fair value. As of December 31, 2017, the total estimated unrecognized compensation expense was approximately $9,174, and the Company expects to amortize such expense over a weighted-average period of approximately 0.7 years subsequent to December 31, 2017.

LFI and Other Similar Deferred Compensation Arrangements

Commencing in February 2011, the Company granted LFI to eligible employees. In connection with LFI and other similar deferred compensation arrangements, which generally require future service as a condition for vesting, the Company recorded a prepaid compensation asset and a corresponding compensation liability on the grant date based upon the fair value of the award. The prepaid asset is amortized on a straight-line basis over the applicable vesting periods or requisite service periods (which are generally similar to the comparable periods for RSUs), and is charged to “compensation and benefits” expense within the Company’s consolidated statement of operations. LFI and similar deferred compensation arrangements that do not require future service are expensed immediately. The related compensation liability is accounted for at fair value as a derivative liability, which contemplates the impact of estimated forfeitures, and is adjusted for changes in fair value primarily related to changes in value of the underlying investments.

The following is a summary of activity relating to LFI and other similar deferred compensation arrangements during the years ended December 31, 2017 and 2016:

	Prepaid Compensation Asset			Compensation Liability
Balance, January 1, 2017	$	49,650		$	170,388
Granted		77,580			77,580
Settled		-			(96,025	)
Forfeited		(992	)		(1,819	)
Amortization		(67,575	)		-
Change in fair value related to:
Increase in fair value of underlying investments		-			23,526
Adjustment for estimated forfeitures		-			6,634
Other		1,692			2,017
Balance, December 31, 2017	$	60,355		$	182,301

	Prepaid Compensation Asset			Compensation Liability
Balance, January 1, 2016	$	75,703		$	193,574
Granted		52,121			52,121
Settled		-			(77,457	)
Forfeited		(2,942	)		(5,380	)
Amortization		(73,340	)		-
Change in fair value related to:
Increase in fair value of underlying investments		-			3,318
Adjustment for estimated forfeitures		-			4,671
Other		(1,892	)		(459	)
Balance, December 31, 2016	$	49,650		$	170,388

The amortization of the prepaid compensation asset will generally be recognized over a weighted average period of approximately 0.9 years subsequent to December 31, 2017.

The following is a summary of the impact of LFI and other similar deferred compensation arrangements on “compensation and benefits” expense within the accompanying consolidated statements of operations for the years ended December 31, 2017, 2016 and 2015:

	Year Ended Ended December 31,
	2017		2016		2015
Amortization, net of forfeitures	$	73,382	$	75,573	$	85,563
Change in the fair value of underlying investments		23,526		3,318		(3,827	)
Total	$	96,908	$	78,891	$	81,736

Incentive Awards Granted In February 2018

In February 2018, the Company granted approximately $351,000 of deferred incentive compensation awards (including PRSUs valued at the target payout level) to eligible employees. These grants included: RSUs or shares of restricted Class A common stock; deferred incentive compensation awards that allow eligible employees the choice of receiving a portion of their award in a combination of (i) LFI and (ii) additional RSUs or shares of restricted Class A common stock; deferred cash awards; and a portion of fund managers’ year-end incentive compensation that is reinvested in certain asset management funds.

The RSUs, restricted Class A common stock and LFI granted each provide for one-third vesting on or around March 2, 2020 and the remaining two-thirds vesting on or around March 1, 2021. The PRSUs granted provide for vesting on or around March 1, 2021, provided that the applicable service and performance conditions are satisfied, and will convert into Class A common stock within a range equal to zero to two times the target number of shares of Class A common stock subject to the awards. Compensation expense with respect to such incentive awards will generally be recognized over the vesting period, with such compensation expense to be recognized over a weighted average period of approximately 2.7 years.

Employee Benefit Plans

12 Months Ended

Dec. 31, 2017

Compensation And Retirement Disclosure [Abstract]

Employee Benefit Plans

15.	EMPLOYEE BENEFIT PLANS

The Company provides retirement and other post-retirement benefits to certain of its employees through defined benefit pension plans (the “pension plans”) and, until December 2016, in the U.S., a partially funded contributory medical post-retirement plan covering certain qualifying U.S. employees (the “medical plan” and together with the pension plans, the “post-retirement plans”). The Company also offers defined contribution plans to its employees. The post-retirement plans generally provide benefits to participants based on average levels of compensation. Expenses related to the Company’s employee benefit plans are included in “compensation and benefits” expense on the consolidated statements of operations.

Medical Plan—The medical plan was previously amended such that effective January 1, 2005 the plan limited post-retirement medical coverage to then former and current employees of the Company that were hired prior to January 1, 2005 and attained the age of 55 on or prior to December 31, 2005, and their dependents. Effective December 31, 2016, the Company ceased offering the medical plan.

In October 2016, the Company paid participants in the medical plan $2,936 in the aggregate to settle in full the Company’s obligations under the medical plan. The settlement of such obligations resulted in the recognition of a gain of $1,788 that is recorded as a reduction to compensation and benefits expense in the consolidated statements of operations for the year ended December 31, 2016.

Employer Contributions to Pension Plans—The Company’s funding policy for its U.S. and non-U.S. pension plans is to fund when required or when applicable upon an agreement with the plans’ trustees (the “Trustees”). Management also evaluates from time to time whether to make voluntary contributions to the plans.

The Company does not expect to make a contribution to the U.S. pension plan during the year ending December 31, 2018. The Company expects to contribute approximately $21,000 to the other non-U.S. pension plans during the year ending December 31, 2018.

The following table summarizes the changes in the benefit obligations, the fair value of the assets, the funded status and amounts recognized in the consolidated statements of financial condition for the post-retirement plans. The Company uses December 31 as the measurement date for its post-retirement plans.

	Pension Plans						Medical Plan
	2017			2016			2017		2016
Change in benefit obligation
Benefit obligation at beginning of year	$	718,821		$	694,187		$	-	$	4,750
Service cost		1,413			1,235					11
Interest cost		16,240			19,871					167
Actuarial (gain) loss		2,702			135,164					(1,639	)
Benefits paid		(44,589	)		(31,904	)				(3,289	)
Foreign currency translation and other adjustments		69,244			(99,732	)
Benefit obligation at end of year		763,831			718,821			-		-
Change in plan assets
Fair value of plan assets at beginning of year		646,119			656,084
Actual return on plan assets		43,624			119,287
Employer contributions		16,844			11,343					3,289
Benefits paid		(42,022	)		(29,384	)				(3,289	)
Foreign currency translation and other adjustments		63,716			(111,211	)
Fair value of plan assets at end of year		728,281			646,119			-		-
Funded (deficit) at end of year	$	(35,550	)	$	(72,702	)	$	-	$	-
Amounts recognized in the consolidated statements of financial condition at December 31, 2017 and 2016 consist of:
Prepaid pension asset (included in “other assets”)	$	16,189		$	822		$	-	$	-
Accrued benefit liability (included in “other liabilities”)		(51,739	)		(73,524	)
Net amount recognized	$	(35,550	)	$	(72,702	)	$	-	$	-
Amounts recognized in AOCI (excluding tax benefits of $35,154 and $33,864 at December 31, 2017 and 2016, respectively) consist of:
Actuarial net loss (gain)	$	184,135		$	192,855		$	-	$	-
Prior service cost		-			30
Net amount recognized	$	184,135		$	192,885		$	-	$	-

The following table summarizes the fair value of plan assets, the accumulated benefit obligation and the projected benefit obligation at December 31, 2017 and 2016:

	U.S. Pension Plans				Non-U.S. Pension Plans				Total
	As Of December 31,				As Of December 31,				As Of December 31,
	2017		2016		2017		2016		2017		2016
Fair value of plan assets	$	24,644	$	22,161	$	703,637	$	623,958	$	728,281	$	646,119
Accumulated benefit obligation	$	35,376	$	33,868	$	728,455	$	684,953	$	763,831	$	718,821
Projected benefit obligation	$	35,376	$	33,868	$	728,455	$	684,953	$	763,831	$	718,821

The following table summarizes the components of net periodic benefit cost (credit), the return on the Company’s post-retirement plan assets, benefits paid, contributions and other amounts recognized in AOCI for the years ended December 31, 2017, 2016 and 2015:

	Pension Plans									Medical Plan
	For The Year Ended									For The Year Ended
	December 31,									December 31,
	2017			2016			2015			2017		2016			2015
Components of Net Periodic Benefit Cost (Credit):
Service cost	$	1,413		$	1,235		$	1,530		$	-	$	11		$	27
Interest cost		16,240			19,871			24,600			-		167			179
Expected return on plan assets		(25,300	)		(27,337	)		(28,301	)		-		-			-
Amortization of:
Prior service cost		30			2,369			2,376			-		-			-
Net actuarial loss (gain)		10,141			3,888			5,440			-		(185	)		-
Settlement loss (gain)		807			-			-			-		(1,788	)		-
Net periodic benefit cost (credit)	$	3,331		$	26		$	5,645		$	-	$	(1,795	)	$	206


Actual return on plan assets	$	43,624		$	119,287		$	9,873
Employer contributions	$	16,844		$	11,343		$	39,301		$	-	$	3,289		$	276
Benefits paid	$	42,022		$	29,384		$	32,321		$	-	$	3,289		$	276
Other changes in plan assets and benefit obligations recognized in AOCI (excluding tax expense (benefit) of $(1,287), $(3,448) and $7,151 during the years ended December 31, 2017, 2016 and 2015, respectively):
Net actuarial (gain) loss	$	(17,357	)	$	51,626		$	(4,650	)	$	-	$	(1,638	)	$	(695	)
Reclassification of prior service (cost) credit to earnings		(30	)		(2,369	)		(2,376	)		-		-			-
Reclassification of actuarial gain (loss) to earnings		(10,141	)		(3,888	)		(5,440	)		-		1,973			-
Currency translation and other adjustments		18,778			(20,309	)		(11,582	)		-		-			-
Total recognized in AOCI	$	(8,750	)	$	25,060		$	(24,048	)	$	-	$	335		$	(695	)
Net amount recognized in total periodic benefit cost and AOCI	$	(5,419	)	$	25,086		$	(18,403	)	$	-	$	(1,460	)	$	(489	)

The amounts in AOCI on the consolidated statement of financial condition as of December 31, 2017 that are expected to be recognized as components of net periodic benefit cost (credit) for the year ending December 31, 2018 are as follows:

Pension

Plans

Net actuarial loss

5,072

The assumptions used to develop actuarial present value of the projected benefit obligation and net periodic pension cost as of or for the years ended December 31, 2017, 2016 and 2015 are set forth below:

	Pension Plans									Medical Plan
	December 31,									December 31,
	2017			2016			2015			2017		2016			2015
Weighted average assumptions used to determine benefit obligations:
Discount rate		2.3	%		2.5	%		3.5	%		-		-			3.9	%
Weighted average assumptions used to determine net periodic benefit cost:
Discount rate		2.2	%		1.9	%		2.6	%		-		3.9	%		3.7	%
Expected long-term rate of return on plan assets		3.8	%		4.6	%		4.3	%		-		-			-
Healthcare cost trend rates used to determine net periodic benefit cost:
Initial											-		6.5	%		7.0	%
Ultimate											-		5.0	%		5.0	%
Year ultimate trend rate achieved											-	2019			2019

Generally, the Company determined the discount rates for its defined benefit plans by utilizing indices for long-term, high-quality bonds and ensuring that the discount rate does not exceed the yield reported for those indices after adjustment for the duration of the plans’ liabilities.

In selecting the expected long-term rate of return on plan assets, the Company considered the average rate of earnings expected on the funds invested or to be invested to provide for the benefits of the plan, giving consideration to expected returns on different asset classes held by the plans in light of prevailing economic conditions as well as historical returns. This basis is consistent for all years presented.

Expected Benefit Payments—The following table summarizes the expected benefit payments for the Company’s pension plans for each of the next five fiscal years and in the aggregate for the five fiscal years thereafter:

	Pension
	Plans
2018	$	24,631
2019		25,347
2020		25,351
2021		26,981
2022		29,287
2023-2027		153,490

Plan Assets—The following tables present the categorization of our pension plans’ assets as of December 31, 2017 and 2016, measured at fair value, into a fair value hierarchy and investments measured at NAV or its equivalent as a practical expedient in accordance with fair value measurement disclosure requirements:

	As of December 31, 2017
	Level 1		Level 2		Level 3		NAV (a)		Total
Assets:
Cash	$	11,544	$	-	$	-	$	-	$	11,544
Debt		73,728		-		-		-		73,728
Equities		36,854		-		-		-		36,854
Funds:
Alternative investments		-		-		-		25,938		25,938
Debt		11,002		-		-		363,915		374,917
Equity		192,875		3,746		-		8,015		204,636
Derivative		-		664		-		-		664
Total	$	326,003	$	4,410	$	-	$	397,868	$	728,281

	As of December 31, 2016
	Level 1		Level 2		Level 3		NAV (a)		Total
Assets:
Cash	$	23,341	$	-	$	-	$	-	$	23,341
Debt		63,431		-		-		-		63,431
Equities		29,287		-		-		-		29,287
Funds:
Alternative investments		1,216		-		-		23,062		24,278
Debt		10,494		-		-		320,560		331,054
Equity		167,981		-		-		6,129		174,110
Derivative		-		618		-		-		618
Total	$	295,750	$	618	$	-	$	349,751	$	646,119

(a)	Represents certain investments measured at NAV or its equivalent as a practical expedient in determining fair value. In accordance with current accounting guidance, these investments have not been classified in the fair value hierarchy.

Included in equity funds are $102,455 and $97,933 as of December 31, 2017 and 2016, respectively, that are invested in funds managed by LAM.

Consistent with the plans’ investment strategies, at December 31, 2017 and 2016, the Company’s U.S. pension plan had 55% and 53%, respectively, of the plans’ assets invested in equity funds in Level 1 and measured at NAV or its equivalent as a practical expedient and 45% and 47%, respectively, invested in Level 1 debt funds. The Company’s non-U.S. pension plans at December 31, 2017 and 2016 had 32% and 31%, respectively, of the plans’ assets invested in equities and equity funds that are primarily Level 1 assets; 62% and 62%, respectively, of the plans’ assets invested in debt and debt funds that are Level 1 assets and measured at NAV or its equivalent as a practical expedient, and 6% and 7%, respectively, of the plans’ assets invested in cash, which is a Level 1 asset, or in alternative investment funds that are primarily measured at NAV.

Investment Policies and Strategies—The primary investment goal is to ensure that the pension plans remain well funded, taking account of the likely future risks to investment returns and contributions. As a result, a portfolio of assets is maintained with appropriate liquidity and diversification that can be expected to generate long-term future returns that minimize the long-term costs of the pension plans without exposing the plans to an unacceptable risk of under-funding. The Company’s likely future ability to pay such contributions as are required to maintain the funded status of the plans over a reasonable time period is considered when determining the level of risk that is appropriate. The fair value of plan investments classified as Level 1 assets are based on market quotes. The fair value of plan investments measured at NAV or its equivalent as a practical expedient is determined based on information provided by external fund administrators and such investments are redeemable in the near term.

Defined Contribution Plans—Pursuant to certain matching contributions, the Company contributes to employer sponsored defined contribution plans. Such contributions amounted to $15,065, $14,454 and $12,493 for the years ended December 31, 2017, 2016 and 2015, respectively, which are included in “compensation and benefits” expense on the consolidated statements of operations.

Income Taxes

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Income Taxes

16.	INCOME TAXES

Lazard Ltd, through its subsidiaries, is subject to U.S. federal income taxes on all of its U.S. operating income, as well as on the portion of non-U.S. income attributable to its U.S. subsidiaries. In addition, Lazard Ltd, through its subsidiaries, is subject to state and local taxes on its income apportioned to various state and local jurisdictions. Outside the U.S., Lazard Group operates principally through subsidiary corporations that are subject to local income taxes in foreign jurisdictions. Lazard Group is also subject to UBT attributable to its operations apportioned to New York City.

On December 22, 2017, the Tax Cuts and Jobs Act (“the Tax Act”) was enacted. The Tax Act significantly revises the U.S. corporate income tax system by, among other changes, lowering the corporate income tax rate from 35% to 21%, implementing a partial territorial tax system and imposing a one-time repatriation tax on the deemed repatriated earnings of foreign subsidiaries. The Tax Act also includes several provisions that may limit the benefit of the tax rate reduction, such as restricting the deductibility of interest expense and other corporate business expenses. The Tax Act further includes anti-base erosion provisions such as the base erosion and anti-abuse tax and tax on global intangible low-taxed income.

As a result of the reduction of the U.S. federal corporate tax rate to 21%, the Company was required to remeasure its deferred tax assets and liabilities at the new federal income tax rate of 21% based on the balances that existed on the date of the enactment of the Tax Act. The lower corporate tax rate resulted in a reduction of our net deferred tax assets by approximately $420,000. See also Note 18 for the impact of the Tax Act to the tax receivable agreement obligation.

The Tax Act also requires companies to pay a one-time repatriation tax on previously unremitted earnings of certain non-U.S. corporate subsidiaries. Most of the Company’s operations outside the U.S. are conducted in “pass-through” entities for U.S. income tax purposes, and, as a result, the deemed repatriation transition tax does not apply to these pass-through entities or their earnings. The Company instead provides for U.S. income taxes on a current basis for those earnings. The Company also conducts operations outside the U.S. through foreign corporate subsidiaries, and the Company recorded approximately $1,000 of deferred tax expense related to the one-time repatriation tax on the foreign earnings of those corporate subsidiaries.

In accordance with the guidance provided by Staff Accounting Bulletin No. 118, the Company has recognized the provisional tax impact related to the one-time deemed repatriation tax on certain foreign earnings and the remeasurement of our deferred tax assets. The impact of the Tax Act on the Company may differ from these provisional estimates, due to, among other items, the issuance of additional regulatory guidance, our interpretations of the provisions of the Tax Act, changes to certain estimates and amounts related to the earnings and profits of certain subsidiaries and the filing of our tax returns. We will recognize any changes to the provisional amounts as we refine our estimates and expect to complete our analysis of the provisional items during the second half of 2018.

On January 1, 2017, the Company adopted new accounting guidance on share-based incentive compensation. As a result of the adoption of this new guidance, the Company recognized excess tax benefits of approximately $9,000 from the vesting of share-based incentive compensation in the provision for income taxes in the consolidated statements of operations for the year ended December 31, 2017. The Company also recorded deferred tax assets of $81,544, net of a valuation allowance of $12,090, as of January 1, 2017, for previously unrecognized excess tax benefits (including tax benefits from dividends or dividend equivalents) on share-based incentive compensation, with an offsetting adjustment to retained earnings. See Note 3 for further information on the adoption of this new guidance.

The components of the Company’s provision (benefit) for income taxes for the years ended December 31, 2017, 2016 and 2015, and a reconciliation of the U.S. federal statutory income tax rate to the Company’s effective tax rates for such years, are shown below.

	Year Ended December 31,
	2017			2016		2015
Current:
Federal	$	349		$	1,766	$	8,177
Foreign		64,119			54,253		78,086
State and local (primarily UBT)		(32	)		4,090		4,970
Total current		64,436			60,109		91,233
Deferred:
Federal		480,085			50,602		(988,900	)
Foreign		12,928			1,354		(3,960	)
State and local		8,150			11,704		(107,925	)
Total deferred		501,163			63,660		(1,100,785	)
Total	$	565,599		$	123,769	$	(1,009,552	)

	Year Ended December 31,
	2017			2016			2015
U.S. federal statutory income tax rate		35.0	%		35.0	%		35.0	%
U.S. tax reform		43.4			-			-
Foreign source income not subject to U.S. income tax		(4.2	)		(9.3	)		419.4
Change in U.S. federal valuation allowance		(3.4	)		(3.6	)		5477.0
Share-based incentive compensation		(4.0	)		-			-
Foreign taxes		(0.2	)		(0.1	)		(361.6	)
State and local taxes		2.4			3.0			522.2
Income of non-controlling interests		(0.3	)		(0.3	)		13.8
Other, net		(0.2	)		(0.8	)		(31.5	)
Effective income tax rate (a)		68.5	%		23.9	%		6074.3	%

(a)

For the year ended December 31, 2015, the effective tax rate on “operating income (loss)” includes (i) the significant effect of the release of substantially all of our valuation allowance on deferred tax assets and the recognition of deferred tax assets associated with the recording of the tax receivable agreement obligation, as described below, and (ii) the negative impact on “operating income (loss)” as a result of the provision pursuant to the tax receivable agreement.

See Note 20 regarding “operating income (loss)” by geographic region.

Deferred income taxes are provided for the effects of temporary differences between the tax basis of an asset or liability and its reported amount in the consolidated statements of financial condition. These temporary differences result in taxable or deductible amounts in future years. Details of the Company’s deferred tax assets and liabilities are as follows:

	December 31,
	2017			2016
Deferred Tax Assets:
Basis adjustments (a)	$	339,133		$	692,430
Compensation and benefits		175,456			197,750
Net operating loss and tax credit carryforwards		239,959			285,694
Depreciation and amortization		1,537			850
Other		34,615			53,895
Gross deferred tax assets		790,700			1,230,619
Valuation allowance		(61,456	)		(69,593	)
Deferred tax assets (net of valuation allowance)		729,244			1,161,026
Deferred Tax Liabilities:
Depreciation and amortization		17,257			26,539
Compensation and benefits		23,251			5,447
Goodwill		21,749			27,932
Other		26,134			34,499
Deferred tax liabilities		88,391			94,417
Net deferred tax assets	$	640,853		$	1,066,609

(a)	The basis adjustments recorded as of December 31, 2017 and 2016 are primarily the result of additional basis from acquisitions of interests, including the impact of the tax receivable agreement obligation.

Prior to 2015, the Company had a valuation allowance on substantially all of our deferred tax assets at that time. However, in assessing our valuation allowance as of June 30, 2015, we considered all available information, including the magnitude of recent and current operating results, the relatively long duration of statutory carryforward periods, our historical experience utilizing tax attributes prior to their expiration dates, the historical volatility of operating results of these entities and our assessment regarding the sustainability of their profitability. At that time, we concluded that there was a sufficient history of sustained profitability at these entities that it was more likely than not that these entities would be able to realize deferred tax assets. Accordingly, during the period ended June 30, 2015, we released substantially all of the valuation allowance against the deferred tax assets held by these entities.

As a result, during the year ended December 31, 2015, we recorded a deferred tax benefit of approximately $878,000. In addition, included in basis adjustments, we also recorded (i) a separate deferred tax benefit of approximately $378,000 that reflected the tax deductibility of payments under the tax receivable agreement and (ii) a deferred tax expense of approximately $161,000 relating to the reduction of a deferred tax asset as a result of the partial extinguishment of our tax receivable agreement obligation. See Note 18 for more information regarding our accrual under the tax receivable agreement in the second quarter of 2015 and the partial extinguishment of our tax receivable agreement obligation in the third quarter of 2015.

