Entity Central Index Key Document and entity information abstract. Document And Entity Information [Abstract] Document Information [Table] Document Information [Table] Consolidated Entities Consolidated Entities [Axis] Consolidated Entities Consolidated Entities [Domain] Subsidiaries of Lazard Ltd [Member] Subsidiaries [Member] Document Information [Line Items] Document Information [Line Items] Document Type Document Type Amendment Flag Amendment Flag Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Trading Symbol Trading Symbol Entity Registrant Name Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Entity Common Stock, Shares Outstanding Entity Common Stock Shares Outstanding Represents deposits with banks and investments with a maturity of less than 90 days. Receivables from customers related to collateralized lending activities, loans granted by bank to third party clients, managing directors, employees in the ordinary course of business, receivables from brokers-dealers and clearing organizations relating to unsettled securities transactions and receivables from related parties. Stockholders equity subtotal before common stock held by subsidiaries and noncontrolling interests. Deposits and other customer payables principally related to customer-related interest-bearing time and demand deposits, short-term inter-bank borrowing with registered banks, amounts due on collateralized borrowing activities and other related party payables. Payable pursuant to the tax receivable agreement. Statement Of Financial Position [Abstract] Statement [Table] Statement [Table] Class of Stock Statement Class Of Stock [Axis] Class of Stock Class Of Stock [Domain] Series A Preferred Stock [Member] Series A Preferred Stock [Member] Series B Preferred Stock [Member] Series B Preferred Stock [Member] Related Party Related Party Transactions By Related Party [Axis] Related Party Related Party [Domain] LTBP Trust. LTBP Trust [Member] Ltbp Trust [Member] Statement [Line Items] Statement [Line Items] ASSETS Assets [Abstract] Cash and cash equivalents Cash And Cash Equivalents At Carrying Value Deposits with banks and short-term investments Deposits With Banks And Short Term Investments Cash deposited with clearing organizations and other segregated cash Cash And Securities Segregated Under Federal And Other Regulations Receivables (net of allowance for doubtful accounts of $27,464 and $16,386 at September 30, 2017 and December 31, 2016, respectively): Accounts Receivable Net [Abstract] Fees Accrued Fees And Other Revenue Receivable Customers and other Receivables From Customers And Other Total receivables, net Accounts Receivable Net Investments Investments Property (net of accumulated amortization and depreciation of $314,717 and $286,001 at September 30, 2017 and December 31, 2016, respectively) Property Plant And Equipment Net Goodwill and other intangible assets (net of accumulated amortization of $62,610 and $60,080 at September 30, 2017 and December 31, 2016, respectively) Intangible Assets Net Including Goodwill Deferred tax assets Deferred Income Tax Assets Net Other assets Other Assets Total Assets Assets Allowance for doubtful accounts receivables Allowance For Doubtful Accounts Receivable Property, accumulated amortization and depreciation Accumulated Depreciation Depletion And Amortization Property Plant And Equipment Other intangible assets, accumulated amortization Finite Lived Intangible Assets Accumulated Amortization LIABILITIES AND STOCKHOLDERS’ EQUITY Liabilities And Stockholders Equity [Abstract] Liabilities: Liabilities [Abstract] Deposits and other customer payables Deposits And Other Customer Payables Accrued compensation and benefits Employee Related Liabilities Current And Noncurrent Senior debt Long Term Debt Tax receivable agreement obligation Payable Pursuant To Tax Receivable Agreement Deferred tax liabilities Deferred Income Tax Liabilities Net Other liabilities Other Liabilities Total Liabilities Liabilities Commitments and contingencies Commitments And Contingencies STOCKHOLDERS’ EQUITY Stockholders Equity [Abstract] Preferred stock: Preferred Stock Number Of Shares Par Value And Other Disclosures [Abstract] Preferred stock Preferred Stock Value Common stock: Common Stock Number Of Shares Par Value And Other Disclosures [Abstract] Class A, par value $.01 per share (500,000,000 shares authorized; 129,766,091 shares issued at September 30, 2017 and December 31, 2016, including shares held by subsidiaries as indicated below) Common Stock Value Additional paid-in-capital Additional Paid In Capital Common Stock Retained earnings Retained Earnings Accumulated Deficit Accumulated other comprehensive loss, net of tax Accumulated Other Comprehensive Income Loss Net Of Tax Stockholders' equity subtotal before common stock held by subsidiaries and Noncontrolling interests, total Stockholders Equity Before Common Stock Held By