Certain of our tax-paying entities have individually experienced losses on a cumulative three year basis or have tax attributes that may expire unused. In addition, one of our tax paying entities has recorded a valuation allowance on substantially all of its deferred tax assets due to the combined effect of operating losses in certain subsidiaries of that entity as well as foreign taxes that together substantially offset any U.S. tax liability. Taking into account all available information, we cannot determine that it is more likely than not that deferred tax assets held by these entities will be realized. Consequently, we have recorded valuation allowances on $61,456 and $69,593 of deferred tax assets held by these entities as of December 31, 2017 and 2016, respectively.

Changes in the deferred tax assets valuation allowance for the years ended December 31, 2017, 2016 and 2015 was as follows:

	Year Ended December 31,
	2017			2016			2015
Beginning Balance	$	69,593		$	89,251		$	1,044,152
Credited to provision (benefit) for income taxes		(23,670	)		(15,981	)		(954,487	)
Charged (credited) to other comprehensive income and other (a)		15,533			(3,677	)		(414	)
Ending Balance	$	61,456		$	69,593		$	89,251

(a)

In accordance with the new accounting guidance described above, 2017 includes recognition of previously unrecognized excess tax benefits offset by a valuation allowance of $12,090 recorded to retained earnings. 2016 includes acquisition-related deferred tax assets offset by a valuation allowance in the amount of $2,271.

The Company had net operating loss and tax credit carryforwards for which related deferred tax assets of $239,959 were recorded at December 31, 2017 primarily relating to:

(i)

indefinite-lived carryforwards (subject to various limitations) of approximately $26,000 in Australia, Germany, Hong Kong, Saudi Arabia, Singapore and Spain; and

(ii)

certain carryforwards of approximately $188,000 in the U.S., which begin expiring in 2029.

With few exceptions, the Company is no longer subject to income tax examination by foreign tax authorities and by U.S. federal, state and local tax authorities for years prior to 2012. While we are under examination in various tax jurisdictions with respect to certain open years, the Company does not expect that the result of any final determination related to these examinations will have a material impact on its financial statements. Developments with respect to such examinations are monitored on an ongoing basis and adjustments to tax liabilities are made as appropriate.

A reconciliation of the beginning to the ending amount of gross unrecognized tax benefits (excluding interest and penalties) for the years ended December 31, 2017, 2016 and 2015 is as follows:

	Year Ended December 31,
	2017			2016			2015
Balance, January 1 (excluding interest and penalties of $15,392, $13,083 and $13,004, respectively)	$	78,396		$	77,280		$	68,224
Increases in gross unrecognized tax benefits relating to tax positions taken during:
Prior years		1,598			5,891			-
Current year		19,823			18,438			22,212
Decreases in gross unrecognized tax benefits relating to:
Tax positions taken during prior years		(2,961	)		(5,316	)		(621	)
Settlements with tax authorities		-			(1,706	)		-
Lapse of the applicable statute of limitations		(18,182	)		(16,191	)		(12,535	)
Balance, December 31 (excluding interest and penalties of $15,136, $15,392 and $13,083, respectively)	$	78,674		$	78,396		$	77,280

Additional information with respect to unrecognized tax benefits is as follows:

	Year Ended December 31,
	2017			2016		2015
Unrecognized tax benefits at the end of the year that, if recognized, would favorably affect the effective tax rate (includes interest and penalties of $15,136, $15,392 and $13,083, respectively)	$	78,841		$	81,564	$	74,785
Unrecognized tax benefits that, if recognized, would not affect the effective tax rate	$	14,969		$	12,224	$	15,578
Interest and penalties recognized in current income tax expense (after giving effect to the reversal of interest and penalties of $6,185, $3,143 and $3,865, respectively)	$	(256	)	$	2,309	$	79

The Company anticipates that it is reasonably possible that approximately $20,000 of unrecognized tax benefits, including interest and penalties recorded at December 31, 2017, may be recognized within 12 months as a result of the lapse of the statute of limitations in various tax jurisdictions.

Net Income Per Share of Class A Common Stock

12 Months Ended

Dec. 31, 2017

Earnings Per Share [Abstract]

Net Income Per Share of Class A Common Stock

17.	NET INCOME PER SHARE OF CLASS A COMMON STOCK

The Company’s basic and diluted net income per share calculations for the years ended December 31, 2017, 2016 and 2015 are computed as described below.

Basic Net Income Per Share

Numerator—utilizes net income attributable to Lazard Ltd for the respective years.

Denominator—utilizes the weighted average number of shares of Class A common stock outstanding for the respective years, plus applicable adjustments to such shares associated with shares of Class A common stock issuable on a non-contingent basis.

Diluted Net Income Per Share

Numerator—utilizes net income attributable to Lazard Ltd for the respective years as in the basic net income per share calculation described above.

Denominator —utilizes the weighted average number of shares of Class A common stock outstanding for the respective years as in the basic net income per share calculation described above, plus, to the extent dilutive, the incremental number of shares of Class A common stock required to settle share-based incentive compensation.

The calculations of the Company’s basic and diluted net income per share and weighted average shares outstanding for the years ended December 31, 2017, 2016 and 2015 are presented below:

	Year Ended December 31,
	2017		2016		2015
Net income attributable to Lazard Ltd - basic	$	253,583	$	387,698	$	986,373
Net income attributable to Lazard Ltd - diluted	$	253,583	$	387,698	$	986,373
Weighted average number of shares of Class A common stock outstanding		121,309,174		124,635,160		125,294,261
Add - adjustment for shares of Class A common stock issuable on a non-contingent basis		264,268		135,241		72,011
Weighted average number of shares of Class A common stock outstanding - basic		121,573,442		124,770,401		125,366,272
Add - dilutive effect, as applicable, of:
Weighted average number of incremental shares of Class A common stock issuable from share-based incentive compensation		10,906,286		7,863,229		7,878,274
Weighted average number of shares of Class A common stock outstanding - diluted		132,479,728		132,633,630		133,244,546
Net income attributable to Lazard Ltd per share of Class A common stock:
Basic	$	2.09	$	3.11	$	7.87
Diluted	$	1.91	$	2.92	$	7.40

Related Parties

12 Months Ended

Dec. 31, 2017

Related Parties

18.	RELATED PARTIES

Sponsored Funds

The Company serves as an investment advisor for certain affiliated investment companies and fund entities and receives management fees and, for the alternative investment funds, performance-based incentive fees for providing such services. Investment advisory fees relating to such services were $649,089, $516,667 and $534,752 for the years ended December 31, 2017, 2016 and 2015, respectively, and are included in “asset management fees” on the consolidated statements of operations. Of such amounts, $69,107 and $49,944 remained as receivables at December 31, 2017 and 2016, respectively, and are included in “fees receivable” on the consolidated statements of financial condition.

Tax Receivable Agreement

The Second Amended and Restated Tax Receivable Agreement, dated as of October 26, 2015 (the “Amended and Restated Tax Receivable Agreement”), between Lazard and LTBP Trust, a Delaware statutory trust (the “Trust”), provides for the payment by our subsidiaries to the Trust of (i) approximately 45% (following the July 2015 purchase described below) of the amount of cash savings, if any, in U.S. federal, state and local income tax or franchise tax that we actually realize as a result of certain increases in tax basis and of certain other tax benefits related to the Amended and Restated Tax Receivable Agreement, and (ii) an amount that we currently expect will approximate 85% of the cash tax savings that may arise from tax benefits attributable to payments under the Amended and Restated Tax Receivable Agreement. Our subsidiaries expect to benefit from the balance of cash savings, if any, in income tax that our subsidiaries realize. Any amount paid by our subsidiaries to the Trust will generally be distributed to the owners of the Trust, including our executive officers, in proportion to their beneficial interests in the Trust.

For purposes of the Amended and Restated Tax Receivable Agreement, cash savings in income and franchise tax will be computed by comparing our subsidiaries’ actual income and franchise tax liability to the amount of such taxes that our subsidiaries would have been required to pay had there been no increase in the tax basis of certain tangible and intangible assets of Lazard Group attributable to our subsidiaries’ interest in Lazard Group and had our subsidiaries not entered into the Amended and Restated Tax Receivable Agreement. The term of the Amended and Restated Tax Receivable Agreement will continue until approximately 2033 or, if earlier, until all relevant tax benefits have been utilized or expired.

As described in Note 16, during the period ended June 30, 2015, we released substantially all of our valuation allowance against deferred tax assets. As a result, we accrued a corresponding liability of $961,948 during the quarter ended June 30, 2015 for amounts relating to the Amended and Restated Tax Receivable Agreement at that time.

The amount of the Amended and Restated Tax Receivable Agreement liability is an undiscounted amount based upon currently enacted tax laws, including the Tax Act, the current structure of the Company and various assumptions regarding potential future operating profitability. The assumptions reflected in the estimate involve significant judgment. For example, if our structure were to change or our annual taxable income were to increase, we could be required to accelerate payments under the Amended and Restated Tax Receivable Agreement. As such, the actual amount and timing of payments under the Amended and Restated Tax Receivable Agreement could differ materially from our estimates. Any changes in the amount of the estimated liability would be recorded as a non-compensation expense in the consolidated statement of operations. Adjustments, if necessary, to the related deferred tax assets would be recorded through the “provision (benefit) for income taxes”.

In July 2015, we purchased approximately 47% of the then-outstanding beneficial interests in the Trust from certain owners of the Trust for $42,222 in cash, which resulted in the automatic cancellation of such beneficial interests and the extinguishment of a significant portion of our payment obligations under the Amended and Restated Tax Receivable Agreement. The extinguishment of these payment obligations resulted in a pre-tax gain of $420,792 recorded in “provision pursuant to tax receivable agreement” on the consolidated statement of operations for the year ended December 31, 2015. In addition, the extinguishment of these payment obligations resulted in a reduction of the tax benefits that would have been attributable to the actual payments and, accordingly, we recorded a deferred tax expense of approximately $161,000 on the consolidated statement of operations for the year ended December 31, 2015.

For the years ended December 31, 2017 and 2015, the Company recorded a “provision (benefit) pursuant to tax receivable agreement” on the consolidated statements of operations of $(202,546) and $547,691, respectively. As described in Note 16, the Tax Act reduced the U.S. corporate tax rate from 35% to 21% which required the Company to remeasure the tax receivable agreement obligation. Pursuant to the change in the U.S. corporate tax rate, in 2017, the Company reduced the tax receivable agreement obligation by $202,546. The cumulative liability relating to our obligations under the Amended and Restated Tax Receivable Agreement as of December 31, 2017 and 2016 was $310,275 and $513,610, respectively, and is recorded in “tax receivable agreement obligation” on the consolidated statements of financial condition. The balance at December 31, 2017 reflects a payment made under the Amended and Restated Tax Receivable Agreement in the year ended December 31, 2017 of $789.

Other

See Note 13 for information regarding related party transactions pertaining to shares repurchased from certain of our executive officers.

Regulatory Authorities

12 Months Ended

Dec. 31, 2017

Regulatory Capital Requirements [Abstract]

Regulatory Authorities

19.	REGULATORY AUTHORITIES

LFNY is a U.S. registered broker-dealer and is subject to the net capital requirements of Rule 15c3-1 under the Exchange Act. Under the basic method permitted by this rule, the minimum required net capital, as defined, is a specified fixed percentage (6 ²/₃%) of total aggregate indebtedness recorded in LFNY’s Financial and Operational Combined Uniform Single (“FOCUS”) report filed with the Financial Industry Regulatory Authority (“FINRA”), or $100, whichever is greater. In addition, the ratio of aggregate indebtedness (as defined) to net capital may not exceed 15:1. At December 31, 2017, LFNY’s regulatory net capital was $156,289, which exceeded the minimum requirement by $151,311. LFNY’s aggregate indebtedness to net capital ratio was 0.48:1 as of December 31, 2017.

Certain U.K. subsidiaries of the Company, including LCL, Lazard Fund Managers Limited and Lazard Asset Management Limited (collectively, the “U.K. Subsidiaries”) are regulated by the Financial Conduct Authority. At December 31, 2017, the aggregate regulatory net capital of the U.K. Subsidiaries was $192,717, which exceeded the minimum requirement by $173,756.

CFLF, under which asset management and commercial banking activities are carried out in France, is subject to regulation by the Autorité de Contrôle Prudentiel et de Résolution (“ACPR”) for its banking activities conducted through its subsidiary, LFB. LFB, as a registered bank, is engaged primarily in commercial and private banking services for clients and funds managed by LFG (asset management), and other clients, and asset-liability management. The investment services activities of the Paris group, exercised through LFB and other subsidiaries of CFLF, primarily LFG, also are subject to regulation and supervision by the Autorité des Marchés Financiers. At December 31, 2017, the consolidated regulatory net capital of CFLF was $140,353, which exceeded the minimum requirement set for regulatory capital levels by $85,904. In addition, pursuant to the consolidated supervision rules in the European Union, LFB, in particular, as a French credit institution, is required to be supervised by a regulatory body, either in the U.S. or in the European Union. During the third quarter of 2013, the Company and the ACPR agreed on terms for the consolidated supervision of LFB and certain other non-Financial Advisory European subsidiaries of the Company (referred to herein, on a combined basis, as the “combined European regulated group”) under such rules. Under this supervision, the combined European regulated group is required to comply with minimum requirements for regulatory net capital to be reported on a quarterly basis and satisfy periodic financial and other reporting obligations. At December 31, 2017, the regulatory net capital of the combined European regulated group was $170,933, which exceeded the minimum requirement set for regulatory capital levels by $68,025. Additionally, the combined European regulated group, together with our European Financial Advisory entities, is required to perform an annual risk assessment and provide certain other information on a periodic basis, including financial reports and information relating to financial performance, balance sheet data and capital structure.

Certain other U.S. and non-U.S. subsidiaries are subject to various capital adequacy requirements promulgated by various regulatory and exchange authorities in the countries in which they operate. At December 31, 2017, for those subsidiaries with regulatory capital requirements, their aggregate net capital was $162,440, which exceeded the minimum required capital by $134,275.

At December 31, 2017, each of these subsidiaries individually was in compliance with its regulatory capital requirements.

Any new or expanded rules and regulations that may be adopted in countries in which we operate (including regulations that have not yet been proposed) could affect us in other ways.

Segment Information

12 Months Ended

Dec. 31, 2017

Segment Reporting [Abstract]

Segment Information

20.	SEGMENT INFORMATION

The Company’s reportable segments offer different products and services and are managed separately as different levels and types of expertise are required to effectively manage the segments’ transactions. Each segment is reviewed to determine the allocation of resources and to assess its performance. The Company’s principal operating activities are included in its Financial Advisory and Asset Management business segments as described in Note 1. In addition, as described in Note 1, the Company records selected other activities in its Corporate segment.

The Company’s segment information for the years ended December 31, 2017, 2016 and 2015 is prepared using the following methodology:

•

Revenue and expenses directly associated with each segment are included in determining operating income.

•

Expenses not directly associated with specific segments are allocated based on the most relevant measures applicable, including headcount, square footage and other factors.

•

Segment assets are based on those directly associated with each segment, and include an allocation of certain assets relating to various segments, based on the most relevant measures applicable, including headcount, square footage and other factors.

The Company allocates investment gains and losses, interest income and interest expense among the various segments based on the segment in which the underlying asset or liability is reported.

Each segment’s operating expenses include (i) compensation and benefits expenses incurred directly in support of the businesses and (ii) other operating expenses, which include directly incurred expenses for occupancy and equipment, marketing and business development, technology and information services, professional services, fund administration and outsourced services and indirect support costs (including compensation and other operating expenses related thereto) for administrative services. Such administrative services include, but are not limited to, accounting, tax, human resources, legal, facilities management and senior management activities.

For the years ended December 31, 2017, 2016 and 2015, no individual client constituted more than 10% of the net revenue of any of the Company’s business segments.

Management evaluates segment results based on net revenue and operating income (loss) and believes that the following information provides a reasonable representation of each segment’s contribution with respect to net revenue, operating income (loss) and total assets:

		As Of Or For The Year Ended December 31,
		2017			2016			2015
Financial Advisory	Net Revenue	$	1,387,682		$	1,301,044		$	1,279,628
	Operating Expenses (a)		1,143,586			1,017,055			1,005,837
	Operating Income	$	244,096		$	283,989		$	273,791
	Total Assets	$	843,142		$	907,035		$	763,374
Asset Management	Net Revenue	$	1,255,820		$	1,051,316		$	1,111,105
	Operating Expenses (a)		810,870			769,737			736,798
	Operating Income	$	444,950		$	281,579		$	374,307
	Total Assets	$	756,398		$	645,653		$	640,034
Corporate	Net Revenue	$	809		$	(18,989	)	$	(37,125	)
	Operating Expenses (a)/(b)		(135,591	)		29,118			627,593
	Operating Income (Loss)	$	136,400		$	(48,107	)	$	(664,718	)
	Total Assets	$	3,329,137		$	3,003,820		$	3,074,366
Total	Net Revenue	$	2,644,311		$	2,333,371		$	2,353,608
	Operating Expenses (a)		1,818,865			1,815,910			2,370,228
	Operating Income (Loss)	$	825,446		$	517,461		$	(16,620	)
	Total Assets	$	4,928,677		$	4,556,508		$	4,477,774

(a)	Operating expenses include depreciation and amortization of property as set forth in table below.

	Year Ended December 31,
	2017		2016		2015
Financial Advisory	$	6,596	$	5,661	$	4,412
Asset Management		2,830		3,666		2,957
Corporate		22,072		23,937		25,416
Total	$	31,498	$	33,264	$	32,785

(b)

Operating expenses include a benefit of $202,546 for the year ended December 31, 2017, and a provision of $547,691 for the year ended December 31, 2015, recorded for the provision (benefit) pursuant to the tax receivable agreement. See Note 18 for information regarding the tax receivable agreement obligation.

Geographic Information

Due to the highly integrated nature of international financial markets, the Company manages its business based on the profitability of the enterprise as a whole. Accordingly, management believes that profitability by geographic region is not necessarily meaningful. The Company’s revenue and identifiable assets are generally allocated based on the country or domicile of the legal entity providing the service.

Effective January 1, 2017, the Company’s reporting by geographic region was transitioned from the Company’s previously disclosed North America, Europe and rest of the world regions to the Americas; Europe, Middle East and Africa (“EMEA”); and Asia Pacific. Comparable prior year information has been recast to reflect our revised geographic presentation.

The following table sets forth the net revenue from, and identifiable assets for, the Company and its consolidated subsidiaries by geographic region allocated on the basis described above.

	As Of Or For The Year Ended December 31,
	2017		2016		2015
Net Revenue:
Americas	$	1,558,070	$	1,399,285	$	1,322,898
EMEA		903,525		795,932		813,136
Asia Pacific		182,716		138,154		217,574
Total	$	2,644,311	$	2,333,371	$	2,353,608
Operating Income (Loss):
Americas (a)	$	596,044	$	335,887	$	(259,538	)
EMEA		193,781		168,745		163,612
Asia Pacific		35,621		12,829		79,306
Total	$	825,446	$	517,461	$	(16,620	)
Identifiable Assets:
Americas	$	2,600,412	$	3,015,267	$	2,811,850
EMEA		2,039,385		1,286,149		1,405,555
Asia Pacific		288,880		255,092		260,369
Total	$	4,928,677	$	4,556,508	$	4,477,774

(a)

Operating income (loss) includes a benefit of $202,546 for the year ended December 31, 2017, and a provision of $547,691 for the year ended December 31, 2015, recorded for the provision (benefit) pursuant to the tax receivable agreement. See Note 18 for information regarding the tax receivable agreement obligation.

Supplemental Financial Information - Quarterly Results

12 Months Ended

Dec. 31, 2017

Quarterly Financial Information Disclosure [Abstract]

Supplemental Financial Information - Quarterly Results

SUPPLEMENTAL FINANCIAL INFORMATION

QUARTERLY RESULTS (UNAUDITED)

The following represents the Company’s unaudited quarterly results for the years ended December 31, 2017 and 2016. These quarterly results were prepared in conformity with generally accepted accounting principles and reflect all adjustments that are, in the opinion of management, necessary for a fair statement of the results. These adjustments are of a normal recurring nature.

	2017 Fiscal Quarter
	First		Second		Third		Fourth			Year
	(dollars in thousands, except per share data)
Net revenue	$	623,464	$	717,180	$	624,859	$	678,808		$	2,644,311
Operating expenses		473,267		544,679		480,647		320,272			1,818,865
Operating income	$	150,197	$	172,501	$	144,212	$	358,536		$	825,446
Net income (loss)	$	110,430	$	120,901	$	111,470	$	(82,954	)	$	259,847
Less - net income attributable to noncontrolling interests		2,877		523		2,260		604			6,264
Net income (loss) attributable to Lazard Ltd	$	107,553	$	120,378	$	109,210	$	(83,558	)	$	253,583
Attributable to Lazard Ltd Class A common stockholders:
Net income per share of common stock:
Basic	$	0.88	$	0.98	$	0.90	$	(0.70	)	$	2.09
Diluted	$	0.81	$	0.91	$	0.82	$	(0.70	)	$	1.91
Dividends declared per share of common stock	$	1.58	$	0.41	$	0.41	$	0.41		$	2.81

	2016 Fiscal Quarter
	First		Second		Third		Fourth		Year
	(dollars in thousands, except per share data)
Net revenue	$	498,218	$	534,680	$	608,908	$	691,565	$	2,333,371
Operating expenses		399,841		421,444		459,916		534,709		1,815,910
Operating income	$	98,377	$	113,236	$	148,992	$	156,856	$	517,461
Net income	$	70,723	$	81,364	$	112,618	$	128,987	$	393,692
Less - net income attributable to noncontrolling interests		3,900		1,007		82		1,005		5,994
Net income attributable to Lazard Ltd	$	66,823	$	80,357	$	112,536	$	127,982	$	387,698
Attributable to Lazard Ltd Class A common stockholders:
Net income per share of common stock:
Basic	$	0.53	$	0.64	$	0.90	$	1.04	$	3.11
Diluted	$	0.50	$	0.61	$	0.85	$	0.96	$	2.92
Dividends declared per share of common stock	$	1.55	$	0.38	$	0.38	$	0.38	$	2.69

Schedule I - Condensed Financial Information of Registrant (Parent Company Only)

12 Months Ended

Dec. 31, 2017

Condensed Financial Information Of Parent Company Only Disclosure Abstract

Schedule I - Condensed Financial Information of Registrant (Parent Company Only)

LAZARD LTD

(parent company only)

CONDENSED STATEMENTS OF FINANCIAL CONDITION

DECEMBER 31, 2017 AND 2016

(dollars in thousands, except per share data)

	December 31,
	2017			2016
ASSETS
Cash and cash equivalents	$	3,921		$	3,916
Investments in subsidiaries, equity method		(1,061,259	)		(534,642	)
Due from subsidiaries		2,259,112			1,766,875
Other assets		-			13
Total assets	$	1,201,774		$	1,236,162
LIABILITIES AND STOCKHOLDERS’ EQUITY
Liabilities:
Due to subsidiaries	$	1,847		$	65
Other liabilities		124			110
Total liabilities		1,971			175
Commitments and contingencies
STOCKHOLDERS’ EQUITY
Preferred stock, par value $.01 per share; 15,000,000 shares authorized:
Series A—no shares issued and outstanding					-
Series B—no shares issued and outstanding					-
Common stock:
Class A, par value $.01 per share (500,000,000 shares authorized; 129,766,091 shares issued at December 31, 2017 and 2016, including shares held by subsidiaries as indicated below)		1,298			1,298
Additional paid-in-capital		788,140			688,231
Retained earnings		1,080,413			1,134,186
Accumulated other comprehensive loss, net of tax		(232,518	)		(314,222	)
		1,637,333			1,509,493
Class A common stock held by subsidiaries, at cost (10,747,142 and 7,628,786 shares at December 31, 2017 and 2016, respectively)		(437,530	)		(273,506	)
Total stockholders’ equity		1,199,803			1,235,987
Total liabilities and stockholders’ equity	$	1,201,774		$	1,236,162

LAZARD LTD

(parent company only)

CONDENSED STATEMENTS OF OPERATIONS

FOR THE YEARS ENDED DECEMBER 31, 2017, 2016 AND 2015

(dollars in thousands)

	Year Ended December 31,
	2017		2016		2015
REVENUE
Equity in earnings of subsidiaries	$	145,008	$	326,366	$	931,036
Interest and other income		110,381		63,019		57,258
Total revenue		255,389		389,385		988,294
OPERATING EXPENSES
Professional services		1,692		1,580		1,779
Other		114		107		142
Total operating expenses		1,806		1,687		1,921
NET INCOME	$	253,583	$	387,698	$	986,373

LAZARD LTD

(parent company only)

CONDENSED STATEMENTS OF COMPREHENSIVE INCOME

FOR THE YEARS ENDED DECEMBER 31, 2017, 2016 AND 2015

(dollars in thousands)

	Year Ended December 31,
	2017		2016			2015
NET INCOME	$	253,583	$	387,698		$	986,373
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX:
Currency translation adjustments		71,668		(57,919	)		(51,182	)
Employee benefit plans:
Actuarial gain (loss) (net of tax expense (benefit) of $(3,507), $(5,205) and $5,644 for the years ended December 31, 2017, 2016 and 2015, respectively)		2,085		(24,473	)		11,283
Adjustments for items reclassified to earnings (net of tax expense of $2,220, $1,757 and $1,507 for the years ended December 31, 2017, 2016 and 2015, respectively)		7,951		2,526			6,309
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX		81,704		(79,866	)		(33,590	)
COMPREHENSIVE INCOME	$	335,287	$	307,832		$	952,783

LAZARD LTD

(parent company only)

CONDENSED STATEMENTS OF CASH FLOWS

FOR THE YEARS ENDED DECEMBER 31, 2017, 2016 AND 2015

(dollars in thousands)

	Year Ended December 31,
	2017			2016			2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$	253,583		$	387,698		$	986,373
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in earnings of subsidiaries		(145,008	)		(326,366	)		(931,036	)
Dividends received from subsidiaries		63,822			-			-
Changes in due to/from subsidiaries		169,056			273,051			233,519
Changes in other operating assets and liabilities		27			(233	)		250
Net cash provided by operating activities		341,480			334,150			289,106
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital contribution to subsidiaries		(25	)		-			-
Net cash used in investing activities		(25	)		-			-
CASH FLOWS FROM FINANCING ACTIVITIES:
Class A common stock dividends		(341,450	)		(336,138	)		(290,684	)
Net cash used in financing activities		(341,450	)		(336,138	)		(290,684	)
Net increase (decrease) in cash and cash equivalents		5			(1,988	)		(1,578	)
Cash and cash equivalents, January 1		3,916			5,904			7,482
Cash and cash equivalents, December 31	$	3,921		$	3,916		$	5,904

LAZARD LTD

(parent company only)

NOTES TO CONDENSED FINANCIAL STATEMENTS

1.	BASIS OF PRESENTATION

The accompanying Lazard Ltd condensed financial statements (the “Parent Company Financial Statements”), including the notes thereto, should be read in conjunction with the consolidated financial statements of Lazard Ltd and its subsidiaries (the “Company”) and the notes thereto.

The Parent Company Financial Statements as of December 31, 2017 and 2016, and for each of the three years in the period ended December 31, 2017, are prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”), which require management to make estimates and assumptions that affect the reported amounts of assets and liabilities, revenue and expenses, and the disclosures in the condensed financial statements. Management believes that the estimates utilized in the preparation of the condensed financial statements are reasonable. Actual results could differ materially from these estimates.

The Parent Company Financial Statements include investments in subsidiaries, accounted for under the equity method.

For the period ended December 31, 2016, equity in earnings of subsidiaries also includes a gain of $12,668 related to the portion of a business acquired in the fourth quarter of 2016 that was previously owned by one of the Company’s subsidiaries.

F-1

- Definition

The entire disclosure for condensed financial information, including the financial position, cash flows, and the results of operations of the registrant (parent company) as of the same dates or for the same periods for which audited consolidated financial statements are being presented. Alternatively, the details of this disclosure can be reported by the specific parent company taxonomy elements, indicating the appropriate date and period contexts in an instance document.

+ References + Details

Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2017

Accounting Policies [Abstract]

Foreign Currency Translation

Use of Estimates

•

the adequacy of the allowance for doubtful accounts;

•

the realization of deferred tax assets and adequacy of tax reserves for uncertain tax positions;

•

the measurement of our tax receivable agreement obligation;

•

the outcome of litigation;

•

the carrying amount of goodwill and other intangible assets;

•

the amortization period of intangible assets;

•

the valuation of shares issued or issuable that contain transfer restrictions;

•

the vesting of share-based and other deferred compensation plan awards; and

•

other matters that affect the reported amounts and disclosure of contingencies in the consolidated financial statements.

Cash and Cash Equivalents

Cash and Cash Equivalents—The Company defines cash equivalents as short-term, highly liquid securities and cash deposits with original maturities of 90 days or less when purchased.

Deposits with Banks and Short-Term Investments

Cash Deposited with Clearing Organizations and Other Segregated Cash

Allowance for Doubtful Accounts

See Note 4 for additional information regarding receivables.

Investments

See Notes 5 and 6 for additional information regarding the Company’s investments.

Property-net

Goodwill and Other Intangible Assets

The Company completed its annual goodwill review as of November 1, 2017, and determined that no impairment existed.

See Note 9 with respect to goodwill and other intangible assets.

Derivative Instruments

Deposits and Other Customer Payables

Deposits and Other Customer Payables—Principally relates to LFB customer-related demand deposits, both interest-bearing and non-interest bearing.

Securities Sold, Not Yet Purchased

Contingent Consideration Liabilities

Fair Value of Financial Assets and Liabilities

Revenue Recognition

Receivables relating to asset management and incentive fees are reported in “fees receivable” on the consolidated statements of financial condition.

On January 1, 2018, the Company adopted new revenue recognition guidance. See Note 3.

Soft Dollar Arrangements

Equity-Based Incentive Compensation Awards

Cost Saving Initiatives and Staff Reductions

Income Taxes

•

future reversals of existing taxable temporary differences;

•

future taxable income exclusive of reversing temporary differences and carryforwards;

•

taxable income in prior carryback years; and

•

tax-planning strategies.

The assessment regarding whether a valuation allowance is required or should be adjusted also considers all available information, including the following:

•

nature, frequency, magnitude and duration of any past losses and current operating results;

•

duration of statutory carryforward periods;

•

historical experience with tax attributes expiring unused; and

•

near-term and medium-term financial outlook.

The Company recognizes interest and/or penalties related to unrecognized tax benefits in “provision (benefit) for income taxes”. See Note 16 for additional information relating to income taxes.

Recent Accounting Developments

Employer Contributions to Pension Plans

Computation of Basic and Diluted Net Income per Share

Basic Net Income Per Share

Numerator—utilizes net income attributable to Lazard Ltd for the respective years.

Diluted Net Income Per Share

Numerator—utilizes net income attributable to Lazard Ltd for the respective years as in the basic net income per share calculation described above.

Organization

•

Basis of Presentation

•

Voting interest entities (“VOEs”) where the Company holds a majority of the voting interest in such VOEs, and

•

Fair Value Measurement Policy

Level 1.

Assets and liabilities whose values are based on unadjusted quoted prices for identical assets or liabilities in an active market that Lazard has the ability to access.

Level 2.

Level 3.

The fair value of securities sold, not yet purchased, is classified as Level 1 when the fair values are based on unadjusted quoted prices in active markets.

Receivables (Tables)

12 Months Ended

Dec. 31, 2017

Receivables [Abstract]

Schedule of Activity in Allowance for Doubtful Accounts

Activity in the allowance for doubtful accounts for the years ended December 31, 2017, 2016 and 2015 was as follows:

	Year Ended December 31,
	2017			2016			2015
Beginning Balance	$	16,386		$	12,882		$	23,540
Bad debt expense, net of recoveries		15,419			10,055			3,125
Charge-offs, foreign currency translation and other adjustments		(8,059	)		(6,551	)		(13,783	)
Ending Balance	$	23,746		$	16,386		$	12,882

Investments (Tables)

12 Months Ended

Dec. 31, 2017

Investments Schedule [Abstract]

Company's Investments and Securities Sold, Not Yet Purchased

The Company’s investments and securities sold, not yet purchased, consist of the following at December 31, 2017 and 2016:

	December 31,
	2017		2016
Interest-bearing deposits	$	556	$	456
Debt		6		-
Equities		45,257		41,017
Funds:
Alternative investments (a)		20,993		32,441
Debt (a)		84,077		74,597
Equity (a)		199,618		188,268
Private equity		76,679		122,421
		381,367		417,727
Equity method		-		222
Total investments		427,186		459,422
Less:
Interest-bearing deposits		556		456
Equity method		-		222
Investments, at fair value	$	426,630	$	458,744
Securities sold, not yet purchased, at fair value (included in “other liabilities”)	$	7,338	$	4,482

(a)

Schedule of Trading Securities Net Unrealized Investment Gains and Losses

	Year Ended December 31,
	2017		2016		2015
Net unrealized investment gains (losses)	$	27,192	$	11,816	$	(19,681	)

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2017

Fair Value Disclosures [Abstract]

Schedule of Classification of Investments and Certain Other Assets and Liabilities Measured at Fair Value on Recurring Basis and Investments Measured at NAV

	December 31, 2017
	Level 1		Level 2		Level 3		NAV		Total
Assets:
Investments:
Debt	$	6	$	-	$	-	$	-	$	6
Equities		43,665		-		1,592		-		45,257
Funds:
Alternative investments		17,353		-		-		3,640		20,993
Debt		84,071		-		-		6		84,077
Equity		199,565		-		-		53		199,618
Private equity		-		-		-		76,679		76,679
Derivatives		-		3,732		-		-		3,732
Total	$	344,660	$	3,732	$	1,592	$	80,378	$	430,362
Liabilities:
Securities sold, not yet purchased	$	7,338	$	-	$	-	$	-	$	7,338
Contingent consideration liability		-		-		28,941		-		28,941
Derivatives		-		198,417		-		-		198,417
Total	$	7,338	$	198,417	$	28,941	$	-	$	234,696

	December 31, 2016
	Level 1		Level 2		Level 3		NAV		Total
Assets:
Investments:
Equities	$	39,509	$	-	$	1,508	$	-	$	41,017
Funds:
Alternative investments		25,316		-		-		7,125		32,441
Debt		74,591		-		-		6		74,597
Equity		188,229		-		-		39		188,268
Private equity		-		-		-		122,421		122,421
Derivatives		-		1,993		-		-		1,993
Total	$	327,645	$	1,993	$	1,508	$	129,591	$	460,737
Liabilities:
Securities sold, not yet purchased	$	4,482	$	-	$	-	$	-	$	4,482
Contingent consideration liability		-		-		22,608		-		22,608
Derivatives		-		182,223		-		-		182,223
Total	$	4,482	$	182,223	$	22,608	$	-	$	209,313

Summary of Changes in Fair Value of Company's Level 3 Assets and Liabilities

The following tables provide a summary of changes in fair value of the Company’s Level 3 assets and liabilities for the years ended December 31, 2017, 2016 and 2015:

	Year Ended December 31, 2017
	Beginning Balance		Net Unrealized/ Realized Gains/Losses Included In Earnings (a)		Purchases/ Acquisitions		Sales/ Dispositions/ Settlements			Foreign Currency Translation Adjustments		Ending Balance
Assets:
Investments:
Equities	$	1,508	$	14	$	1,661	$	(1,669	)	$	78	$	1,592
Total Level 3 Assets	$	1,508	$	14	$	1,661	$	(1,669	)	$	78	$	1,592

Liabilities:
Contingent consideration liability	$	22,608	$	6,582	$	-	$	(249	)	$	-	$	28,941
Total Level 3 Liabilities	$	22,608	$	6,582	$	-	$	(249	)	$	-	$	28,941

	Year Ended December 31, 2016
	Beginning Balance		Net Unrealized/ Realized Gains/Losses Included In Earnings (a)		Purchases/ Acquisitions		Sales/ Dispositions/ Settlements			Foreign Currency Translation Adjustments			Ending Balance
Assets:
Investments:
Equities	$	1,276	$	248	$	-	$	-		$	(16	)	$	1,508
Total Level 3 Assets	$	1,276	$	248	$	-	$	-		$	(16	)	$	1,508

Liabilities:
Contingent consideration liability	$	-	$	32,725	$	19,950	$	(30,067	)	$	-		$	22,608
Total Level 3 Liabilities	$	-	$	32,725	$	19,950	$	(30,067	)	$	-		$	22,608

	Year Ended December 31, 2015
	Beginning Balance		Net Unrealized/ Realized Gains/Losses Included In Earnings (a)		Purchases/ Acquisitions		Sales/ Dispositions/ Settlements		Foreign Currency Translation Adjustments			Ending Balance
Assets:
Investments:
Equities	$	1,315	$	14	$	-	$	-	$	(53	)	$	1,276
Total Level 3 Assets	$	1,315	$	14	$	-	$	-	$	(53	)	$	1,276

(a)

Financial Instruments Not Measured at Fair Value

	December 31, 2017
			Fair Value Measurements Using:
	Carrying Value		Fair Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Financial Assets:
Cash and cash equivalents	$	1,483,836	$	1,483,836	$	1,483,836	$	-	$	-
Deposits with banks and short-term investments		935,431		935,431		935,431		-		-
Cash deposited with clearing organizations and other segregated cash		35,539		35,539		35,539		-		-
Interest-bearing financing receivables		80,536		82,492		-		-		82,492
Interest-bearing deposits (included within investments)		556		556		556		-		-
Financial Liabilities:
Deposits and other customer payables	$	992,338	$	992,338	$	992,338	$	-	$	-
Senior debt		1,190,383		1,230,254		-		1,230,254		-

	December 31, 2016
			Fair Value Measurements Using:
	Carrying Value		Fair Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Financial Assets:
Cash and cash equivalents	$	1,158,785	$	1,158,785	$	1,158,785	$	-	$	-
Deposits with banks and short-term investments		419,668		419,668		419,668		-		-
Cash deposited with clearing organizations and other segregated cash		29,030		29,030		29,030		-		-
Interest-bearing financing receivables		76,133		78,072		-		-		78,072
Interest-bearing deposits (included within investments)		456		456		456		-		-
Financial Liabilities:
Deposits and other customer payables	$	472,283	$	472,283	$	472,283	$	-	$	-
Senior debt		1,188,600		1,204,171		-		1,204,171		-

Fair Value of Certain Investments Based on NAV

The following tables present, at December 31, 2017 and 2016, certain investments that are valued using NAV or its equivalent as a practical expedient in determining fair value:

December 31, 2017

Estimated Liquidation Period of

Investments Not Redeemable

Investments

Redeemable

Fair Value

Unfunded

Commitments

% of

Fair Value

Not

Redeemable

5 Years

5-10

Years

Thereafter

Redemption

Frequency

Redemption

Notice Period

Alternative investment funds:

Hedge funds

2,517

(a)

<30-60 days

Funds of funds

528

(b)

<30-90 days

Other

595

(c)

<30-60 days

Debt funds

(d)

30 days

Equity funds

(e)

<30-90 days

Private equity funds:

Equity growth

76,679

10,300

(f)

100

Total

80,378

10,300

(a)	weekly (3%), monthly (5%) and quarterly (92%)

(b)	monthly (97%) and quarterly (3%)

(c)	daily (6%) and monthly (94%)

(d)	daily (100%)

(e)	daily (18%), monthly (50%) and quarterly (32%)

(f)	Unfunded commitments to private equity investments consolidated but not owned by Lazard of $5,902 are excluded. Such commitments are required to be funded by capital contributions from noncontrolling interest holders.

December 31, 2016

Estimated Liquidation Period of

Investments Not Redeemable

Investments

Redeemable

Fair Value

Unfunded

Commitments

% of

Fair Value

Not

Redeemable

5 Years

5-10

Years

Thereafter

Redemption

Frequency

Redemption

Notice Period

Alternative investment funds:

Hedge funds

6,190

(a)

<30-60 days

Funds of funds

492

(b)

<30-90 days

Other

443

(c)

<30-60 days

Debt funds

(d)

30 days

Equity funds

(e)

<30-90 days

Private equity funds:

Equity growth

90,824

9,183

(f)

100

Mezzanine debt

31,597

100

Total

129,591

9,183

(a)	weekly (73%), monthly (2%) and quarterly (25%)

(b)	monthly (98%) and quarterly (2%)

(c)	daily (7%) and monthly (93%)

(d)	daily (100%)

(e)	daily (19%), monthly (50%) and quarterly (31%)

(f)	Unfunded commitments to private equity investments consolidated but not owned by Lazard of $6,886 are excluded. Such commitments are required to be funded by capital contributions from noncontrolling interest holders.

Derivatives (Tables)

12 Months Ended

Dec. 31, 2017

Derivative Instruments And Hedging Activities Disclosure [Abstract]

Fair Values of Derivatives Reported on Consolidated Statements of Financial Condition

	December 31,
	2017		2016
Derivative Assets:
Forward foreign currency exchange rate contracts	$	3,314	$	1,993
Total return swaps and other (a)		418		-
	$	3,732	$	1,993
Derivative Liabilities:
Forward foreign currency exchange rate contracts	$	4,846	$	2,792
Total return swaps and other (a)		11,270		9,043
LFI and other similar deferred compensation arrangements		182,301		170,388
	$	198,417	$	182,223

(a)

Net Gains (Losses) with Respect to Derivative Instruments Not Designated as Hedging Instruments

	Year Ended December 31,
	2017			2016			2015
Forward foreign currency exchange rate contracts	$	(9,144	)	$	(2,253	)	$	15,773
LFI and other similar deferred compensation arrangements		(23,526	)		(3,318	)		3,827
Total return swaps and other		(15,709	)		(4,636	)		3,860
Total	$	(48,379	)	$	(10,207	)	$	23,460

Property (Tables)

12 Months Ended

Dec. 31, 2017

Property Plant And Equipment [Abstract]

Components of Property

At December 31, 2017 and 2016, property consisted of the following:

	Estimated
	Depreciable		December 31,
	Life in Years		2017		2016
Buildings		33	$	151,912	$	132,821
Leasehold improvements	3-20			173,102		175,810
Furniture and equipment	3-10			183,541		172,353
Construction in progress				14,573		14,038
Total				523,128		495,022
Less - Accumulated depreciation and amortization				317,827		286,001
Property			$	205,301	$	209,021

Goodwill and Other Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2017

Goodwill And Intangible Assets Disclosure [Abstract]

Components of Goodwill and Other Intangible Assets

The components of goodwill and other intangible assets at December 31, 2017 and 2016 are presented below:

	December 31,
	2017		2016
Goodwill	$	385,292	$	373,117
Other intangible assets (net of accumulated amortization)		6,072		8,907
	$	391,364	$	382,024

Changes in Carrying Amount of Goodwill

Changes in the carrying amount of goodwill for the years ended December 31, 2017, 2016 and 2015 are as follows:

	Year Ended December 31,
	2017		2016			2015
Balance, January 1	$	373,117	$	320,761		$	335,402
Business acquisitions		-		54,631			-
Foreign currency translation adjustments		12,175		(2,275	)		(14,641	)
Balance, December 31	$	385,292	$	373,117		$	320,761

Gross Cost and Accumulated Amortization of Other Intangible Assets

The gross cost and accumulated amortization of other intangible assets as of December 31, 2017 and 2016, by major intangible asset category, are as follows:

	December 31, 2017						December 31, 2016
	Gross Cost		Accumulated Amortization		Net Carrying Amount		Gross Cost		Accumulated Amortization		Net Carrying Amount
Success/incentive fees	$	35,422	$	29,723	$	5,699	$	35,259	$	26,984	$	8,275
Management fees, customer relationships and non-compete agreements		33,749		33,376		373		33,728		33,096		632
	$	69,171	$	63,099	$	6,072	$	68,987	$	60,080	$	8,907

Estimated Future Amortization Expense

Estimated future amortization expense is as follows:

Year Ending December 31,	Amortization Expense (a)
2018	$	2,941
2019		1,577
2020		1,554
Total amortization expense	$	6,072

(a)	Approximately 35% of intangible asset amortization is attributable to a noncontrolling interest.