Subsidiaries And Noncontrolling Interests Class A common stock held by subsidiaries, at cost (9,647,663 and 7,628,786 shares at September 30, 2017 and December 31, 2016, respectively) Common Stock Held By Subsidiary Total Lazard Ltd Stockholders’ Equity Stockholders Equity Noncontrolling interests Minority Interest Total Stockholders’ Equity Stockholders Equity Including Portion Attributable To Noncontrolling Interest Total Liabilities and Stockholders’ Equity Liabilities And Stockholders Equity Number of shares held by subsidiary, which are purchased for the purpose of granting the shares to senior employees as part of an employee stock option plan approved by the Entity's Board of Directors. Preferred stock, par value Preferred Stock Par Or Stated Value Per Share Preferred stock, shares authorized Preferred Stock Shares Authorized Preferred stock, shares issued Preferred Stock Shares Issued Preferred stock, shares outstanding Preferred Stock Shares Outstanding Common stock, par value Common Stock Par Or Stated Value Per Share Common stock, shares authorized Common Stock Shares Authorized Common stock, shares issued Common Stock Shares Issued Common stock held by subsidiaries, shares Common Stock Held By Subsidiary Shares Includes advisory fees earned for providing advice and analysis related to corporate mergers, acquisitions, divestures, and funding. Also includes restructuring advisory fees earned involving a client or a client's portfolio company in bankruptcy, in financial distress and/or is significantly over leveraged. Consisting of fees paid for outsourced services and asset management related expenses for mutual fund servicing, fund administration by third parties. In addition, custodial, clearing and settlement costs. Amount of amortization and other acquisition related costs. Income Statement [Abstract] REVENUE Revenues Net Of Interest Expense [Abstract] Investment banking and other advisory fees Investment Banking And Other Advisory Fees Asset management fees Asset Management Fees1 Interest income Interest Income Operating Other Other Income Total revenue Revenues Interest expense Interest Expense Net revenue Revenues Net Of Interest Expense OPERATING EXPENSES Costs And Expenses [Abstract] Compensation and benefits Labor And Related Expense Occupancy and equipment Occupancy Net Marketing and business development Business Development Technology and information services Information Technology And Data Processing Professional services Professional Fees Fund administration and outsourced services Fund Administration And Outsourced Services Amortization and other acquisition-related costs Amortization And Other Acquisition Related Costs Other Other Expenses Total operating expenses Costs And Expenses OPERATING INCOME Operating Income Loss Provision for income taxes Income Tax Expense Benefit NET INCOME Profit Loss LESS - NET INCOME ATTRIBUTABLE TO NONCONTROLLING INTERESTS Net Income Loss Attributable To Noncontrolling Interest NET INCOME ATTRIBUTABLE TO LAZARD LTD Net Income Loss WEIGHTED AVERAGE SHARES OF COMMON STOCK OUTSTANDING: Weighted Average Number Of Shares Outstanding [Abstract] Basic Weighted Average Number Of Shares Outstanding Basic Diluted Weighted Average Number Of Diluted Shares Outstanding NET INCOME PER SHARE OF COMMON STOCK: Earnings Per Share [Abstract] Basic Earnings Per Share Basic Diluted Earnings Per Share Diluted DIVIDENDS DECLARED PER SHARE OF COMMON STOCK Common Stock Dividends Per Share Declared Statement Of Income And Comprehensive Income [Abstract] NET INCOME OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX: Other Comprehensive Income Loss Net Of Tax Period Increase Decrease [Abstract] Currency translation adjustments (including a tax benefit of $221 for the three months ended September 30, 2016 and $3,090 for the nine months ended September 30, 2016) Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax Employee benefit plans: Other Comprehensive Income Defined Benefit Plans Adjustment Net Of Tax Period Increase Decrease [Abstract] Actuarial loss (net of tax benefit of $1,197 and $17 for the three months ended September 30, 2017 and 2016, respectively, and $3,673 and $315 for the nine months ended September 30, 2017 and 2016, respectively) Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Net Of Tax Adjustment for items reclassified to earnings (net of tax expense of $204 and $375 for the three months ended September 30, 2017 and 2016, respectively, and $676 and $1,171 for the nine months ended September 30, 2017 and 2016, respectively) Other Comprehensive Income Loss Reclassification Adjustment From A O C I Pension And Other Postretirement Benefit Plans Net Of Tax OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX Other Comprehensive Income Loss Net Of Tax COMPREHENSIVE INCOME Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest LESS - COMPREHENSIVE INCOME ATTRIBUTABLE TO