Other Assets and Other Liabilities (Tables)

12 Months Ended

Dec. 31, 2017

Text Block [Abstract]

Schedule of Other Assets

The following table sets forth the Company’s other assets, by type, as of December 31, 2017 and 2016:

	December 31,
	2017		2016
Current tax receivables and other taxes	$	38,804	$	31,767
Prepaid compensation (see Note 14)		60,355		49,650
Other advances and prepayments		56,595		35,706
Other		72,390		67,376
Total	$	228,144	$	184,499

Schedule of Other Liabilities

The following table sets forth the Company’s other liabilities, by type, as of December 31, 2017 and 2016:

	December 31,
	2017		2016
Accrued expenses	$	155,551	$	124,721
Current income taxes and other taxes		123,548		99,278
Employee benefit-related liabilities		69,201		84,703
Deferred lease incentives		85,028		84,287
Unclaimed funds at LFB		14,962		24,997
Deferred revenue		45,390		35,717
Contingent consideration liability		28,941		22,608
Securities sold, not yet purchased		7,338		4,482
Other		43,629		56,653
Total	$	573,588	$	537,446

Senior Debt (Tables)

12 Months Ended

Dec. 31, 2017

Debt Disclosure [Abstract]

Senior Debt

Senior debt is comprised of the following as of December 31, 2017 and 2016:

							Outstanding as of
	Initial			Annual			December 31, 2017						December 31, 2016
	Principal Amount		Maturity Date	Interest Rate(b)			Principal		Unamortized Debt Costs		Carrying Value		Principal		Unamortized Debt Costs		Carrying Value
Lazard Group 2020 Senior Notes	$	500,000	11/14/20		4.25	%	$	500,000	$	2,647	$	497,353	$	500,000	$	3,569	$	496,431
Lazard Group 2025 Senior Notes (a)		400,000	2/13/25		3.75	%		400,000		3,361		396,639		400,000		3,833		396,167
Lazard Group 2027 Senior Notes (a)		300,000	3/1/27		3.625	%		300,000		3,609		296,391		300,000		3,998		296,002
Total							$	1,200,000	$	9,617	$	1,190,383	$	1,200,000	$	11,400	$	1,188,600

(a)

(b)

The effective interest rates of Lazard Group’s 4.25% senior notes due November 14, 2020 (the “2020 Notes”), the 2025 Notes and the 2027 Notes are 4.43%, 3.87% and 3.76%, respectively.

Debt Maturities Relating to Senior Borrowings Outstanding

Debt maturities relating to senior borrowings outstanding at December 31, 2017 for each of the five years in the period ending December 31, 2022 and thereafter are set forth in the table below.

Year Ending December 31,
2018 - 2019	$	-
2020		500,000
2021 - 2022		-
Thereafter		700,000
Total	$	1,200,000

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2017

Commitments And Contingencies Disclosure [Abstract]

Schedule of Future Minimum Rental Payment for Operating Leases

At December 31, 2017, minimum rental commitments under non-cancelable operating leases, net of sublease income, are approximately as follows:


Year Ending December 31,
2018	$	83,851
2019		73,889
2020		69,845
2021		67,118
2022		56,268
Thereafter		442,438
Total minimum lease payments		793,409
Less sublease proceeds		36,141
Net lease payments	$	757,268

Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2017

Equity [Abstract]

Schedule of Share Repurchase Authorized by Board of Directors

Share Repurchase Program—During the year ended December 31, 2017 and since 2014, the Board of Directors of Lazard authorized the repurchase of Class A common stock as set forth in the table below.

Date	Repurchase Authorization		Expiration
April 2014	$	200,000	December 31, 2015
February 2015	$	150,000	December 31, 2016
January 2016	$	200,000	December 31, 2017
April 2016	$	113,182	December 31, 2017
November 2016	$	236,000	December 31, 2018
October 2017	$	200,000	December 31, 2019

Schedule of Shares Repurchased Under the Share Repurchase Program

Years Ended December 31:	Number of Shares Purchased		Average Price Per Share
2015		3,438,789	$	50.24
2016		8,551,271	$	35.11
2017		6,956,097	$	44.10

Accumulated Other Comprehensive Income (Loss), Net of Tax

	Currency Translation Adjustments			Employee Benefit Plans			Total AOCI			Amount Attributable to Noncontrolling Interests			Total Lazard Ltd AOCI
Balance, January 1, 2017	$	(155,204	)	$	(159,020	)	$	(314,224	)	$	(2	)	$	(314,222	)
Activity January 1 to December 31, 2017:
Other comprehensive income before reclassifications		71,669			2,085			73,754			1			73,753
Adjustments for items reclassified to earnings, net of tax					7,951			7,951						7,951
Net other comprehensive income		71,669			10,036			81,705			1			81,704
Balance, December 31, 2017	$	(83,535	)	$	(148,984	)	$	(232,519	)	$	(1	)	$	(232,518	)

	Currency Translation Adjustments			Employee Benefit Plans			Total AOCI			Amount Attributable to Noncontrolling Interests			Total Lazard Ltd AOCI
Balance, January 1, 2016	$	(97,284	)	$	(137,073	)	$	(234,357	)	$	(1	)	$	(234,356	)
Activity January 1 to December 31, 2016:
Other comprehensive loss before reclassifications		(57,920	)		(24,473	)		(82,393	)		(1	)		(82,392	)
Adjustments for items reclassified to earnings, net of tax		-			2,526			2,526			-			2,526
Net other comprehensive loss		(57,920	)		(21,947	)		(79,867	)		(1	)		(79,866	)
Balance, December 31, 2016	$	(155,204	)	$	(159,020	)	$	(314,224	)	$	(2	)	$	(314,222	)

	Currency Translation Adjustments			Employee Benefit Plans			Total AOCI			Amount Attributable to Noncontrolling Interests			Total Lazard Ltd AOCI
Balance, January 1, 2015	$	(46,102	)	$	(154,665	)	$	(200,767	)	$	(1	)	$	(200,766	)
Activity January 1 to December 31, 2015:
Other comprehensive income (loss) before reclassifications		(51,182	)		11,283			(39,899	)		-			(39,899	)
Adjustments for items reclassified to earnings, net of tax		-			6,309			6,309			-			6,309
Net other comprehensive income (loss)		(51,182	)		17,592			(33,590	)		-			(33,590	)
Balance, December 31, 2015	$	(97,284	)	$	(137,073	)	$	(234,357	)	$	(1	)	$	(234,356	)

Adjustments for Items Reclassified Out of AOCI

The table below reflects adjustments for items reclassified out of AOCI, by component, for the years ended December 31, 2017, 2016 and 2015:

	Year Ended December 31,
	2017		2016		2015
Amortization relating to employee benefit plans (a)	$	10,171	$	4,283	$	7,816
Less - related income taxes		2,220		1,757		1,507
Total reclassifications, net of tax	$	7,951	$	2,526	$	6,309

(a)	Included in the computation of net periodic benefit cost (see Note 15). Such amounts are included in “compensation and benefits” expense on the consolidated statements of operations.

Net Income Attributable to Noncontrolling Interests

	Net Income Attributable to Noncontrolling Interests Year Ended December 31,
	2017		2016		2015
Edgewater	$	6,259	$	5,992	$	6,557
Other		5		2		2
Total	$	6,264	$	5,994	$	6,559

	Noncontrolling Interests as of December 31,
	2017		2016
Edgewater	$	58,568	$	57,238
Other		534		588
Total	$	59,102	$	57,826

Incentive Plans (Tables)

12 Months Ended

Dec. 31, 2017

Summary of Impact of Share-Based Incentive Plans on Compensation and Benefits Expense

	Year Ended December 31,
	2017		2016		2015
Share-based incentive awards:
RSUs	$	190,821	$	171,188	$	166,395
PRSUs		40,767		43,018		36,529
Restricted Stock		39,369		45,536		22,342
DSUs		2,008		1,720		1,457
Total	$	272,965	$	261,462	$	226,723

Schedule of Issuance of RSUs and Charges to Retained Earnings

During the years ended December 31, 2017, 2016 and 2015, issuances of RSUs pertaining to such dividend participation rights and respective charges to “retained earnings”, net of estimated forfeitures (with corresponding credits to “additional paid-in-capital”), consisted of the following:

	Year Ended December 31,
	2017		2016		2015
Number of RSUs issued		985,584		1,085,354		693,714
Charges to retained earnings, net of estimated forfeitures	$	41,746	$	37,284	$	34,255

Summary of LFI and Other Similar Deferred Compensation Arrangements

The following is a summary of activity relating to LFI and other similar deferred compensation arrangements during the years ended December 31, 2017 and 2016:

	Prepaid Compensation Asset			Compensation Liability
Balance, January 1, 2017	$	49,650		$	170,388
Granted		77,580			77,580
Settled		-			(96,025	)
Forfeited		(992	)		(1,819	)
Amortization		(67,575	)		-
Change in fair value related to:
Increase in fair value of underlying investments		-			23,526
Adjustment for estimated forfeitures		-			6,634
Other		1,692			2,017
Balance, December 31, 2017	$	60,355		$	182,301

	Prepaid Compensation Asset			Compensation Liability
Balance, January 1, 2016	$	75,703		$	193,574
Granted		52,121			52,121
Settled		-			(77,457	)
Forfeited		(2,942	)		(5,380	)
Amortization		(73,340	)		-
Change in fair value related to:
Increase in fair value of underlying investments		-			3,318
Adjustment for estimated forfeitures		-			4,671
Other		(1,892	)		(459	)
Balance, December 31, 2016	$	49,650		$	170,388

	Year Ended Ended December 31,
	2017		2016		2015
Amortization, net of forfeitures	$	73,382	$	75,573	$	85,563
Change in the fair value of underlying investments		23,526		3,318		(3,827	)
Total	$	96,908	$	78,891	$	81,736

Restricted Stock Units and Deferred Stock Units [Member]

Schedule of Activity Relating to Share-based Awards

The following is a summary of activity relating to RSUs and DSUs during the three-year period ended December 31, 2017:

	RSUs					DSUs
	Units			Weighted Average Grant Date Fair Value		Units			Weighted Average Grant Date Fair Value
Balance, January 1, 2015		13,529,116		$	35.19		286,227		$	34.21
Granted (including 693,714 RSUs relating to dividend participation)		4,296,386		$	48.57		26,443		$	55.11
Forfeited		(469,776	)	$	43.54		-			-
Vested		(7,756,068	)	$	31.12		-			-
Balance, December 31, 2015		9,599,658		$	44.06		312,670		$	35.98
Granted (including 1,085,354 RSUs relating to dividend participation)		6,878,306		$	34.86		48,814		$	35.23
Forfeited		(239,432	)	$	39.53		-			-
Vested		(4,540,394	)	$	39.16		(84,759	)	$	35.30
Balance, December 31, 2016		11,698,138		$	40.65		276,725		$	36.05
Granted (including 985,584 RSUs relating to dividend participation)		5,437,591		$	43.03		45,162		$	44.46
Forfeited		(217,720	)	$	40.20		-			-
Vested		(3,998,163	)	$	45.26		(43,465	)	$	35.77
Balance, December 31, 2017		12,919,846		$	40.23		278,422		$	37.46

Restricted Stock Awards Class A [Member]

Schedule of Activity Relating to Share-based Awards

The following is a summary of activity related to shares of restricted Class A common stock associated with compensation arrangements during the three-year period ended December 31, 2017:

	Restricted Shares			Weighted Average Grant Date Fair Value
Balance, January 1, 2015		729,827		$	38.63
Granted		576,886		$	50.88
Forfeited		(45,851	)	$	50.17
Vested		(547,124	)	$	39.50
Balance, December 31, 2015		713,738		$	47.12
Granted		1,795,258		$	36.76
Forfeited		(34,051	)	$	40.48
Vested		(819,872	)	$	37.16
Balance, December 31, 2016		1,655,073		$	40.95
Granted		841,355		$	42.58
Forfeited		(66,592	)	$	40.80
Vested		(491,676	)	$	45.35
Balance, December 31, 2017		1,938,160		$	40.54

PRSUs [Member]

Schedule of Activity Relating to Share-based Awards

The following is a summary of activity relating to PRSUs during the three-year period ended December 31, 2017:

	PRSUs			Weighted Average Grant Date Fair Value
Balance, January 1, 2015		1,347,148		$	37.79
Granted (a)		368,389		$	52.85
Vested		(696,499	)	$	35.96
Balance, December 31, 2015		1,019,038		$	44.49
Granted (a)		627,956		$	32.91
Performance units earned (b)		360,783		$	41.20
Vested		(417,021	)	$	38.43
Balance, December 31, 2016		1,590,756		$	40.76
Granted (a)		458,113		$	43.76
Performance units earned (b)		368,389		$	47.74
Vested		(825,565	)	$	42.27
Balance, December 31, 2017		1,591,693		$	42.46

(a)	Represents PRSU awards granted during the relevant year at the target payout level.

(b)	Represents shares of Class A common stock earned during the fiscal year under the performance criteria of previously-granted PRSU awards in excess of the target payout level of such awards.

- Definition

Tabular disclosure of an equity-based arrangement (such as stock or unit options and stock or unit awards) with an individual employee, which is generally an employment contract between the entity and a selected officer or key employee containing a promise by the employer to pay certain equity-based awards at future dates, sometimes including a period after retirement, upon compliance with stipulated requirements. This type of arrangement is distinguished from broader based employee benefit plans as it is usually tailored to the employee. Disclosure also typically includes the amount of related compensation expense recognized during the reporting period, the number of shares or units issued during the period under such arrangements, and the carrying amount as of the balance sheet date of the related liability.

+ References + Details

Employee Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2017

Compensation And Retirement Disclosure [Abstract]

Summary of Changes in Benefit Obligations, Fair Value of Assets, Funded Status and Amounts Recognized in Consolidated Statements of Financial Condition

	Pension Plans						Medical Plan
	2017			2016			2017		2016
Change in benefit obligation
Benefit obligation at beginning of year	$	718,821		$	694,187		$	-	$	4,750
Service cost		1,413			1,235					11
Interest cost		16,240			19,871					167
Actuarial (gain) loss		2,702			135,164					(1,639	)
Benefits paid		(44,589	)		(31,904	)				(3,289	)
Foreign currency translation and other adjustments		69,244			(99,732	)
Benefit obligation at end of year		763,831			718,821			-		-
Change in plan assets
Fair value of plan assets at beginning of year		646,119			656,084
Actual return on plan assets		43,624			119,287
Employer contributions		16,844			11,343					3,289
Benefits paid		(42,022	)		(29,384	)				(3,289	)
Foreign currency translation and other adjustments		63,716			(111,211	)
Fair value of plan assets at end of year		728,281			646,119			-		-
Funded (deficit) at end of year	$	(35,550	)	$	(72,702	)	$	-	$	-
Amounts recognized in the consolidated statements of financial condition at December 31, 2017 and 2016 consist of:
Prepaid pension asset (included in “other assets”)	$	16,189		$	822		$	-	$	-
Accrued benefit liability (included in “other liabilities”)		(51,739	)		(73,524	)
Net amount recognized	$	(35,550	)	$	(72,702	)	$	-	$	-
Amounts recognized in AOCI (excluding tax benefits of $35,154 and $33,864 at December 31, 2017 and 2016, respectively) consist of:
Actuarial net loss (gain)	$	184,135		$	192,855		$	-	$	-
Prior service cost		-			30
Net amount recognized	$	184,135		$	192,885		$	-	$	-

Summary of Fair Value of Plan Assets, Accumulated Benefit Obligation and Projected Benefit Obligation

The following table summarizes the fair value of plan assets, the accumulated benefit obligation and the projected benefit obligation at December 31, 2017 and 2016:

	U.S. Pension Plans				Non-U.S. Pension Plans				Total
	As Of December 31,				As Of December 31,				As Of December 31,
	2017		2016		2017		2016		2017		2016
Fair value of plan assets	$	24,644	$	22,161	$	703,637	$	623,958	$	728,281	$	646,119
Accumulated benefit obligation	$	35,376	$	33,868	$	728,455	$	684,953	$	763,831	$	718,821
Projected benefit obligation	$	35,376	$	33,868	$	728,455	$	684,953	$	763,831	$	718,821

Components of Net Periodic Benefit Cost (Credit)

	Pension Plans									Medical Plan
	For The Year Ended									For The Year Ended
	December 31,									December 31,
	2017			2016			2015			2017		2016			2015
Components of Net Periodic Benefit Cost (Credit):
Service cost	$	1,413		$	1,235		$	1,530		$	-	$	11		$	27
Interest cost		16,240			19,871			24,600			-		167			179
Expected return on plan assets		(25,300	)		(27,337	)		(28,301	)		-		-			-
Amortization of:
Prior service cost		30			2,369			2,376			-		-			-
Net actuarial loss (gain)		10,141			3,888			5,440			-		(185	)		-
Settlement loss (gain)		807			-			-			-		(1,788	)		-
Net periodic benefit cost (credit)	$	3,331		$	26		$	5,645		$	-	$	(1,795	)	$	206


Actual return on plan assets	$	43,624		$	119,287		$	9,873
Employer contributions	$	16,844		$	11,343		$	39,301		$	-	$	3,289		$	276
Benefits paid	$	42,022		$	29,384		$	32,321		$	-	$	3,289		$	276
Other changes in plan assets and benefit obligations recognized in AOCI (excluding tax expense (benefit) of $(1,287), $(3,448) and $7,151 during the years ended December 31, 2017, 2016 and 2015, respectively):
Net actuarial (gain) loss	$	(17,357	)	$	51,626		$	(4,650	)	$	-	$	(1,638	)	$	(695	)
Reclassification of prior service (cost) credit to earnings		(30	)		(2,369	)		(2,376	)		-		-			-
Reclassification of actuarial gain (loss) to earnings		(10,141	)		(3,888	)		(5,440	)		-		1,973			-
Currency translation and other adjustments		18,778			(20,309	)		(11,582	)		-		-			-
Total recognized in AOCI	$	(8,750	)	$	25,060		$	(24,048	)	$	-	$	335		$	(695	)
Net amount recognized in total periodic benefit cost and AOCI	$	(5,419	)	$	25,086		$	(18,403	)	$	-	$	(1,460	)	$	(489	)

Schedule of Amounts in AOCI on Consolidated Statement of Financial Condition Expected to be Recognized

Pension

Plans

Net actuarial loss

5,072

Schedule of Assumptions Used to Develop Actuarial Present Value of Projected Benefit Obligation and Net Periodic Pension Cost

	Pension Plans									Medical Plan
	December 31,									December 31,
	2017			2016			2015			2017		2016			2015
Weighted average assumptions used to determine benefit obligations:
Discount rate		2.3	%		2.5	%		3.5	%		-		-			3.9	%
Weighted average assumptions used to determine net periodic benefit cost:
Discount rate		2.2	%		1.9	%		2.6	%		-		3.9	%		3.7	%
Expected long-term rate of return on plan assets		3.8	%		4.6	%		4.3	%		-		-			-
Healthcare cost trend rates used to determine net periodic benefit cost:
Initial											-		6.5	%		7.0	%
Ultimate											-		5.0	%		5.0	%
Year ultimate trend rate achieved											-	2019			2019

Schedule of Expected Benefit Payments

	Pension
	Plans
2018	$	24,631
2019		25,347
2020		25,351
2021		26,981
2022		29,287
2023-2027		153,490

Schedule of Categorization of Plans' Assets

	As of December 31, 2017
	Level 1		Level 2		Level 3		NAV (a)		Total
Assets:
Cash	$	11,544	$	-	$	-	$	-	$	11,544
Debt		73,728		-		-		-		73,728
Equities		36,854		-		-		-		36,854
Funds:
Alternative investments		-		-		-		25,938		25,938
Debt		11,002		-		-		363,915		374,917
Equity		192,875		3,746		-		8,015		204,636
Derivative		-		664		-		-		664
Total	$	326,003	$	4,410	$	-	$	397,868	$	728,281

	As of December 31, 2016
	Level 1		Level 2		Level 3		NAV (a)		Total
Assets:
Cash	$	23,341	$	-	$	-	$	-	$	23,341
Debt		63,431		-		-		-		63,431
Equities		29,287		-		-		-		29,287
Funds:
Alternative investments		1,216		-		-		23,062		24,278
Debt		10,494		-		-		320,560		331,054
Equity		167,981		-		-		6,129		174,110
Derivative		-		618		-		-		618
Total	$	295,750	$	618	$	-	$	349,751	$	646,119

(a)	Represents certain investments measured at NAV or its equivalent as a practical expedient in determining fair value. In accordance with current accounting guidance, these investments have not been classified in the fair value hierarchy.

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Schedule of Provision (Benefit) for Income Taxes

	Year Ended December 31,
	2017			2016		2015
Current:
Federal	$	349		$	1,766	$	8,177
Foreign		64,119			54,253		78,086
State and local (primarily UBT)		(32	)		4,090		4,970
Total current		64,436			60,109		91,233
Deferred:
Federal		480,085			50,602		(988,900	)
Foreign		12,928			1,354		(3,960	)
State and local		8,150			11,704		(107,925	)
Total deferred		501,163			63,660		(1,100,785	)
Total	$	565,599		$	123,769	$	(1,009,552	)

Schedule of Reconciliation of U.S. Federal Statutory Income Tax Rate to Effective Tax Rates

	Year Ended December 31,
	2017			2016			2015
U.S. federal statutory income tax rate		35.0	%		35.0	%		35.0	%
U.S. tax reform		43.4			-			-
Foreign source income not subject to U.S. income tax		(4.2	)		(9.3	)		419.4
Change in U.S. federal valuation allowance		(3.4	)		(3.6	)		5477.0
Share-based incentive compensation		(4.0	)		-			-
Foreign taxes		(0.2	)		(0.1	)		(361.6	)
State and local taxes		2.4			3.0			522.2
Income of non-controlling interests		(0.3	)		(0.3	)		13.8
Other, net		(0.2	)		(0.8	)		(31.5	)
Effective income tax rate (a)		68.5	%		23.9	%		6074.3	%

(a)

Schedule of Deferred Tax Assets and Liabilities

Details of the Company’s deferred tax assets and liabilities are as follows:

	December 31,
	2017			2016
Deferred Tax Assets:
Basis adjustments (a)	$	339,133		$	692,430
Compensation and benefits		175,456			197,750
Net operating loss and tax credit carryforwards		239,959			285,694
Depreciation and amortization		1,537			850
Other		34,615			53,895
Gross deferred tax assets		790,700			1,230,619
Valuation allowance		(61,456	)		(69,593	)
Deferred tax assets (net of valuation allowance)		729,244			1,161,026
Deferred Tax Liabilities:
Depreciation and amortization		17,257			26,539
Compensation and benefits		23,251			5,447
Goodwill		21,749			27,932
Other		26,134			34,499
Deferred tax liabilities		88,391			94,417
Net deferred tax assets	$	640,853		$	1,066,609

(a)	The basis adjustments recorded as of December 31, 2017 and 2016 are primarily the result of additional basis from acquisitions of interests, including the impact of the tax receivable agreement obligation.

Summary of Changes in Deferred Tax Assets Valuation Allowance

Changes in the deferred tax assets valuation allowance for the years ended December 31, 2017, 2016 and 2015 was as follows:

	Year Ended December 31,
	2017			2016			2015
Beginning Balance	$	69,593		$	89,251		$	1,044,152
Credited to provision (benefit) for income taxes		(23,670	)		(15,981	)		(954,487	)
Charged (credited) to other comprehensive income and other (a)		15,533			(3,677	)		(414	)
Ending Balance	$	61,456		$	69,593		$	89,251

(a)

Schedule of Gross Unrecognized Tax Benefits

A reconciliation of the beginning to the ending amount of gross unrecognized tax benefits (excluding interest and penalties) for the years ended December 31, 2017, 2016 and 2015 is as follows:

	Year Ended December 31,
	2017			2016			2015
Balance, January 1 (excluding interest and penalties of $15,392, $13,083 and $13,004, respectively)	$	78,396		$	77,280		$	68,224
Increases in gross unrecognized tax benefits relating to tax positions taken during:
Prior years		1,598			5,891			-
Current year		19,823			18,438			22,212
Decreases in gross unrecognized tax benefits relating to:
Tax positions taken during prior years		(2,961	)		(5,316	)		(621	)
Settlements with tax authorities		-			(1,706	)		-
Lapse of the applicable statute of limitations		(18,182	)		(16,191	)		(12,535	)
Balance, December 31 (excluding interest and penalties of $15,136, $15,392 and $13,083, respectively)	$	78,674		$	78,396		$	77,280

Schedule of Additional Information Relating to Unrecognized Tax Benefits

Additional information with respect to unrecognized tax benefits is as follows:

	Year Ended December 31,
	2017			2016		2015
Unrecognized tax benefits at the end of the year that, if recognized, would favorably affect the effective tax rate (includes interest and penalties of $15,136, $15,392 and $13,083, respectively)	$	78,841		$	81,564	$	74,785
Unrecognized tax benefits that, if recognized, would not affect the effective tax rate	$	14,969		$	12,224	$	15,578
Interest and penalties recognized in current income tax expense (after giving effect to the reversal of interest and penalties of $6,185, $3,143 and $3,865, respectively)	$	(256	)	$	2,309	$	79

Net Income Per Share of Class A Common Stock (Tables)

12 Months Ended

Dec. 31, 2017

Earnings Per Share [Abstract]

Company's Basic and Diluted Net Income Per Share and Weighted Average Shares Outstanding

The calculations of the Company’s basic and diluted net income per share and weighted average shares outstanding for the years ended December 31, 2017, 2016 and 2015 are presented below:

	Year Ended December 31,
	2017		2016		2015
Net income attributable to Lazard Ltd - basic	$	253,583	$	387,698	$	986,373
Net income attributable to Lazard Ltd - diluted	$	253,583	$	387,698	$	986,373
Weighted average number of shares of Class A common stock outstanding		121,309,174		124,635,160		125,294,261
Add - adjustment for shares of Class A common stock issuable on a non-contingent basis		264,268		135,241		72,011
Weighted average number of shares of Class A common stock outstanding - basic		121,573,442		124,770,401		125,366,272
Add - dilutive effect, as applicable, of:
Weighted average number of incremental shares of Class A common stock issuable from share-based incentive compensation		10,906,286		7,863,229		7,878,274
Weighted average number of shares of Class A common stock outstanding - diluted		132,479,728		132,633,630		133,244,546
Net income attributable to Lazard Ltd per share of Class A common stock:
Basic	$	2.09	$	3.11	$	7.87
Diluted	$	1.91	$	2.92	$	7.40

Segment Information (Tables)

12 Months Ended

Dec. 31, 2017

Segment Reporting [Abstract]

Segment's Contribution with Respect to Net Revenue, Operating Expenses, Operating Income (Loss) and Total Assets

		As Of Or For The Year Ended December 31,
		2017			2016			2015
Financial Advisory	Net Revenue	$	1,387,682		$	1,301,044		$	1,279,628
	Operating Expenses (a)		1,143,586			1,017,055			1,005,837
	Operating Income	$	244,096		$	283,989		$	273,791
	Total Assets	$	843,142		$	907,035		$	763,374
Asset Management	Net Revenue	$	1,255,820		$	1,051,316		$	1,111,105
	Operating Expenses (a)		810,870			769,737			736,798
	Operating Income	$	444,950		$	281,579		$	374,307
	Total Assets	$	756,398		$	645,653		$	640,034
Corporate	Net Revenue	$	809		$	(18,989	)	$	(37,125	)
	Operating Expenses (a)/(b)		(135,591	)		29,118			627,593
	Operating Income (Loss)	$	136,400		$	(48,107	)	$	(664,718	)
	Total Assets	$	3,329,137		$	3,003,820		$	3,074,366
Total	Net Revenue	$	2,644,311		$	2,333,371		$	2,353,608
	Operating Expenses (a)		1,818,865			1,815,910			2,370,228
	Operating Income (Loss)	$	825,446		$	517,461		$	(16,620	)
	Total Assets	$	4,928,677		$	4,556,508		$	4,477,774

(a)	Operating expenses include depreciation and amortization of property as set forth in table below.

	Year Ended December 31,
	2017		2016		2015
Financial Advisory	$	6,596	$	5,661	$	4,412
Asset Management		2,830		3,666		2,957
Corporate		22,072		23,937		25,416
Total	$	31,498	$	33,264	$	32,785

(b)

Schedule of Operating Income, Revenue and Identifiable Assets by Geographical Areas

The following table sets forth the net revenue from, and identifiable assets for, the Company and its consolidated subsidiaries by geographic region allocated on the basis described above.

	As Of Or For The Year Ended December 31,
	2017		2016		2015
Net Revenue:
Americas	$	1,558,070	$	1,399,285	$	1,322,898
EMEA		903,525		795,932		813,136
Asia Pacific		182,716		138,154		217,574
Total	$	2,644,311	$	2,333,371	$	2,353,608
Operating Income (Loss):
Americas (a)	$	596,044	$	335,887	$	(259,538	)
EMEA		193,781		168,745		163,612
Asia Pacific		35,621		12,829		79,306
Total	$	825,446	$	517,461	$	(16,620	)
Identifiable Assets:
Americas	$	2,600,412	$	3,015,267	$	2,811,850
EMEA		2,039,385		1,286,149		1,405,555
Asia Pacific		288,880		255,092		260,369
Total	$	4,928,677	$	4,556,508	$	4,477,774

(a)

Supplemental Financial Information - Quarterly Results (Tables)

12 Months Ended

Dec. 31, 2017

Quarterly Financial Information Disclosure [Abstract]

Schedule of Quarterly Financial Information

	2017 Fiscal Quarter
	First		Second		Third		Fourth			Year
	(dollars in thousands, except per share data)
Net revenue	$	623,464	$	717,180	$	624,859	$	678,808		$	2,644,311
Operating expenses		473,267		544,679		480,647		320,272			1,818,865
Operating income	$	150,197	$	172,501	$	144,212	$	358,536		$	825,446
Net income (loss)	$	110,430	$	120,901	$	111,470	$	(82,954	)	$	259,847
Less - net income attributable to noncontrolling interests		2,877		523		2,260		604			6,264
Net income (loss) attributable to Lazard Ltd	$	107,553	$	120,378	$	109,210	$	(83,558	)	$	253,583
Attributable to Lazard Ltd Class A common stockholders:
Net income per share of common stock:
Basic	$	0.88	$	0.98	$	0.90	$	(0.70	)	$	2.09
Diluted	$	0.81	$	0.91	$	0.82	$	(0.70	)	$	1.91
Dividends declared per share of common stock	$	1.58	$	0.41	$	0.41	$	0.41		$	2.81

	2016 Fiscal Quarter
	First		Second		Third		Fourth		Year
	(dollars in thousands, except per share data)
Net revenue	$	498,218	$	534,680	$	608,908	$	691,565	$	2,333,371
Operating expenses		399,841		421,444		459,916		534,709		1,815,910
Operating income	$	98,377	$	113,236	$	148,992	$	156,856	$	517,461
Net income	$	70,723	$	81,364	$	112,618	$	128,987	$	393,692
Less - net income attributable to noncontrolling interests		3,900		1,007		82		1,005		5,994
Net income attributable to Lazard Ltd	$	66,823	$	80,357	$	112,536	$	127,982	$	387,698
Attributable to Lazard Ltd Class A common stockholders:
Net income per share of common stock:
Basic	$	0.53	$	0.64	$	0.90	$	1.04	$	3.11
Diluted	$	0.50	$	0.61	$	0.85	$	0.96	$	2.92
Dividends declared per share of common stock	$	1.55	$	0.38	$	0.38	$	0.38	$	2.69

Organization and Basis of Presentation - Additional Information (Detail) - Segment	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Organization And Basis Of Presentation [Line Items]
Governing operating agreement, date	Oct. 26, 2015
Number of business segments	2
Lazard Group LLC [Member]
Organization And Basis Of Presentation [Line Items]
Percentage of common membership interests held	100.00%	100.00%

Significant Accounting Policies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Significant Accounting Policies [Line Items]
Foreign currency remeasurement gains (losses), net of hedge transactions	$ 1,900,000	$ (1,153,000)	$ 1,589,000
Depreciation and amortization expense	$ 31,498,000	33,264,000	32,785,000
Annual date of goodwill impairment	Nov. 01, 2017
Goodwill impairment loss	$ 0	0	0
Recoverable expenses	17,793,000	16,998,000	19,358,000
Soft dollar arrangement expenses	$ 24,000,000
Operating Segments [Member] \| Financial Advisory Segment [Member]
Significant Accounting Policies [Line Items]
Fees receivable outstanding past due	60 days from the date of invoice
Contractual payment term description relating to our interest-bearing financing receivables	Financial Advisory transactions include specific contractual payment terms that may vary from one month to four years (as is the case for our interest-bearing financing receivables) following the invoice date or may be subject to court approval (as is the case with bankruptcy-related restructuring assignments). In such cases, receivables are deemed past due when payment is not received by the agreed-upon contractual date or the court approval date, respectively.
Period receivables past due in excess of 180 days are fully provided unless there is evidence that the balance is collectible	180 days
Depreciation and amortization expense	$ 6,596,000	5,661,000	4,412,000
Operating Segments [Member] \| Asset Management Segment [Member]
Significant Accounting Policies [Line Items]
Fees receivable outstanding past due	12 months after the invoice date
Depreciation and amortization expense	$ 2,830,000	$ 3,666,000	$ 2,957,000

Recent Accounting Developments - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jan. 01, 2017	Dec. 31, 2014
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred tax assets, valuation allowance		$ 61,456	$ 69,593	$ 89,251		$ 1,044,152
U.S. federal statutory income tax rate		35.00%	35.00%	35.00%
Scenario Forecast [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
U.S. federal statutory income tax rate	21.00%
Adjustments for New Accounting Principle [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred tax assets recorded for previously unrecognized excess tax benefits on share-based payment awards					$ 81,544
Deferred tax assets, valuation allowance					$ 12,090

Receivables - Schedule of Activity in Allowance for Doubtful Accounts (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Allowance For Doubtful Accounts Receivable Rollforward
Allowance for doubtful accounts receivables, Beginning balance	$ 16,386	$ 12,882	$ 23,540
Bad debt expense, net of recoveries	15,419	10,055	3,125
Charge-offs, foreign currency translation and other adjustments	(8,059)	(6,551)	(13,783)
Allowance for doubtful accounts receivables, Ending balance	$ 23,746	$ 16,386	$ 12,882

Receivables - Additional Information (Detail) - USD ($)	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivables past due or deemed uncollectible	$ 34,865,000	$ 22,212,000
Interest-bearing financing fee receivables	80,536,000	76,133,000
Allowance for doubtful accounts receivables	23,746,000	16,386,000	$ 12,882,000	$ 23,540,000
Aggregate carrying amount of non-interest bearing receivables	491,080,000	562,149,000
Financing Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for doubtful accounts receivables	$ 0	$ 0

Investments - Company's Investments and Securities Sold, Not Yet Purchased (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Schedule of Investments [Line Items]
Total investments	$ 427,186	$ 459,422
Equity method		222
Investments, at fair value	426,630	458,744
Securities sold, not yet purchased, at fair value (included in "other liabilities")	7,338	4,482
Interest-bearing Deposits [Member]
Schedule of Investments [Line Items]
Total investments	556	456
Debt [Member]
Schedule of Investments [Line Items]
Total investments	6
Investments, at fair value	6
Equities [Member]
Schedule of Investments [Line Items]
Total investments	45,257	41,017
Investments, at fair value	45,257	41,017
Alternative Investment Funds [Member]
Schedule of Investments [Line Items]
Total investments	20,993	32,441
Investments, at fair value	20,993	32,441
Debt Funds [Member]
Schedule of Investments [Line Items]
Total investments	84,077	74,597
Investments, at fair value	84,077	74,597
Equity Funds [Member]
Schedule of Investments [Line Items]
Total investments	199,618	188,268
Investments, at fair value	199,618	188,268
Private Equity Funds [Member]
Schedule of Investments [Line Items]
Total investments	76,679	122,421
Investments, at fair value	76,679	122,421
Funds Total [Member]
Schedule of Investments [Line Items]
Total investments	$ 381,367	$ 417,727

Investments - Company's Investments and Securities Sold, Not Yet Purchased (Parenthetical) (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Schedule of Investments [Line Items]
Investments	$ 427,186	$ 459,422
Alternative Investment Funds [Member]
Schedule of Investments [Line Items]
Investments	20,993	32,441
Alternative Investment Funds [Member] \| Lazard Fund Interests [Member]
Schedule of Investments [Line Items]
Investments	11,213	13,080
Debt Funds [Member]
Schedule of Investments [Line Items]
Investments	84,077	74,597
Debt Funds [Member] \| Lazard Fund Interests [Member]
Schedule of Investments [Line Items]
Investments	48,391	37,869
Equity Funds [Member]
Schedule of Investments [Line Items]
Investments	199,618	188,268
Equity Funds [Member] \| Lazard Fund Interests [Member]
Schedule of Investments [Line Items]
Investments	$ 131,893	$ 128,219

Investments - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2015
Schedule of Investments [Line Items]
Revenue relating to disposal of business		$ 24,388
Minimum [Member] \| Interest-bearing Deposits [Member]
Schedule of Investments [Line Items]
Interest-bearing deposits maturity period	3 months
Maximum [Member] \| Interest-bearing Deposits [Member]
Schedule of Investments [Line Items]
Interest-bearing deposits maturity period	1 year

Investments - Schedule of Trading Securities Net Unrealized Investment Gains and Losses (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net Realized Or Unrealized Gain Loss On Trading Securities [Abstract]
Net unrealized investment gains (losses)	$ 27,192	$ 11,816	$ (19,681)

Fair Value Measurements - Schedule of Classification of Investments and Certain Other Assets and Liabilities Measured at Fair Value on Recurring Basis and Investments Measured at NAV (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	$ 426,630	$ 458,744
Total Derivative Assets	3,732	1,993
Total investments measured at fair value	430,362	460,737
Securities sold, not yet purchased	7,338	4,482
Contingent consideration liability	28,941	22,608
Total Derivative Liabilities	198,417	182,223
Total of Liabilities Measured at Fair Value	234,696	209,313
Fair Value, Measurements, Recurring [Member] \| NAV [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total investments measured at fair value	80,378	129,591
Level 1 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total investments measured at fair value	344,660	327,645
Securities sold, not yet purchased	7,338	4,482
Total of Liabilities Measured at Fair Value	7,338	4,482
Level 2 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total Derivative Assets	3,732	1,993
Total investments measured at fair value	3,732	1,993
Total Derivative Liabilities	198,417	182,223
Total of Liabilities Measured at Fair Value	198,417	182,223
Level 3 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total investments measured at fair value	1,592	1,508
Contingent consideration liability	28,941	22,608
Total of Liabilities Measured at Fair Value	28,941	22,608
Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	6
Debt [Member] \| Level 1 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	6
Equities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	45,257	41,017
Equities [Member] \| Level 1 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	43,665	39,509
Equities [Member] \| Level 3 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	1,592	1,508
Alternative Investment Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	20,993	32,441
Alternative Investment Funds [Member] \| Fair Value, Measurements, Recurring [Member] \| NAV [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	3,640	7,125
Alternative Investment Funds [Member] \| Level 1 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	17,353	25,316
Debt Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	84,077	74,597
Debt Funds [Member] \| Fair Value, Measurements, Recurring [Member] \| NAV [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	6	6
Debt Funds [Member] \| Level 1 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	84,071	74,591
Equity Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	199,618	188,268
Equity Funds [Member] \| Fair Value, Measurements, Recurring [Member] \| NAV [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	53	39
Equity Funds [Member] \| Level 1 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	199,565	188,229
Private Equity Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	76,679	122,421
Private Equity Funds [Member] \| Fair Value, Measurements, Recurring [Member] \| NAV [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	$ 76,679	$ 122,421

Fair Value Measurements - Summary of Changes in Fair Value of Company's Level 3 Assets and Liabilities (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Assets:
Beginning Balance	$ 1,508	$ 1,276	$ 1,315
Net Unrealized/Realized Gains/Losses Included In Earnings	14	248	14
Purchases/Acquisitions	1,661
Sales/ Dispositions/ Settlements	(1,669)
Foreign Currency Translation Adjustments	78	(16)	(53)
Ending Balance	1,592	1,508	1,276
Liabilities:
Beginning Balance	22,608
Net Unrealized/Realized Gains/Losses Included In Earnings	6,582	32,725
Purchases/Acquisitions	0	19,950
Sales/ Dispositions/ Settlements	(249)	(30,067)
Foreign Currency Translation Adjustments	0
Ending Balance	28,941	22,608
Contingent Consideration Liability [Member]
Liabilities:
Beginning Balance	22,608
Net Unrealized/Realized Gains/Losses Included In Earnings	6,582	32,725
Purchases/Acquisitions	0	19,950
Sales/ Dispositions/ Settlements	(249)	(30,067)
Foreign Currency Translation Adjustments	0
Ending Balance	28,941	22,608
Equities [Member]
Assets:
Beginning Balance	1,508	1,276	1,315
Net Unrealized/Realized Gains/Losses Included In Earnings	14	248	14
Purchases/Acquisitions	1,661
Sales/ Dispositions/ Settlements	(1,669)
Foreign Currency Translation Adjustments	78	(16)	(53)
Ending Balance	$ 1,592	$ 1,508	$ 1,276

Fair Value Measurements - Summary of Changes in Fair Value of Company's Level 3 Assets and Liabilities (Parenthetical) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Equities [Member]
Fair Value of Assets and Liabilities Measured on Recurring Basis Unobservable Input Reconciliation [Line Items]
Net unrealized gains	$ 12	$ 243	$ 14
Contingent Consideration Liability [Member]
Fair Value of Assets and Liabilities Measured on Recurring Basis Unobservable Input Reconciliation [Line Items]
Net unrealized losses	$ 6,582	2,658
Contingent Consideration Liability [Member] \| Edgewater Acquisition [Member]
Fair Value of Assets and Liabilities Measured on Recurring Basis Unobservable Input Reconciliation [Line Items]
Net realized losses		$ 30,067

Fair Value Measurements - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Fair Value Option Quantitative Disclosures [Line Items]
Transfers between Level 1, 2 and 3 in fair value measurement hierarchy	$ 0	$ 0
Unfunded Commitments	10,300,000	$ 9,183,000
EGCP III [Member]
Fair Value Option Quantitative Disclosures [Line Items]
Unfunded Commitments	$ 8,613,000
End of the investment period	Oct. 12, 2016
Remaining obligation date	Oct. 12, 2023

Fair Value Measurements - Financial Instruments Not Measured at Fair Value (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Financial Assets:
Cash and cash equivalents	$ 1,483,836	$ 1,158,785	$ 1,132,083	$ 1,066,580
Deposits with banks and short-term investments	935,431	419,668
Cash deposited with clearing organizations and other segregated cash	35,539	29,030
Interest-bearing financing receivables	80,536	76,133
Financial Liabilities:
Deposits and other customer payables	992,338	472,283
Senior debt	1,190,383	1,188,600
Carrying Value [Member]
Financial Assets:
Cash and cash equivalents	1,483,836	1,158,785
Deposits with banks and short-term investments	935,431	419,668
Cash deposited with clearing organizations and other segregated cash	35,539	29,030
Interest-bearing financing receivables	80,536	76,133
Interest-bearing deposits (included within investments)	556	456
Financial Liabilities:
Deposits and other customer payables	992,338	472,283
Senior debt	1,190,383	1,188,600
Fair Value [Member]
Financial Assets:
Deposits with banks and short-term investments	935,431	419,668
Cash deposited with clearing organizations and other segregated cash	35,539	29,030
Interest-bearing financing receivables	82,492	78,072
Cash and cash equivalents	1,483,836	1,158,785
Interest-bearing deposits (included within investments)	556	456
Financial Liabilities:
Deposits and other customer payables	992,338	472,283
Senior debt	1,230,254	1,204,171
Fair Value [Member] \| Level 1 [Member]
Financial Assets:
Deposits with banks and short-term investments	935,431	419,668
Cash deposited with clearing organizations and other segregated cash	35,539	29,030
Cash and cash equivalents	1,483,836	1,158,785
Interest-bearing deposits (included within investments)	556	456
Financial Liabilities:
Deposits and other customer payables	992,338	472,283
Fair Value [Member] \| Level 2 [Member]
Financial Liabilities:
Senior debt	1,230,254	1,204,171
Fair Value [Member] \| Level 3 [Member]
Financial Assets:
Interest-bearing financing receivables	$ 82,492	$ 78,072