NONCONTROLLING INTERESTS Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest COMPREHENSIVE INCOME ATTRIBUTABLE TO LAZARD LTD Comprehensive Income Net Of Tax Currency translation adjustments, tax benefit Other Comprehensive Income Loss Foreign Currency Translation Adjustment Tax Tax benefit on actuarial loss, employee benefit plans Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Tax Tax expense, adjustment for items reclassified to earnings, employee benefit plans Other Comprehensive Income Loss Reclassification Adjustment From A O C I Pension And Other Postretirement Benefit Plans Tax Amortization of deferred expenses and share- based compensation. The increase (decrease) during the reporting period in deposits with banks and short term investments. The net change during the reporting period in the amount of cash subject to withdrawal restrictions, restricted deposits held as compensating balances, and cash and securities segregated in compliance with regulations (such as cash deposited in a special reserve account for the exclusive benefit of customers pursuant). The amount of increase (decrease) during the period in deposits and other customer payables. Represents the net change of obligations incurred through that date and payable for obligations related to services received from employees such as accrued salaries, bonuses, payroll taxes and fringe benefits and the sum of other liabilities not individually reported in the financial statements or separately disclosed in the notes. The cash inflow from other financing activities. This element is used when there is not a more specific and appropriate element in the taxonomy. Amount of cash outflow made in accordance with the tax receivable agreement obligation. The cash outflow from the settlement of share-based incentive compensation. The cash outflow from other financing activities. This element is used when there is not a more specific and appropriate element in the taxonomy. Proceeds from financing activities. Payments for financing activities. Statement Of Cash Flows [Abstract] CASH FLOWS FROM OPERATING ACTIVITIES: Net Cash Provided By Used In Operating Activities Continuing Operations [Abstract] Net income Adjustments to reconcile net income to net cash provided by (used in) operating activities: Adjustments Noncash Items To Reconcile Net Income Loss To Cash Provided By Used In Operating Activities [Abstract] Depreciation and amortization of property Depreciation Depletion And Amortization Amortization of deferred expenses and share-based incentive compensation Amortization Of Deferred Expenses And Sharebased Incentive Compensation Deferred tax provision Deferred Income Tax Expense Benefit (Increase) decrease in operating assets: Increase Decrease In Operating Assets [Abstract] Deposits with banks and short-term investments Increase Decrease In Deposits With Banks And Short Term Investments Cash deposited with clearing organizations and other segregated cash Increase Decrease In Cash And Securities Segregated Under Federal And Other Regulations1 Receivables-net Increase Decrease In Receivables Investments Increase Decrease In Financial Instruments Used In Operating Activities Other assets Increase Decrease In Other Operating Assets Increase (decrease) in operating liabilities: Increase Decrease In Operating Liabilities [Abstract] Deposits and other payables Increase Decrease In Deposits And Other Customer Payables Accrued compensation and benefits and other liabilities Increase Decrease In Accrued Compensation And Benefits And Other Liabilities Net cash provided by operating activities Net Cash Provided By Used In Operating Activities Continuing Operations CASH FLOWS FROM INVESTING ACTIVITIES: Net Cash Provided By Used In Investing Activities Continuing Operations [Abstract] Additions to property Payments To Acquire Property Plant And Equipment Disposals of property Proceeds From Sale Of Property Plant And Equipment Net cash used in investing activities Net Cash Provided By Used In Investing Activities Continuing Operations CASH FLOWS FROM FINANCING ACTIVITIES: Net Cash Provided By Used In Financing Activities Continuing Operations [Abstract] Proceeds from: Proceeds From Financing Activities [Abstract] Contributions from noncontrolling interests Proceeds From Minority Shareholders Excess tax benefits from share-based incentive compensation Excess Tax Benefit From Share Based Compensation Financing Activities Other financing activities Proceeds From Other Financing Activities Payments for: Payments For Financing Activities [Abstract] Capital lease obligations Repayments Of Long Term Capital Lease Obligations Distributions to noncontrolling interests Payments To Minority Shareholders Payments under tax receivable agreement Payments For Tax Receivable Agreement Obligation Purchase of Class A common stock Payments For Repurchase Of Common Stock Class A common stock dividends