Fair Value Measurements - Fair Value of Certain Investments Based on NAV (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Fair Value	$ 80,378	$ 129,591
Unfunded Commitments	10,300	9,183
Hedge Funds [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Fair Value	$ 2,517	$ 6,190
Hedge Funds [Member] \| Weekly [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Percent	3.00%	73.00%
Hedge Funds [Member] \| Monthly [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Percent	5.00%	2.00%
Hedge Funds [Member] \| Quarterly [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Percent	92.00%	25.00%
Hedge Funds [Member] \| Minimum [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Redemption Notice Period	30 days	30 days
Hedge Funds [Member] \| Maximum [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Redemption Notice Period	60 days	60 days
Funds of Funds [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Fair Value	$ 528	$ 492
Funds of Funds [Member] \| Monthly [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Percent	97.00%	98.00%
Funds of Funds [Member] \| Quarterly [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Percent	3.00%	2.00%
Funds of Funds [Member] \| Minimum [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Redemption Notice Period	30 days	30 days
Funds of Funds [Member] \| Maximum [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Redemption Notice Period	90 days	90 days
Other [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Fair Value	$ 595	$ 443
Other [Member] \| Monthly [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Percent	94.00%	93.00%
Other [Member] \| Daily [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Percent	6.00%	7.00%
Other [Member] \| Minimum [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Redemption Notice Period	30 days	30 days
Other [Member] \| Maximum [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Redemption Notice Period	60 days	60 days
Debt Funds [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Fair Value	$ 6	$ 6
Investments Redeemable, Redemption Notice Period	30 days	30 days
Debt Funds [Member] \| Daily [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Percent	100.00%	100.00%
Equity Funds [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Fair Value	$ 53	$ 39
Equity Funds [Member] \| Monthly [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Percent	50.00%	50.00%
Equity Funds [Member] \| Quarterly [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Percent	32.00%	31.00%
Equity Funds [Member] \| Daily [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Percent	18.00%	19.00%
Equity Funds [Member] \| Minimum [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Redemption Notice Period	30 days	30 days
Equity Funds [Member] \| Maximum [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Redemption Notice Period	90 days	90 days
Private Equity Funds [Member] \| Equity Growth [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Fair Value	$ 76,679	$ 90,824
Unfunded Commitments	$ 10,300	$ 9,183
% of Fair Value Not Redeemable	100.00%	100.00%
Estimated Liquidation Period of Investments Not Redeemable, % Next 5 Years	16.00%	12.00%
Estimated Liquidation Period of Investments Not Redeemable, % 5-10 Years	38.00%	33.00%
Estimated Liquidation Period of Investments Not Redeemable, % Thereafter	46.00%	55.00%
Private Equity Funds [Member] \| Mezzanine Debt [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Fair Value		$ 31,597
% of Fair Value Not Redeemable		100.00%
Estimated Liquidation Period of Investments Not Redeemable, % Thereafter		100.00%

Fair Value Measurements - Fair Value of Certain Investments Based on NAV (Parenthetical) (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Unfunded Commitments	$ 10,300	$ 9,183
Private Equity Funds [Member] \| Consolidated But Not Owned [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Unfunded Commitments	$ 5,902	$ 6,886

Derivatives - Fair Values of Derivatives Reported on Consolidated Statements of Financial Condition (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Derivative Assets	$ 3,732	$ 1,993
Derivative Liabilities	198,417	182,223
Forward Foreign Currency Exchange Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets	3,314	1,993
Derivative Liabilities	4,846	2,792
Total Return Swaps and Other [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets	418
Derivative Liabilities	11,270	9,043
LFI and Other Similar Deferred Compensation Arrangements [Member]
Derivatives, Fair Value [Line Items]
Derivative Liabilities	$ 182,301	$ 170,388

Derivatives - Fair Values of Derivatives Reported on Consolidated Statements of Financial Condition (Parenthetical) (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Gross derivative liability	$ 182,301	$ 170,388	$ 193,574
Total Return Swaps [Member]
Derivatives, Fair Value [Line Items]
Gross derivative assets	469	357
Gross derivative liability	11,321	9,400
Cash collateral pledged for total return swaps	$ 17,616	$ 16,996

Derivatives - Net Gains (Losses) with Respect to Derivative Instruments Not Designated as Hedging Instruments (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on derivatives instruments	$ (48,379)	$ (10,207)	$ 23,460
Forward Foreign Currency Exchange Rate Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on derivatives not designated as hedging instruments	(9,144)	(2,253)	15,773
LFI and Other Similar Deferred Compensation Arrangements [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on derivatives not designated as hedging instruments	(23,526)	(3,318)	3,827
Total Return Swaps and Other [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on derivatives designated as hedging instruments	$ (15,709)	$ (4,636)	$ 3,860

Property - Components of Property (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 523,128	$ 495,022
Less - Accumulated depreciation and amortization	317,827	286,001
Property	205,301	209,021
Buildings [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 151,912	132,821
Property, plant and equipment, useful life	33 years
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 173,102	175,810
Leasehold Improvements [Member] \| Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	3 years
Leasehold Improvements [Member] \| Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	20 years
Furniture and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 183,541	172,353
Furniture and Equipment [Member] \| Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	3 years
Furniture and Equipment [Member] \| Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	10 years
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 14,573	$ 14,038

Goodwill and Other Intangible Assets - Components of Goodwill and Other Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill	$ 385,292	$ 373,117	$ 320,761	$ 335,402
Other intangible assets (net of accumulated amortization)	6,072	8,907
Goodwill and other intangible assets, Total	$ 391,364	$ 382,024

Goodwill and Other Intangible Assets - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Goodwill And Intangible Assets [Line Items]
Goodwill	$ 385,292,000	$ 373,117,000	$ 320,761,000	$ 335,402,000
Goodwill impairment loss	0	0	0
Amortization of intangible assets	2,932,000	2,522,000	$ 5,821,000
Financial Advisory Segment [Member]
Goodwill And Intangible Assets [Line Items]
Goodwill	320,751,000	308,576,000
Asset Management Segment [Member]
Goodwill And Intangible Assets [Line Items]
Goodwill	$ 64,541,000	$ 64,541,000

Goodwill and Other Intangible Assets - Changes in Carrying Amount of Goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill And Intangible Assets Disclosure [Abstract]
Beginning Balance	$ 373,117	$ 320,761	$ 335,402
Business acquisitions		54,631
Foreign currency translation adjustments	12,175	(2,275)	(14,641)
Ending Balance	$ 385,292	$ 373,117	$ 320,761

Goodwill and Other Intangible Assets - Gross Cost and Accumulated Amortization of Other Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Other intangible assets, Gross Cost	$ 69,171	$ 68,987
Other intangible assets, accumulated amortization	63,099	60,080
Other intangible assets, Net Carrying Amount	6,072	8,907
Success/Incentive Fees [Member]
Finite-Lived Intangible Assets [Line Items]
Other intangible assets, Gross Cost	35,422	35,259
Other intangible assets, accumulated amortization	29,723	26,984
Other intangible assets, Net Carrying Amount	5,699	8,275
Management Fees, Customer Relationships and Non-Compete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Other intangible assets, Gross Cost	33,749	33,728
Other intangible assets, accumulated amortization	33,376	33,096
Other intangible assets, Net Carrying Amount	$ 373	$ 632

Goodwill and Other Intangible Assets - Estimated Future Amortization Expense (Detail) $ in Thousands	Dec. 31, 2017 USD ($)
Goodwill And Intangible Assets Disclosure [Abstract]
2018	$ 2,941
2019	1,577
2020	1,554
Total amortization expense	$ 6,072

Goodwill and Other Intangible Assets - Estimated Future Amortization Expense (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Percentage of intangible asset amortization attributable to non-controlling interests	35.00%

Other Assets and Other Liabilities - Schedule of Other Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Current tax receivables and other taxes	$ 38,804	$ 31,767
Prepaid compensation (see Note 14)	60,355	49,650	$ 75,703
Other advances and prepayments	56,595	35,706
Other	72,390	67,376
Total	$ 228,144	$ 184,499

Other Assets and Other Liabilities - Schedule of Other Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Other Liabilities Disclosure [Abstract]
Accrued expenses	$ 155,551	$ 124,721
Current income taxes and other taxes	123,548	99,278
Employee benefit-related liabilities	69,201	84,703
Deferred lease incentives	85,028	84,287
Unclaimed funds at LFB	14,962	24,997
Deferred revenue	45,390	35,717
Contingent consideration liability	28,941	22,608
Securities sold, not yet purchased	7,338	4,482
Other	43,629	56,653
Total	$ 573,588	$ 537,446

Senior Debt - Senior Debt (Detail) - USD ($)	12 Months Ended
Senior Debt - Senior Debt (Detail) - USD ($)	Dec. 31, 2017	Dec. 31, 2016	Nov. 30, 2016	Feb. 28, 2015
Debt Instrument [Line Items]
Senior Debt, Outstanding Principal	$ 1,200,000,000	$ 1,200,000,000
Senior Debt, Outstanding Unamortized Debt Costs	9,617,000	11,400,000
Senior Debt, Outstanding Carrying Value	1,190,383,000	1,188,600,000
Lazard Group 4.25% Senior Notes [Member]
Debt Instrument [Line Items]
Senior Debt, Initial Principal Amount	$ 500,000,000
Senior Debt, Maturity Date	Nov. 14, 2020
Senior Debt, Annual Interest Rate	4.25%
Senior Debt, Outstanding Principal	$ 500,000,000	500,000,000
Senior Debt, Outstanding Unamortized Debt Costs	2,647,000	3,569,000
Senior Debt, Outstanding Carrying Value	497,353,000	496,431,000
Lazard Group 3.75% Senior Notes [Member]
Debt Instrument [Line Items]
Senior Debt, Initial Principal Amount	$ 400,000,000			$ 400,000,000
Senior Debt, Maturity Date	Feb. 13, 2025
Senior Debt, Annual Interest Rate	3.75%			3.75%
Senior Debt, Outstanding Principal	$ 400,000,000	400,000,000
Senior Debt, Outstanding Unamortized Debt Costs	3,361,000	3,833,000
Senior Debt, Outstanding Carrying Value	396,639,000	396,167,000
Lazard Group 3.625% Senior Notes [Member]
Debt Instrument [Line Items]
Senior Debt, Initial Principal Amount	$ 300,000,000		$ 300,000,000
Senior Debt, Maturity Date	Mar. 01, 2027
Senior Debt, Annual Interest Rate	3.625%		3.625%
Senior Debt, Outstanding Principal	$ 300,000,000	300,000,000
Senior Debt, Outstanding Unamortized Debt Costs	3,609,000	3,998,000
Senior Debt, Outstanding Carrying Value	$ 296,391,000	$ 296,002,000

Senior Debt - Senior Debt (Parenthetical) (Detail) - USD ($)	1 Months Ended		12 Months Ended
	Nov. 30, 2016	Feb. 28, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Loss on extinguishment of debt				$ 3,148,000	$ 60,219,000
Lazard Group 3.625% Senior Notes [Member]
Debt Instrument [Line Items]
Senior Debt, Initial Principal Amount	$ 300,000,000		$ 300,000,000
Senior notes interest rate	3.625%		3.625%
Original Maturity Date			Mar. 01, 2027
Interest rate, payment terms			Interest on the 2027 Notes is payable semi-annually on March 1 and September 1 of each year, beginning March 1, 2017.
Effective interest rates of senior notes			3.76%
Lazard Group 6.85% Senior Notes [Member]
Debt Instrument [Line Items]
Senior notes interest rate	6.85%
Redemption of senior debt	$ 98,350,000	$ 450,000,000
Original Maturity Date	Jun. 15, 2017
Loss on extinguishment of debt				$ 3,148,000	$ 60,219,000
Lazard Group 3.75% Senior Notes [Member]
Debt Instrument [Line Items]
Senior Debt, Initial Principal Amount		$ 400,000,000	$ 400,000,000
Senior notes interest rate		3.75%	3.75%
Original Maturity Date			Feb. 13, 2025
Interest rate, payment terms			Interest on the 2025 Notes is payable semi-annually on March 1 and September 1 of each year.
Effective interest rates of senior notes			3.87%
Lazard Group 4.25% Senior Notes [Member]
Debt Instrument [Line Items]
Senior Debt, Initial Principal Amount			$ 500,000,000
Senior notes interest rate			4.25%
Original Maturity Date			Nov. 14, 2020
Effective interest rates of senior notes			4.43%

Senior Debt - Additional Information (Detail) - USD ($)	Sep. 25, 2015	Dec. 31, 2017	Dec. 31, 2016
Unused Lines of Credit [Member]
Debt Instrument [Line Items]
Unused lines of credit		$ 169,000,000
LFB [Member] \| Unused Lines of Credit [Member]
Debt Instrument [Line Items]
Unused lines of credit		18,000,000
Amended and Restated Credit Agreement [Member]
Debt Instrument [Line Items]
Senior revolving credit facility	$ 150,000,000
Duration of senior revolving credit facility, in years	5 years
Expiration of credit facility	2020-09
Outstanding credit facility		$ 0	$ 0

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References + Details

Senior Debt - Debt Maturities Relating to Senior Borrowings Outstanding (Detail) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Total	$ 1,200,000,000	$ 1,200,000,000
Senior Borrowings Outstanding [Member]
Debt Instrument [Line Items]
2018 - 2019	0
2020	500,000,000
2021 - 2022	0
Thereafter	700,000,000
Total	$ 1,200,000,000

Commitments and Contingencies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Other Commitments [Line Items]
Office space and equipment under non-cancelable lease agreements, expiration through year	2033
Rental expense relating to operating leases	$ 84,632,000	$ 76,704,000	$ 79,549,000
Office space under sublease agreements, expiration through year	2022
Sublease income	$ 7,659,000	7,858,000	9,587,000
Capital lease obligation paid through	2017
Book value of assets under capital lease		$ 13,628,000
Guarantees indemnifications	$ 2,995,000
Collateral/counter-guarantees	2,995,000
LFB [Member]
Other Commitments [Line Items]
Other commitments	0
LFNY [Member]
Other Commitments [Line Items]
Other commitments	$ 0
Business Acquisitions [Member]
Other Commitments [Line Items]
Number of contingent additional shares earned	0
Business Acquisitions [Member] \| Class A Common Stock [Member]
Other Commitments [Line Items]
Common stock issued and issuable		60,817
Contingent shares issuable upon satisfaction of performance thresholds		810,742
Business Acquisitions [Member] \| Class A Common Stock [Member] \| Non-Contingent [Member]
Other Commitments [Line Items]
Common stock issued and issuable		204,651
Buildings [Member]
Other Commitments [Line Items]
Net book value of certain buildings that primarily collateralized capital lease obligations		$ 13,538,000
LMDC Holdings [Member]
Other Commitments [Line Items]
Sublease income			$ 1,281,000

Commitments and Contingencies - Schedule of Future Minimum Rental Payment for Operating Leases (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)
Commitments And Contingencies Disclosure [Abstract]
Minimum Rental Commitments Operating - 2018	$ 83,851
Minimum Rental Commitments Operating - 2019	73,889
Minimum Rental Commitments Operating - 2020	69,845
Minimum Rental Commitments Operating - 2021	67,118
Minimum Rental Commitments Operating - 2022	56,268
Minimum Rental Commitments Operating - Thereafter	442,438
Total minimum lease payments - Operating	793,409
Less sublease proceeds	36,141
Net lease payments	$ 757,268

Stockholders' Equity - Schedule of Share Repurchase Authorized by Board of Directors (Detail)	12 Months Ended
	Dec. 31, 2017 USD ($)
April, 2014 [Member]
Equity, Class of Treasury Stock [Line Items]
Share Repurchase Authorization	$ 200,000,000
Expiration	Dec. 31, 2015
February, 2015 [Member]
Equity, Class of Treasury Stock [Line Items]
Share Repurchase Authorization	$ 150,000,000
Expiration	Dec. 31, 2016
January, 2016 [Member]
Equity, Class of Treasury Stock [Line Items]
Share Repurchase Authorization	$ 200,000,000
Expiration	Dec. 31, 2017
April, 2016 [Member]
Equity, Class of Treasury Stock [Line Items]
Share Repurchase Authorization	$ 113,182,000
Expiration	Dec. 31, 2017
November, 2016 [Member]
Equity, Class of Treasury Stock [Line Items]
Share Repurchase Authorization	$ 236,000,000
Expiration	Dec. 31, 2018
October, 2017 [Member]
Equity, Class of Treasury Stock [Line Items]
Share Repurchase Authorization	$ 200,000,000
Expiration	Dec. 31, 2019

Stockholders' Equity - Schedule of Shares Repurchased Under the Share Repurchase Program (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share Repurchase Program [Abstract]
Purchase of Class A common stock (in shares)	6,956,097	8,551,271	3,438,789
Average Price Per Share	$ 44.10	$ 35.11	$ 50.24

Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended								12 Months Ended
	Jan. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule Of Stockholders Equity [Line Items]
Common stock held by subsidiaries, shares		10,747,142				7,628,786				10,747,142	7,628,786
Shares repurchased, value										$ 306,741	$ 300,217	$ 172,772
Share repurchase remaining authorization		$ 248,384								$ 248,384
Preferred stock, shares authorized		15,000,000				15,000,000				15,000,000	15,000,000
Preferred stock, par value		$ 0.01				$ 0.01				$ 0.01	$ 0.01
Conversion of Series A preferred stock into Class A common stock												0
Dividend declared per share of common stock		$ 0.41	$ 0.41	$ 0.41	$ 1.58	$ 0.38	$ 0.38	$ 0.38	$ 1.55	$ 2.81	$ 2.69	$ 2.35
Subsequent Event [Member]
Schedule Of Stockholders Equity [Line Items]
Dividend declared per share of common stock	$ 1.71
Dividend payable date	Feb. 23, 2018
Dividend date of record	Feb. 12, 2018
Dividend declare date	Jan. 31, 2018
Subsequent Event [Member] \| Quarterly Dividend [Member]
Schedule Of Stockholders Equity [Line Items]
Dividend declared per share of common stock	$ 0.41
Subsequent Event [Member] \| Extra Cash Dividend [Member]
Schedule Of Stockholders Equity [Line Items]
Dividend declared per share of common stock	$ 1.30
November, 2016 [Member]
Schedule Of Stockholders Equity [Line Items]
Share repurchase remaining authorization		$ 48,384								$ 48,384
Share repurchase authorization expiration date										Dec. 31, 2018
October, 2017 [Member]
Schedule Of Stockholders Equity [Line Items]
Share repurchase remaining authorization		$ 200,000								$ 200,000
Share repurchase authorization expiration date										Dec. 31, 2019
Class A Common Stock [Member]
Schedule Of Stockholders Equity [Line Items]
Common stock held by subsidiaries, shares		10,747,142				7,628,786				10,747,142	7,628,786
Class A Common Stock [Member] \| Executive Officers [Member]
Schedule Of Stockholders Equity [Line Items]
Shares repurchased, value										$ 14,700	$ 4,900	$ 17,700
Series A Preferred Stock [Member]
Schedule Of Stockholders Equity [Line Items]
Preferred stock, shares outstanding		0				0				0	0	7,921
Series B Preferred Stock [Member]
Schedule Of Stockholders Equity [Line Items]
Preferred stock, shares outstanding		0				0				0	0	0

Stockholders' Equity - Accumulated Other Comprehensive Income (Loss), Net of Tax (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	$ 1,293,813	$ 1,367,306	$ 770,057
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX	81,705	(79,867)	(33,590)
Balance	1,258,905	1,293,813	1,367,306
Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(155,204)	(97,284)	(46,102)
Other comprehensive income (loss) before reclassifications	71,669	(57,920)	(51,182)
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX	71,669	(57,920)	(51,182)
Balance	(83,535)	(155,204)	(97,284)
Employee Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(159,020)	(137,073)	(154,665)
Other comprehensive income (loss) before reclassifications	2,085	(24,473)	11,283
Adjustments for items reclassified to earnings, net of tax	7,951	2,526	6,309
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX	10,036	(21,947)	17,592
Balance	(148,984)	(159,020)	(137,073)
Total AOCI [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(314,224)	(234,357)	(200,767)
Other comprehensive income (loss) before reclassifications	73,754	(82,393)	(39,899)
Adjustments for items reclassified to earnings, net of tax	7,951	2,526	6,309
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX	81,705	(79,867)	(33,590)
Balance	(232,519)	(314,224)	(234,357)
AOCI Attributable to Noncontrolling Interest [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(2)	(1)	(1)
Other comprehensive income (loss) before reclassifications	1	(1)
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX	1	(1)
Balance	(1)	(2)	(1)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(314,222)	(234,356)	(200,766)
Other comprehensive income (loss) before reclassifications	73,753	(82,392)	(39,899)
Adjustments for items reclassified to earnings, net of tax	7,951	2,526	6,309
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX	81,704	(79,866)	(33,590)
Balance	$ (232,518)	$ (314,222)	$ (234,356)

Stockholders' Equity - Adjustments for Items Reclassified Out of AOCI (Detail) - Accumulated Defined Benefit Plans Adjustment [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Amortization relating to employee benefit plans	$ 10,171	$ 4,283	$ 7,816
Less - related income taxes	2,220	1,757	1,507
Total reclassifications, net of tax	$ 7,951	$ 2,526	$ 6,309

Stockholders' Equity - Net Income Attributable to Noncontrolling Interests (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Change In Ownership Interest [Line Items]
Net Income Attributable to Noncontrolling Interests	$ 604	$ 2,260	$ 523	$ 2,877	$ 1,005	$ 82	$ 1,007	$ 3,900	$ 6,264	$ 5,994	$ 6,559
Noncontrolling interests	59,102				57,826				59,102	57,826
Edgewater [Member]
Change In Ownership Interest [Line Items]
Net Income Attributable to Noncontrolling Interests									6,259	5,992	6,557
Noncontrolling interests	58,568				57,238				58,568	57,238
Other [Member]
Change In Ownership Interest [Line Items]
Net Income Attributable to Noncontrolling Interests									5	2	$ 2
Noncontrolling interests	$ 534				$ 588				$ 534	$ 588

Incentive Plans - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Feb. 26, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Subsequent Event [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense, years	2 years 8 months 12 days
Deferred incentive compensation awards including PRSUs valued at target payout level	$ 351,000
Lazard Fund Interests [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense, years		10 months 24 days
Lazard Fund Interests [Member] \| Subsequent Event [Member] \| One-Third Vesting [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incentive awards, vesting date	Mar. 02, 2020
Lazard Fund Interests [Member] \| Subsequent Event [Member] \| Two-Thirds Vesting [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incentive awards, vesting date	Mar. 01, 2021
Non-Executive [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of annual compensation received by directors in the form of DSUs		55.00%
RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock conversion basis		one-for-one
Grant date fair value, amortized periods		generally one-third after two years, and the remaining two-thirds after the third year
Unrecognized compensation expense		$ 139,793
Unrecognized compensation expense, years		9 months 18 days
RSUs [Member] \| Subsequent Event [Member] \| One-Third Vesting [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incentive awards, vesting date	Mar. 02, 2020
RSUs [Member] \| Subsequent Event [Member] \| Two-Thirds Vesting [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incentive awards, vesting date	Mar. 01, 2021
DSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual compensation paid in DSUs		31,280	38,771	23,961
Units granted under the directors deferred unit plan		13,882	10,043	2,482
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense		$ 27,181
Unrecognized compensation expense, years		9 months 18 days
PRSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense		$ 9,174
Unrecognized compensation expense, years		8 months 12 days
Percentage of target number of shares subject to each PRSU no longer subject to forfeiture due to threshold level of performance being achieved		25.00%
Descriptions of vesting period associated with PRSUs		PRSUs will vest on a single date approximately three years following the date of the grant
Vesting period of PRSUs granted		3 years
PSRU's target share distribution for Class A common stock, description		The target number of shares of Class A common stock subject to each PRSU is one; however, based on the achievement of the performance criteria, the number of shares of Class A common stock that may be received in connection with each PRSU generally can range from zero to two times the target number.
PRSUs [Member] \| Subsequent Event [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incentive awards, vesting date	Mar. 01, 2021
Class A Common Stock [Member] \| RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Withholding taxes in lieu of share delivery		1,290,601	1,421,396	2,249,935
Delivery of common stock associated with stock awards		2,707,562	3,118,998	5,506,133
Class A Common Stock [Member] \| Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Withholding taxes in lieu of share delivery		150,470	141,026	108,833
Delivery of common stock associated with stock awards		341,206	678,846	438,291
Class A Common Stock [Member] \| Restricted Stock [Member] \| Subsequent Event [Member] \| One-Third Vesting [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incentive awards, vesting date	Mar. 02, 2020
Class A Common Stock [Member] \| Restricted Stock [Member] \| Subsequent Event [Member] \| Two-Thirds Vesting [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incentive awards, vesting date	Mar. 01, 2021
Class A Common Stock [Member] \| PRSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Withholding taxes in lieu of share delivery		127,530	64,169	32,086
Delivery of common stock associated with stock awards		698,035	352,852	664,413
Class A Common Stock [Member] \| Awarded Under 2008 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of outstanding class A common stock that can be awarded under plan		30.00%
Compensation plan expiration period		May 31, 2018
Class A Common Stock [Member] \| 2005 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized pertaining to share based compensation arrangements, 2005 Plan		25,000,000

Incentive Plans - Summary of Impact of Share-Based Incentive Plans on Compensation and Benefits Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based incentive awards:
Share-based incentive awards	$ 272,965	$ 261,462	$ 226,723
RSUs [Member]
Share-based incentive awards:
Share-based incentive awards	190,821	171,188	166,395
PRSUs [Member]
Share-based incentive awards:
Share-based incentive awards	40,767	43,018	36,529
Restricted Stock [Member]
Share-based incentive awards:
Share-based incentive awards	39,369	45,536	22,342
DSUs [Member]
Share-based incentive awards:
Share-based incentive awards	$ 2,008	$ 1,720	$ 1,457

Incentive Plans - Schedule of Issuance of RSUs and Charges to Retained Earnings (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of RSUs issued	985,584	1,085,354	693,714
Charges to retained earnings, net of estimated forfeitures	$ 41,746	$ 37,284	$ 34,255

Incentive Plans - Schedule of Activity Relating to RSUs and DSUs (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
RSUs [Member]
Share-based compensation arrangement by share-based payment award [Line Items]
Units, Beginning Balance	11,698,138	9,599,658	13,529,116
Units, Granted	5,437,591	6,878,306	4,296,386
Units, Forfeited	(217,720)	(239,432)	(469,776)
Units, Vested	(3,998,163)	(4,540,394)	(7,756,068)
Units, Ending Balance	12,919,846	11,698,138	9,599,658
Weighted Average Grant Date Fair Value, Beginning Balance	$ 40.65	$ 44.06	$ 35.19
Weighted Average Grant Date Fair Value, Granted	43.03	34.86	48.57
Weighted Average Grant Date Fair Value, Forfeited	40.20	39.53	43.54
Weighted Average Grant Date Fair Value, Vested	45.26	39.16	31.12
Weighted Average Grant Date Fair Value, Ending Balance	$ 40.23	$ 40.65	$ 44.06
DSUs [Member]
Share-based compensation arrangement by share-based payment award [Line Items]
Units, Beginning Balance	276,725	312,670	286,227
Units, Granted	45,162	48,814	26,443
Units, Vested	(43,465)	(84,759)
Units, Ending Balance	278,422	276,725	312,670
Weighted Average Grant Date Fair Value, Beginning Balance	$ 36.05	$ 35.98	$ 34.21
Weighted Average Grant Date Fair Value, Granted	44.46	35.23	55.11
Weighted Average Grant Date Fair Value, Vested	35.77	35.30
Weighted Average Grant Date Fair Value, Ending Balance	$ 37.46	$ 36.05	$ 35.98

Incentive Plans - Schedule of Activity Relating to RSUs and DSUs (Parenthetical) (Detail) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Dividend participation rights	985,584	1,085,354	693,714

Incentive Plans - Summary of Activity Related to Shares of Restricted Class A Common Stock (Detail) - Restricted Stock [Member] - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based compensation arrangement by share-based payment award [Line Items]
Units, Beginning Balance	1,655,073	713,738	729,827
Units, Granted	841,355	1,795,258	576,886
Units, Forfeited	(66,592)	(34,051)	(45,851)
Units, Vested	(491,676)	(819,872)	(547,124)
Units, Ending Balance	1,938,160	1,655,073	713,738
Weighted Average Grant Date Fair Value, Beginning Balance	$ 40.95	$ 47.12	$ 38.63
Weighted Average Grant Date Fair Value, Granted	42.58	36.76	50.88
Weighted Average Grant Date Fair Value, Forfeited	40.80	40.48	50.17
Weighted Average Grant Date Fair Value, Vested	45.35	37.16	39.50
Weighted Average Grant Date Fair Value, Ending Balance	$ 40.54	$ 40.95	$ 47.12

Incentive Plans - Summary of Activity Relating to PRSUs (Detail) - PRSUs [Member] - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based compensation arrangement by share-based payment award [Line Items]
Units, Beginning Balance	1,590,756	1,019,038	1,347,148
Units, Granted	458,113	627,956	368,389
Units, Earned	368,389	360,783
Units, Vested	(825,565)	(417,021)	(696,499)
Units, Ending Balance	1,591,693	1,590,756	1,019,038
Weighted Average Grant Date Fair Value, Beginning Balance	$ 40.76	$ 44.49	$ 37.79
Weighted Average Grant Date Fair Value, Granted	43.76	32.91	52.85
Weighted Average Grant Date Fair Value, Earned	47.74	41.20
Weighted Average Grant Date Fair Value, Vested	42.27	38.43	35.96
Weighted Average Grant Date Fair Value, Ending Balance	$ 42.46	$ 40.76	$ 44.49

Incentive Plans - Summary of LFI and Other Similar Deferred Compensation Arrangements (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Deferred Compensation Arrangements [Abstract]
Prepaid Compensation Asset, Beginning Balance	$ 49,650	$ 75,703
Prepaid Compensation Asset, Granted	77,580	52,121
Prepaid Compensation Asset, Forfeited	(992)	(2,942)
Prepaid Compensation Asset, Amortization	(67,575)	(73,340)
Prepaid Compensation Asset, Other	1,692	(1,892)
Prepaid Compensation Asset, Ending Balance	60,355	49,650
Compensation Liability, Beginning Balance	170,388	193,574
Compensation Liability, Granted	77,580	52,121
Compensation Liability, Settled	(96,025)	(77,457)
Compensation Liability, Forfeited	(1,819)	(5,380)
Compensation Liability, Increase (Decrease) in fair value of underlying investments	23,526	3,318
Compensation Liability, Adjustment for estimated forfeitures	6,634	4,671
Compensation Liability, Other	2,017	(459)
Compensation Liability, Ending Balance	$ 182,301	$ 170,388

Incentive Plans - Summary of Impact of LFI and Other Similar Deferred Compensation Arrangements (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share Based Compensation [Abstract]
Amortization, net of forfeitures	$ 73,382	$ 75,573	$ 85,563
Change in the fair value of underlying investments	23,526	3,318	(3,827)
Total	$ 96,908	$ 78,891	$ 81,736

Employee Benefit Plans - Additional Information (Detail) - USD ($)	1 Months Ended	12 Months Ended
	Oct. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Equity funds managed by LAM		$ 102,455,000	$ 97,933,000
Contributions to employer sponsored defined contribution plans		15,065,000	$ 14,454,000	$ 12,493,000
Non-U.S. Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected contribution related to the pension plans		$ 21,000,000
U.S. Pension Plans [Member] \| Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of plans' assets in debt funds		45.00%	47.00%
U.S. Pension Plans [Member] \| Level 1 [Member] \| NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of plans' assets in equity funds		55.00%	53.00%
Non-U.S. Pension Plans [Member] \| Level 1 [Member] \| Equities And Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of plan assets invested		32.00%	31.00%
Non-U.S. Pension Plans [Member] \| Level 1 [Member] \| NAV [Member] \| Debt and Debt Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of plan assets invested		62.00%	62.00%
Non-U.S. Pension Plans [Member] \| Level 1 [Member] \| NAV [Member] \| Cash And Alternative Investment Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of plan assets invested		6.00%	7.00%
Scenario Forecast [Member] \| U.S. Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected contribution related to the pension plans					$ 0
Medical Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Settlement of defined benefit plan	$ 2,936,000
Gain on settlement of defined benefit plan			$ 1,788,000

Employee Benefit Plans - Summary of Changes in Benefit Obligations, Fair Value of Assets, Funded Status and Amounts Recognized in Consolidated Statements of Financial Condition (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Change in benefit obligation
Benefit obligation at beginning of year	$ 718,821
Benefit obligation at end of year	763,831	$ 718,821
Change in plan assets
Fair value of plan assets at beginning of year	646,119
Fair value of plan assets at end of year	728,281	646,119
Pension Plans [Member]
Change in benefit obligation
Benefit obligation at beginning of year	718,821	694,187
Service cost	1,413	1,235	$ 1,530
Interest cost	16,240	19,871	24,600
Actuarial (gain) loss	2,702	135,164
Benefits paid	(44,589)	(31,904)
Foreign currency translation and other adjustments	69,244	(99,732)
Benefit obligation at end of year	763,831	718,821	694,187
Change in plan assets
Fair value of plan assets at beginning of year	646,119	656,084
Actual return on plan assets	43,624	119,287	9,873
Employer contributions	16,844	11,343	39,301
Benefits paid	(42,022)	(29,384)	(32,321)
Foreign currency translation and other adjustments	63,716	(111,211)
Fair value of plan assets at end of year	728,281	646,119	656,084
Funded (deficit) at end of year	(35,550)	(72,702)
Prepaid pension asset (included in “other assets”)	16,189	822
Accrued benefit liability (included in “other liabilities”)	(51,739)	(73,524)
Net amount recognized	(35,550)	(72,702)
Actuarial net loss (gain)	184,135	192,855
Prior service cost		30
Net amount recognized	$ 184,135	192,885
Medical Plan [Member]
Change in benefit obligation
Benefit obligation at beginning of year		4,750
Service cost		11	27
Interest cost		167	179
Actuarial (gain) loss		(1,639)
Benefits paid		(3,289)
Benefit obligation at end of year			4,750
Change in plan assets
Employer contributions		3,289	276
Benefits paid		$ (3,289)	$ (276)

Employee Benefit Plans - Summary of Changes in Benefit Obligations, Fair Value of Assets, Funded Status and Amounts Recognized in Consolidated Statements of Financial Condition (Parenthetical) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Pension Plans And Defined Benefit Postretirement Plans Disclosure [Abstract]
Excluding tax benefits on amounts recognized	$ 35,154	$ 33,864

Employee Benefit Plans - Summary of Fair Value of Plan Assets, Accumulated Benefit Obligation and Projected Benefit Obligation (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 728,281	$ 646,119
Accumulated benefit obligation	763,831	718,821
Projected benefit obligation	763,831	718,821
U.S. Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	24,644	22,161
Accumulated benefit obligation	35,376	33,868
Projected benefit obligation	35,376	33,868
Non-U.S. Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	703,637	623,958
Accumulated benefit obligation	728,455	684,953
Projected benefit obligation	$ 728,455	$ 684,953

Employee Benefit Plans - Components of Net Periodic Benefit Cost (Credit) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Pension Plans [Member]
Components of Net Periodic Benefit Cost (Credit):
Service cost	$ 1,413	$ 1,235	$ 1,530
Interest cost	16,240	19,871	24,600
Expected return on plan assets	(25,300)	(27,337)	(28,301)
Amortization of:
Prior service cost	30	2,369	2,376
Net actuarial loss (gain)	10,141	3,888	5,440
Settlement loss (gain)	807
Net periodic benefit cost (credit)	3,331	26	5,645
Actual return on plan assets	43,624	119,287	9,873
Employer contributions	16,844	11,343	39,301
Benefits paid	42,022	29,384	32,321
Net actuarial (gain) loss	(17,357)	51,626	(4,650)
Reclassification of prior service (cost) credit to earnings	(30)	(2,369)	(2,376)
Reclassification of actuarial gain (loss) to earnings	(10,141)	(3,888)	(5,440)
Currency translation and other adjustments	18,778	(20,309)	(11,582)
Total recognized in AOCI	(8,750)	25,060	(24,048)
Net amount recognized in total periodic benefit cost and AOCI	$ (5,419)	25,086	(18,403)
Medical Plan [Member]
Components of Net Periodic Benefit Cost (Credit):
Service cost		11	27
Interest cost		167	179
Amortization of:
Net actuarial loss (gain)		(185)
Settlement loss (gain)		(1,788)
Net periodic benefit cost (credit)		(1,795)	206
Employer contributions		3,289	276
Benefits paid		3,289	276
Net actuarial (gain) loss		(1,638)	(695)
Reclassification of actuarial gain (loss) to earnings		1,973
Total recognized in AOCI		335	(695)
Net amount recognized in total periodic benefit cost and AOCI		$ (1,460)	$ (489)

Employee Benefit Plans - Components of Net Periodic Benefit Cost (Credit) (Parenthetical) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Pension Plans And Defined Benefit Postretirement Plans Disclosure [Abstract]
Tax expense (benefit) on other changes in plan assets and benefit obligations recognized in AOCI	$ (1,287)	$ (3,448)	$ 7,151

Employee Benefit Plans - Schedule of Amounts in AOCI on Consolidated Statement of Financial Condition Expected to be Recognized (Detail) $ in Thousands	Dec. 31, 2017 USD ($)
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	$ 5,072

Employee Benefit Plans - Schedule of Assumptions Used to Develop Actuarial Present Value of Projected Benefit Obligation and Net Periodic Pension Cost (Detail)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average assumptions used to determine benefit obligations, Discount rate	2.30%	2.50%	3.50%
Weighted average assumptions used to determine net periodic benefit cost, Discount rate	2.20%	1.90%	2.60%
Weighted average assumptions used to determine net periodic benefit cost, Expected long-term rate of return on plan assets	3.80%	4.60%	4.30%
Medical Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average assumptions used to determine benefit obligations, Discount rate			3.90%
Weighted average assumptions used to determine net periodic benefit cost, Discount rate		3.90%	3.70%
Healthcare cost trend rates used to determine net periodic benefit cost, Initial		6.50%	7.00%
Healthcare cost trend rates used to determine net periodic benefit cost, Ultimate		5.00%	5.00%
Healthcare cost trend rates used to determine net periodic benefit cost, Year ultimate trend rate achieved		2019	2019

Employee Benefit Plans - Schedule of Expected Benefit Payments (Detail) - Pension Plans [Member] $ in Thousands	Dec. 31, 2017 USD ($)
Defined Benefit Plan Disclosure [Line Items]
2018	$ 24,631
2019	25,347
2020	25,351
2021	26,981
2022	29,287
2023-2027	$ 153,490

Employee Benefit Plans - Schedule of Categorization of Plans' Assets (Detail) - USD ($)
$ in Thousands

Dec. 31, 2017

Dec. 31, 2016

Defined Benefit Plan Disclosure [Line Items]

Plan assets measured at fair value

$ 728,281

$ 646,119

Derivative [Member]

Defined Benefit Plan Disclosure [Line Items]

Plan assets measured at fair value

664

618

NAV [Member]

Defined Benefit Plan Disclosure [Line Items]

Plan assets measured at fair value

^[1]

397,868

349,751

Level 1 [Member]

Defined Benefit Plan Disclosure [Line Items]

Plan assets measured at fair value

326,003

295,750

Level 2 [Member]

Defined Benefit Plan Disclosure [Line Items]

Plan assets measured at fair value

4,410

618

Level 2 [Member] | Derivative [Member]

Defined Benefit Plan Disclosure [Line Items]

Plan assets measured at fair value

664

618

Cash [Member]

Defined Benefit Plan Disclosure [Line Items]

Plan assets measured at fair value

11,544

23,341

Cash [Member] | Level 1 [Member]

Defined Benefit Plan Disclosure [Line Items]

Plan assets measured at fair value

11,544

23,341

Debt [Member]

Defined Benefit Plan Disclosure [Line Items]

Plan assets measured at fair value

73,728

63,431

Debt [Member] | Level 1 [Member]

Defined Benefit Plan Disclosure [Line Items]

Plan assets measured at fair value

73,728

63,431

Equities [Member]

Defined Benefit Plan Disclosure [Line Items]

Plan assets measured at fair value

36,854

29,287

Equities [Member] | Level 1 [Member]

Defined Benefit Plan Disclosure [Line Items]

Plan assets measured at fair value

36,854

29,287

Alternative Investment Funds [Member]

Defined Benefit Plan Disclosure [Line Items]

Plan assets measured at fair value

25,938

24,278

Alternative Investment Funds [Member] | NAV [Member]

Defined Benefit Plan Disclosure [Line Items]

Plan assets measured at fair value

^[1]

25,938

23,062

Alternative Investment Funds [Member] | Level 1 [Member]

Defined Benefit Plan Disclosure [Line Items]

Plan assets measured at fair value

1,216

Debt Funds [Member]

Defined Benefit Plan Disclosure [Line Items]

Plan assets measured at fair value

374,917

331,054

Debt Funds [Member] | NAV [Member]

Defined Benefit Plan Disclosure [Line Items]

Plan assets measured at fair value

^[1]

363,915

320,560

Debt Funds [Member] | Level 1 [Member]

Defined Benefit Plan Disclosure [Line Items]

Plan assets measured at fair value

11,002

10,494

Equity Funds [Member]

Defined Benefit Plan Disclosure [Line Items]

Plan assets measured at fair value

204,636

174,110

Equity Funds [Member] | NAV [Member]

Defined Benefit Plan Disclosure [Line Items]

Plan assets measured at fair value

^[1]

8,015

6,129

Equity Funds [Member] | Level 1 [Member]

Defined Benefit Plan Disclosure [Line Items]

Plan assets measured at fair value

192,875

$ 167,981

Equity Funds [Member] | Level 2 [Member]

Defined Benefit Plan Disclosure [Line Items]

Plan assets measured at fair value

$ 3,746

[1]	Represents certain investments measured at NAV or its equivalent as a practical expedient in determining fair value. In accordance with current accounting guidance, these investments have not been classified in the fair value hierarchy.

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jan. 01, 2017	Dec. 31, 2014
Income Tax [Line Items]
U.S. federal statutory income tax rate		35.00%	35.00%	35.00%
Tax Cuts and Jobs Act of 2017, Change in Tax Rate, Deferred Tax Asset		$ 420,000
Deferred tax expenses on repatriation of foreign earnings		1,000
Income tax provisions		565,599	$ 123,769	$ (1,009,552)
Deferred tax assets, valuation allowance		61,456	$ 69,593	89,251		$ 1,044,152
Deferred tax benefit from release of valuation allowance				878,000
Deferred tax benefit related to tax receivable agreement				378,000
Deferred tax assets recorded due to net operating losses and tax credit carryforwards		239,959
Indefinite-lived carryforwards		26,000
Other certain tax credit carryforwards		$ 188,000
Certain carryforwards begin to expire		2029
Income tax examination, description		With few exceptions, the Company is no longer subject to income tax examination by foreign tax authorities and by U.S. federal, state and local tax authorities for years prior to 2012. While we are under examination in various tax jurisdictions with respect to certain open years, the Company does not expect that the result of any final determination related to these examinations will have a material impact on its financial statements. Developments with respect to such examinations are monitored on an ongoing basis and adjustments to tax liabilities are made as appropriate.
Unrecognized tax benefits, including interest and penalties recorded that may be recognized within 12 months		$ 20,000
LTBP Trust [Member]
Income Tax [Line Items]
Reduction of deferred tax benefit related to tax receivable agreement				$ 161,000
Adjustments for New Accounting Principle [Member]
Income Tax [Line Items]
Income tax provisions		$ 9,000
Deferred tax assets recorded for previously unrecognized excess tax benefits on share-based payment awards					$ 81,544
Deferred tax assets, valuation allowance					$ 12,090
Scenario Forecast [Member]
Income Tax [Line Items]
U.S. federal statutory income tax rate	21.00%

Income Taxes - Schedule of Provision (Benefit) for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Federal, current	$ 349	$ 1,766	$ 8,177
Foreign, current	64,119	54,253	78,086
State and local (primarily UBT), current	(32)	4,090	4,970
Total current	64,436	60,109	91,233
Federal, deferred	480,085	50,602	(988,900)
Foreign, deferred	12,928	1,354	(3,960)
State and local, deferred	8,150	11,704	(107,925)
Total deferred	501,163	63,660	(1,100,785)
Total	$ 565,599	$ 123,769	$ (1,009,552)

Income Taxes - Schedule of Reconciliation of U.S. Federal Statutory Income Tax Rate to Effective Tax Rates (Detail)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
U.S. federal statutory income tax rate	35.00%	35.00%	35.00%
U.S. tax reform	43.40%
Foreign source income not subject to U.S. income tax	(4.20%)	(9.30%)	419.40%
Change in U.S. federal valuation allowance	(3.40%)	(3.60%)	5477.00%
Share-based incentive compensation	(4.00%)
Foreign taxes	(0.20%)	(0.10%)	(361.60%)
State and local taxes	2.40%	3.00%	522.20%
Income of non-controlling interests	(0.30%)	(0.30%)	13.80%
Other, net	(0.20%)	(0.80%)	(31.50%)
Effective income tax rate	68.50%	23.90%	6074.30%

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Deferred Tax Assets:
Basis adjustments	$ 339,133	$ 692,430
Compensation and benefits	175,456	197,750
Net operating loss and tax credit carryforwards	239,959	285,694
Depreciation and amortization	1,537	850
Other	34,615	53,895
Gross deferred tax assets	790,700	1,230,619
Valuation allowance	(61,456)	(69,593)	$ (89,251)	$ (1,044,152)
Deferred tax assets (net of valuation allowance)	729,244	1,161,026
Deferred Tax Liabilities:
Depreciation and amortization	17,257	26,539
Compensation and benefits	23,251	5,447
Goodwill	21,749	27,932
Other	26,134	34,499
Deferred tax liabilities	88,391	94,417
Net deferred tax assets	$ 640,853	$ 1,066,609

Income Taxes - Summary of Changes in Deferred Tax Assets Valuation Allowance (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Beginning Balance	$ 69,593	$ 89,251	$ 1,044,152
Credited to provision (benefit) for income taxes	(23,670)	(15,981)	(954,487)
Charged (credited) to other comprehensive income and other	15,533	(3,677)	(414)
Ending Balance	$ 61,456	$ 69,593	$ 89,251