Payments Of Dividends Common Stock Settlement of vested share-based incentive compensation Settlement Of Share Based Incentive Compensation Other financing activities Payments For Other Financing Activities Net cash used in financing activities Net Cash Provided By Used In Financing Activities Continuing Operations EFFECT OF EXCHANGE RATE CHANGES ON CASH Effect Of Exchange Rate On Cash And Cash Equivalents Continuing Operations NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS Cash And Cash Equivalents Period Increase Decrease CASH AND CASH EQUIVALENTS—January 1 CASH AND CASH EQUIVALENTS—September 30 Value of shares delivered from treasury stock during the period as a result of an equity-based compensation plan and related tax benefit (expense). Number of shares delivered from treasury stock during the period as a result of an equity-based compensation plan and related tax benefit (expense). Value of stock issued or issuable in connection with acquisitions and subsidiary merger and related amortization. Business acquisitions and related equity transactions. Statement Of Stockholders Equity [Abstract] Equity Components Statement Equity Components [Axis] Equity Component Equity Component [Domain] Common Stock [Member] Common Stock [Member] Additional Paid-In-Capital [Member] Additional Paid In Capital [Member] Retained Earnings [Member] Retained Earnings [Member] Accumulated Other Comprehensive Income (Loss), Net of Tax [Member] Accumulated Other Comprehensive Income [Member] Common Stock Held by Subsidiary Class A Common Stock Held By Subsidiaries [Member] Common Stock Held By Subsidiary [Member] Total Lazard Ltd Stockholders' Equity [Member] Parent [Member] Noncontrolling Interests [Member] Noncontrolling Interest [Member] Balance Balance (in shares) Shares Outstanding Adjustment for the cumulative effect on prior years from the adoption of new accounting guidance related to share-based incentive compensation Cumulative Effect Of New Accounting Principle In Period Of Adoption Balance, as adjusted Stockholders Equity Including Portion Attributable To Noncontrolling Interest Adjusted Balance1 Comprehensive income (loss): Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest [Abstract] Other comprehensive income (loss) - net of tax Amortization of share-based incentive compensation Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value Dividend-equivalents Dividends Sharebased Compensation Stock Class A common stock dividends Dividends Common Stock Purchase of Class A common stock Stock Repurchased During Period Value Purchase of Class A common stock (in shares) Stock Repurchased During Period Shares Delivery of Class A common stock in connection with share-based incentive compensation and related tax expense/benefit Delivery Of Shares From Treasury Stock During The Period Net Of Tax On Share Based Compensation Delivery of Class A common stock in connection with share-based incentive compensation and related tax expense/benefit (in shares) Delivery Of Shares From Treasury Stock During The Period Net Of Tax On Share Based Compensation Shares Business acquisitions and related equity transactions: Business Acquisitions And Related Equity Transactions [Abstract] Delivery of Class A common stock and related tax benefit Stock Issued During Period Value Acquisitions Delivery of Class A common stock and related tax benefit (in shares) Stock Issued During Period Shares Acquisitions Class A common stock issuable (including related amortization) Stock Issued Issuable During Period Value Business Acquisitions Mergers And Amortization Distributions to noncontrolling interests, net Minority Interest Decrease From Distributions To Noncontrolling Interest Holders Other Adjustments To Additional Paid In Capital Other Other Stockholders Equity Other Balance Balance (in shares) Tax benefit (expense) from stock issued in connection with share-based incentive compensation. Tax benefit (expense) on stock issued during period acquisitions. Tax (expense) benefit related to delivery of Class A Common Stock in connection with share-based incentive compensation Tax Benefit Expense From Stock Issued In Connection With Sharebased Incentive Compensation Tax benefit related to delivery of Class A Common Stock Tax Benefit Expense On Stock Issued During Period Acquisitions Organization Consolidation And Presentation Of Financial Statements [Abstract] Organization and Basis of Presentation Organization Consolidation And Presentation Of Financial Statements Disclosure [Text Block] New Accounting Pronouncements And Changes In Accounting Principles [Abstract] Recent Accounting Developments New Accounting Pronouncements And Changes In Accounting Principles [Text Block] Receivables [Abstract] Receivables Loans Notes Trade And Other Receivables Disclosure [Text Block] Investments Schedule [Abstract] Investments Investment [Text Block] Fair Value Disclosures [Abstract]