Income Taxes - Summary of Changes in Deferred Tax Assets Valuation Allowance (Parenthetical) (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Acquisition related deferred tax assets offset by valuation allowance		$ 2,271
Amount of unrecognized excess tax benefits offset by valuation allowance	$ 12,090

Income Taxes - Schedule of Gross Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Balance, January 1 (excluding interest and penalties of $15,392, $13,083 and $13,004, respectively)	$ 78,396	$ 77,280	$ 68,224
Increases in gross unrecognized tax benefits relating to tax positions taken during prior years	1,598	5,891
Increases in gross unrecognized tax benefits relating to tax positions taken during current years	19,823	18,438	22,212
Decreases in gross unrecognized tax benefits relating to tax positions taken during prior years	(2,961)	(5,316)	(621)
Decreases in gross unrecognized tax benefits relating to settlements with tax authorities		(1,706)
Decreases in gross unrecognized tax benefits relating to lapse of the applicable statute of limitations	(18,182)	(16,191)	(12,535)
Balance, December 31 (excluding interest and penalties of $15,136, $15,392 and $13,083, respectively)	$ 78,674	$ 78,396	$ 77,280

Income Taxes - Schedule of Gross Unrecognized Tax Benefits (Parenthetical) (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Interest and penalties	$ 15,136	$ 15,392	$ 13,083	$ 13,004

Income Taxes - Schedule of Additional Information Relating to Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Unrecognized tax benefits at the end of the year that, if recognized, would favorably affect the effective tax rate (includes interest and penalties of $15,136, $15,392 and $13,083, respectively)	$ 78,841	$ 81,564	$ 74,785
Unrecognized tax benefits that, if recognized, would not affect the effective tax rate	14,969	12,224	15,578
Interest and penalties recognized in current income tax expense (after giving effect to the reversal of interest and penalties of $6,185, $3,143 and $3,865, respectively)	$ (256)	$ 2,309	$ 79

Income Taxes - Schedule of Additional Information Relating to Unrecognized Tax Benefits (Parenthetical) (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Interest and penalties	$ 15,136	$ 15,392	$ 13,083	$ 13,004
Reversal of interest and penalties	$ 6,185	$ 3,143	$ 3,865

Net Income Per Share of Class A Common Stock - Company's Basic and Diluted Net Income Per Share and Weighted Average Shares Outstanding (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Net income attributable to Lazard Ltd - basic									$ 253,583	$ 387,698	$ 986,373
Net income attributable to Lazard Ltd - diluted									$ 253,583	$ 387,698	$ 986,373
Weighted average number of shares of Class A common stock outstanding									121,309,174	124,635,160	125,294,261
Add - adjustment for shares of Class A common stock issuable on a non-contingent basis									264,268	135,241	72,011
Weighted average number of shares of Class A common stock outstanding - basic									121,573,442	124,770,401	125,366,272
Weighted average number of incremental shares of Class A common stock issuable from share-based incentive compensation									10,906,286	7,863,229	7,878,274
Weighted average number of shares of Class A common stock outstanding - diluted									132,479,728	132,633,630	133,244,546
Net income attributable to Lazard Ltd per share of Class A common stock:
Basic	$ (0.70)	$ 0.90	$ 0.98	$ 0.88	$ 1.04	$ 0.90	$ 0.64	$ 0.53	$ 2.09	$ 3.11	$ 7.87
Diluted	$ (0.70)	$ 0.82	$ 0.91	$ 0.81	$ 0.96	$ 0.85	$ 0.61	$ 0.50	$ 1.91	$ 2.92	$ 7.40

Related Parties - Additional Information (Detail) - USD ($) $ in Thousands		1 Months Ended	3 Months Ended	12 Months Ended
	Oct. 26, 2015	Jul. 31, 2015	Jun. 30, 2015	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Related Party Transaction [Line Items]
Asset management fees					$ 1,195,550	$ 998,887	$ 1,036,821
Fees receivable					$ 487,800	$ 564,291
Tax receivable agreement, expiration terms					The term of the Amended and Restated Tax Receivable Agreement will continue until approximately 2033 or, if earlier, until all relevant tax benefits have been utilized or expired.
Provision (benefit) pursuant to tax receivable agreement			$ 961,948		$ (202,546)		$ 547,691
Percentage of beneficial interests purchased in trust		47.00%
Payments to cancel beneficial interests and extinguishment of payment obligations under the amended and restated tax receivable agreement		$ 42,222
U.S. federal statutory income tax rate					35.00%	35.00%	35.00%
Payments under tax receivable agreement					$ 789	$ 10,086	$ 1,276
Scenario Forecast [Member]
Related Party Transaction [Line Items]
U.S. federal statutory income tax rate				21.00%
Sponsored Funds [Member]
Related Party Transaction [Line Items]
Asset management fees					649,089	516,667	534,752
Fees receivable					69,107	49,944
LTBP Trust [Member]
Related Party Transaction [Line Items]
Amount of cash savings in income or franchise tax that would be realized as a result of increases in tax basis and certain other tax benefits related to the amended and restated tax receivable agreement	45.00%
Cash tax saving that may arise from tax benefits attributable to payments under the amended and restated tax receivable agreement	85.00%
Provision (benefit) pursuant to tax receivable agreement					(202,546)		547,691
Pre-tax gain on extinguishment of obligations under tax receivable agreement							420,792
Reduction of deferred tax benefit related to tax receivable agreement							$ 161,000
Reduction in tax receivable agreement obligation					202,546
Cumulative liability relating to obligations under Amended and Restated Tax Receivable Agreement					310,275	$ 513,610
Payments under tax receivable agreement					$ 789

Regulatory Authorities - Additional Information (Detail)	Dec. 31, 2017 USD ($)
LFNY [Member]
Regulatory Requirements [Line Items]
Specified fixed percentage, minimum required capital	6.67%
Minimum net capital requirement as defined under exchange act	$ 100,000
Regulatory capital	156,289,000
Regulatory capital in excess of minimum requirement	$ 151,311,000
Aggregate indebtedness to net capital ratio	0.48
LFNY [Member] \| Maximum [Member]
Regulatory Requirements [Line Items]
Aggregate indebtedness to net capital ratio	15
U.K. Subsidiaries [Member]
Regulatory Requirements [Line Items]
Regulatory capital	$ 192,717,000
Regulatory capital in excess of minimum requirement	173,756,000
CFLF [Member]
Regulatory Requirements [Line Items]
Regulatory capital	140,353,000
Regulatory capital in excess of minimum requirement	85,904,000
Combined European Regulated Group [Member]
Regulatory Requirements [Line Items]
Regulatory capital	170,933,000
Regulatory capital in excess of minimum requirement	68,025,000
Other U.S. and Non-U.S. Subsidiaries [Member]
Regulatory Requirements [Line Items]
Regulatory capital	162,440,000
Regulatory capital in excess of minimum requirement	$ 134,275,000

Segment Information - Additional Information (Detail)	12 Months Ended
Segment Information - Additional Information (Detail)	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Sales Revenue, Net [Member] \| Customer Concentration Risk [Member]
Segment Reporting Information [Line Items]
Individual clients did not constitute more than a specific percentage of net revenue	10.00%	10.00%	10.00%

Segment Information - Segment's Contribution with Respect to Net Revenue, Operating Expenses, Operating Income (Loss) and Total Assets (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Net Revenue	$ 678,808	$ 624,859	$ 717,180	$ 623,464	$ 691,565	$ 608,908	$ 534,680	$ 498,218	$ 2,644,311	$ 2,333,371	$ 2,353,608
Operating Expenses	320,272	480,647	544,679	473,267	534,709	459,916	421,444	399,841	1,818,865	1,815,910	2,370,228
Operating Income (Loss)	358,536	$ 144,212	$ 172,501	$ 150,197	156,856	$ 148,992	$ 113,236	$ 98,377	825,446	517,461	(16,620)
Total Assets	4,928,677				4,556,508				4,928,677	4,556,508	4,477,774
Depreciation and amortization of property									31,498	33,264	32,785
Operating Segments [Member] \| Financial Advisory Segment [Member]
Segment Reporting Information [Line Items]
Net Revenue									1,387,682	1,301,044	1,279,628
Operating Expenses									1,143,586	1,017,055	1,005,837
Operating Income (Loss)									244,096	283,989	273,791
Total Assets	843,142				907,035				843,142	907,035	763,374
Depreciation and amortization of property									6,596	5,661	4,412
Operating Segments [Member] \| Asset Management Segment [Member]
Segment Reporting Information [Line Items]
Net Revenue									1,255,820	1,051,316	1,111,105
Operating Expenses									810,870	769,737	736,798
Operating Income (Loss)									444,950	281,579	374,307
Total Assets	756,398				645,653				756,398	645,653	640,034
Depreciation and amortization of property									2,830	3,666	2,957
Corporate [Member]
Segment Reporting Information [Line Items]
Net Revenue									809	(18,989)	(37,125)
Operating Expenses									(135,591)	29,118	627,593
Operating Income (Loss)									136,400	(48,107)	(664,718)
Total Assets	$ 3,329,137				$ 3,003,820				3,329,137	3,003,820	3,074,366
Depreciation and amortization of property									$ 22,072	$ 23,937	$ 25,416

Segment Information - Segment's Contribution with Respect to Net Revenue, Operating Expenses, Operating Income (Loss) and Total Assets (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2017	Dec. 31, 2015
Segment Reporting Information [Line Items]
Provision (benefit) pursuant to tax receivable agreement	$ 961,948	$ (202,546)	$ 547,691
LTBP Trust [Member]
Segment Reporting Information [Line Items]
Provision (benefit) pursuant to tax receivable agreement		(202,546)	547,691
Corporate [Member] \| LTBP Trust [Member]
Segment Reporting Information [Line Items]
Provision (benefit) pursuant to tax receivable agreement		$ (202,546)	$ 547,691

Segment Information - Schedule of Revenue from External Customers and Identifiable Assets, by Geographical Areas (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Net Revenue	$ 678,808	$ 624,859	$ 717,180	$ 623,464	$ 691,565	$ 608,908	$ 534,680	$ 498,218	$ 2,644,311	$ 2,333,371	$ 2,353,608
Operating Income (Loss)	358,536	$ 144,212	$ 172,501	$ 150,197	156,856	$ 148,992	$ 113,236	$ 98,377	825,446	517,461	(16,620)
Identifiable Assets	4,928,677				4,556,508				4,928,677	4,556,508	4,477,774
Americas [Member]
Segment Reporting Information [Line Items]
Net Revenue									1,558,070	1,399,285	1,322,898
Operating Income (Loss)									596,044	335,887	(259,538)
Identifiable Assets	2,600,412				3,015,267				2,600,412	3,015,267	2,811,850
EMEA [Member]
Segment Reporting Information [Line Items]
Net Revenue									903,525	795,932	813,136
Operating Income (Loss)									193,781	168,745	163,612
Identifiable Assets	2,039,385				1,286,149				2,039,385	1,286,149	1,405,555
Asia Pacific [Member]
Segment Reporting Information [Line Items]
Net Revenue									182,716	138,154	217,574
Operating Income (Loss)									35,621	12,829	79,306
Identifiable Assets	$ 288,880				$ 255,092				$ 288,880	$ 255,092	$ 260,369

Segment Information - Schedule of Revenue from External Customers and Identifiable Assets, by Geographical Areas (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2017	Dec. 31, 2015
Segment Reporting Information [Line Items]
Provision (benefit) pursuant to tax receivable agreement	$ 961,948	$ (202,546)	$ 547,691
LTBP Trust [Member]
Segment Reporting Information [Line Items]
Provision (benefit) pursuant to tax receivable agreement		(202,546)	547,691
Americas [Member] \| LTBP Trust [Member]
Segment Reporting Information [Line Items]
Provision (benefit) pursuant to tax receivable agreement		$ (202,546)	$ 547,691

Supplemental Financial Information - Quarterly Results - Schedule of Quarterly Financial Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Selected Quarterly Financial Information [Abstract]
Net Revenue	$ 678,808	$ 624,859	$ 717,180	$ 623,464	$ 691,565	$ 608,908	$ 534,680	$ 498,218	$ 2,644,311	$ 2,333,371	$ 2,353,608
Operating expenses	320,272	480,647	544,679	473,267	534,709	459,916	421,444	399,841	1,818,865	1,815,910	2,370,228
Operating Income (Loss)	358,536	144,212	172,501	150,197	156,856	148,992	113,236	98,377	825,446	517,461	(16,620)
NET INCOME	(82,954)	111,470	120,901	110,430	128,987	112,618	81,364	70,723	259,847	393,692	992,932
Net Income Attributable to Noncontrolling Interests	604	2,260	523	2,877	1,005	82	1,007	3,900	6,264	5,994	6,559
Net income (loss) attributable to Lazard Ltd	$ (83,558)	$ 109,210	$ 120,378	$ 107,553	$ 127,982	$ 112,536	$ 80,357	$ 66,823	$ 253,583	$ 387,698	$ 986,373
NET INCOME PER SHARE OF COMMON STOCK:
Basic	$ (0.70)	$ 0.90	$ 0.98	$ 0.88	$ 1.04	$ 0.90	$ 0.64	$ 0.53	$ 2.09	$ 3.11	$ 7.87
Diluted	(0.70)	0.82	0.91	0.81	0.96	0.85	0.61	0.50	1.91	2.92	7.40
DIVIDENDS DECLARED PER SHARE OF COMMON STOCK	$ 0.41	$ 0.41	$ 0.41	$ 1.58	$ 0.38	$ 0.38	$ 0.38	$ 1.55	$ 2.81	$ 2.69	$ 2.35

Schedule I - Condensed Statements of Financial Condition (Parent Company Only) (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
ASSETS
Cash and cash equivalents	$ 1,483,836	$ 1,158,785	$ 1,132,083	$ 1,066,580
Investments in subsidiaries, equity method		222
Other assets	228,144	184,499
Total Assets	4,928,677	4,556,508	4,477,774
Liabilities:
Other liabilities	573,588	537,446
Total Liabilities	3,669,772	3,262,695
Commitments and contingencies
Common stock:
Class A, par value $.01 per share (500,000,000 shares authorized; 129,766,091 shares issued at December 31, 2017 and 2016, including shares held by subsidiaries as indicated below)	1,298	1,298
Additional paid-in-capital	788,140	688,231
Retained earnings	1,080,413	1,134,186
Accumulated other comprehensive loss, net of tax	(232,518)	(314,222)
Stockholders' equity subtotal before common stock held by subsidiaries and Noncontrolling interests, total	1,637,333	1,509,493
Class A common stock held by subsidiaries, at cost (10,747,142 and 7,628,786 shares at December 31, 2017 and 2016, respectively)	(437,530)	(273,506)
Total stockholders’ equity	1,199,803	1,235,987
Total Liabilities and Stockholders’ Equity	4,928,677	4,556,508
Series A Preferred Stock [Member]
Preferred stock:
Preferred stock
Series B Preferred Stock [Member]
Preferred stock:
Preferred stock
Parent Company [Member]
ASSETS
Cash and cash equivalents	3,921	3,916	$ 5,904	$ 7,482
Investments in subsidiaries, equity method	(1,061,259)	(534,642)
Due from subsidiaries	2,259,112	1,766,875
Other assets		13
Total Assets	1,201,774	1,236,162
Liabilities:
Due to subsidiaries	1,847	65
Other liabilities	124	110
Total Liabilities	1,971	175
Commitments and contingencies
Common stock:
Class A, par value $.01 per share (500,000,000 shares authorized; 129,766,091 shares issued at December 31, 2017 and 2016, including shares held by subsidiaries as indicated below)	1,298	1,298
Additional paid-in-capital	788,140	688,231
Retained earnings	1,080,413	1,134,186
Accumulated other comprehensive loss, net of tax	(232,518)	(314,222)
Stockholders' equity subtotal before common stock held by subsidiaries and Noncontrolling interests, total	1,637,333	1,509,493
Class A common stock held by subsidiaries, at cost (10,747,142 and 7,628,786 shares at December 31, 2017 and 2016, respectively)	(437,530)	(273,506)
Total stockholders’ equity	1,199,803	1,235,987
Total Liabilities and Stockholders’ Equity	1,201,774	1,236,162
Parent Company [Member] \| Series A Preferred Stock [Member]
Preferred stock:
Preferred stock
Parent Company [Member] \| Series B Preferred Stock [Member]
Preferred stock:
Preferred stock

Schedule I - Condensed Statements of Financial Condition (Parent Company Only) (Parenthetical) (Detail) - $ / shares	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	15,000,000	15,000,000
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	129,766,091	129,766,091
Common stock held by subsidiaries, shares	10,747,142	7,628,786
Series A Preferred Stock [Member]
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0	7,921
Series B Preferred Stock [Member]
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0	0
Parent Company [Member]
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	15,000,000	15,000,000
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	129,766,091	129,766,091
Common stock held by subsidiaries, shares	10,747,142	7,628,786
Parent Company [Member] \| Series A Preferred Stock [Member]
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Parent Company [Member] \| Series B Preferred Stock [Member]
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0

Schedule I - Condensed Statements of Operations (Parent Company Only) (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
REVENUE
Total revenue									$ 2,697,829	$ 2,383,663	$ 2,404,767
OPERATING EXPENSES
Professional services									47,932	45,512	49,529
Other									44,069	41,219	99,142
Total operating expenses	$ 320,272	$ 480,647	$ 544,679	$ 473,267	$ 534,709	$ 459,916	$ 421,444	$ 399,841	1,818,865	1,815,910	2,370,228
NET INCOME ATTRIBUTABLE TO LAZARD LTD	$ (83,558)	$ 109,210	$ 120,378	$ 107,553	$ 127,982	$ 112,536	$ 80,357	$ 66,823	253,583	387,698	986,373
Parent Company [Member]
REVENUE
Equity in earnings of subsidiaries									145,008	326,366	931,036
Interest and other income									110,381	63,019	57,258
Total revenue									255,389	389,385	988,294
OPERATING EXPENSES
Professional services									1,692	1,580	1,779
Other									114	107	142
Total operating expenses									1,806	1,687	1,921
NET INCOME ATTRIBUTABLE TO LAZARD LTD									$ 253,583	$ 387,698	$ 986,373

Schedule I - Condensed Statements of Comprehensive Income (Parent Company Only) (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
NET INCOME	$ (83,558)	$ 109,210	$ 120,378	$ 107,553	$ 127,982	$ 112,536	$ 80,357	$ 66,823	$ 253,583	$ 387,698	$ 986,373
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX:
Currency translation adjustments									71,669	(57,920)	(51,182)
Employee benefit plans:
Actuarial gain (loss) (net of tax expense (benefit) of $(3,507), $(5,205) and $5,644 for the years ended December 31, 2017, 2016 and 2015, respectively)									2,085	(24,473)	11,283
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX									81,705	(79,867)	(33,590)
COMPREHENSIVE INCOME ATTRIBUTABLE TO LAZARD LTD									335,287	307,832	952,783
Parent Company [Member]
NET INCOME									253,583	387,698	986,373
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX:
Currency translation adjustments									71,668	(57,919)	(51,182)
Employee benefit plans:
Actuarial gain (loss) (net of tax expense (benefit) of $(3,507), $(5,205) and $5,644 for the years ended December 31, 2017, 2016 and 2015, respectively)									2,085	(24,473)	11,283
Adjustments for items reclassified to earnings (net of tax expense of $2,220, $1,757 and $1,507 for the years ended December 31, 2017, 2016 and 2015, respectively)									7,951	2,526	6,309
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX									81,704	(79,866)	(33,590)
COMPREHENSIVE INCOME ATTRIBUTABLE TO LAZARD LTD									$ 335,287	$ 307,832	$ 952,783

Schedule I - Condensed Statements of Comprehensive Income (Parent Company Only) (Parenthetical) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Tax expense (benefit) on actuarial gain (loss), employee benefit plans	$ (3,507)	$ (5,205)	$ 5,644
Tax expense, adjustment for items reclassified to earnings, employee benefit plans	2,220	1,757	1,507
Parent Company [Member]
Tax expense (benefit) on actuarial gain (loss), employee benefit plans	(3,507)	(5,205)	5,644
Tax expense, adjustment for items reclassified to earnings, employee benefit plans	$ 2,220	$ 1,757	$ 1,507

Schedule I - Condensed Statements of Cash Flows (Parent Company Only) (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
NET INCOME	$ (83,558)	$ 109,210	$ 120,378	$ 107,553	$ 127,982	$ 112,536	$ 80,357	$ 66,823	$ 253,583	$ 387,698	$ 986,373
Adjustments to reconcile net income to net cash provided by operating activities:
Net cash provided by operating activities									1,015,442	601,287	887,296
CASH FLOWS FROM FINANCING ACTIVITIES:
Class A common stock dividends									341,450	336,138	290,684
Net cash used in financing activities									(740,393)	(486,952)	(746,804)
NET INCREASE IN CASH AND CASH EQUIVALENTS									325,051	26,702	65,503
CASH AND CASH EQUIVALENTS—January 1				1,158,785				1,132,083	1,158,785	1,132,083	1,066,580
CASH AND CASH EQUIVALENTS—December 31	1,483,836				1,158,785				1,483,836	1,158,785	1,132,083
Parent Company [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
NET INCOME									253,583	387,698	986,373
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in earnings of subsidiaries									(145,008)	(326,366)	(931,036)
Dividends received from subsidiaries									63,822
Changes in due to/from subsidiaries									169,056	273,051	233,519
Changes in other operating assets and liabilities									27	(233)	250
Net cash provided by operating activities									341,480	334,150	289,106
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital contribution to subsidiaries									(25)
Net cash used in investing activities									(25)
CASH FLOWS FROM FINANCING ACTIVITIES:
Class A common stock dividends									(341,450)	(336,138)	(290,684)
Net cash used in financing activities									(341,450)	(336,138)	(290,684)
NET INCREASE IN CASH AND CASH EQUIVALENTS									5	(1,988)	(1,578)
CASH AND CASH EQUIVALENTS—January 1				$ 3,916				$ 5,904	3,916	5,904	7,482
CASH AND CASH EQUIVALENTS—December 31	$ 3,921				$ 3,916				$ 3,921	$ 3,916	$ 5,904

Schedule I - Basis of Presentation (Parent Company Only) (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($)
Organization And Basis Of Presentation [Line Items]
Gain on acquisition of portion of business already owned	$ 12,668
Parent Company [Member]
Organization And Basis Of Presentation [Line Items]
Gain on acquisition of portion of business already owned	$ 12,668