Lazard 10-Q 31 Oct 17 2017 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2017	Oct. 20, 2017
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q3
Trading Symbol	LZD
Entity Registrant Name	LAZARD GROUP LLC
Entity Central Index Key	1,326,141
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding	0
Managing Member Interests [Member]
Document Information [Line Items]
Membership Interests, Outstanding		2

Condensed Consolidated Statemen

Condensed Consolidated Statements of Financial Condition - USD ($) $ in Thousands		Sep. 30, 2017	Dec. 31, 2016
ASSETS
Cash and cash equivalents		$ 1,241,702	$ 1,131,440
Deposits with banks and short-term investments		652,484	419,668
Cash deposited with clearing organizations and other segregated cash		35,369	29,030
Receivables (net of allowance for doubtful accounts of $27,464 and $16,386 at September 30, 2017 and December 31, 2016, respectively):
Fees		450,968	564,291
Customers and other		100,617	73,991
Lazard Ltd subsidiaries		19,434	28,702
Total receivables, net		571,019	666,984
Investments		426,948	459,422
Property (net of accumulated amortization and depreciation of $314,708 and $285,997 at September 30, 2017 and December 31, 2016, respectively)		200,702	208,997
Goodwill and other intangible assets (net of accumulated amortization of $60,918 and $59,618 at September 30, 2017 and December 31, 2016, respectively)		368,331	358,982
Deferred tax assets		59,814	59,767
Other assets		219,731	181,694
Total Assets		3,776,100	3,515,984
Liabilities:
Deposits and other customer payables		702,014	472,283
Accrued compensation and benefits		488,858	539,944
Senior debt		1,189,936	1,188,600
Payable to Lazard Ltd subsidiaries		64,166	60,898
Deferred tax liabilities		4,009	8,625
Other liabilities		549,233	509,494
Total Liabilities		2,998,216	2,779,844
Commitments and contingencies
MEMBERS’ EQUITY
Members' equity (net of 8,716,667 and 6,697,790 shares of Lazard Ltd Class A common stock, at a cost of $353,972 and $244,518 at September 30, 2017 and December 31, 2016, respectively)		942,454	949,669
Accumulated other comprehensive loss, net of tax		(224,632)	(270,775)
Total Lazard Group LLC Members' Equity		717,822	678,894
Noncontrolling interests		60,062	57,246
Total Members’ Equity	[1]	777,884	736,140
Total Liabilities and Members’ Equity		$ 3,776,100	$ 3,515,984
[1]	At both January 1, 2017 and September 30, 2017, in addition to profit participation interests, there were two managing member interests.

Condensed Consolidated Stateme3

Condensed Consolidated Statements of Financial Condition (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts receivables	$ 27,464	$ 16,386
Property, accumulated amortization and depreciation	314,708	285,997
Other intangible assets, accumulated amortization	$ 60,918	$ 59,618
Lazard Ltd common stock, shares	8,716,667	6,697,790
Lazard Ltd common stock, cost	$ 353,972	$ 244,518

Condensed Consolidated Stateme4

Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
REVENUE
Investment banking and other advisory fees	$ 305,530	$ 343,154	$ 1,050,471	$ 894,906
Asset management fees	301,719	254,551	868,522	729,679
Interest income	1,615	1,146	4,959	3,881
Other	29,155	22,094	81,092	49,318
Total revenue	638,019	620,945	2,005,044	1,677,784
Interest expense	14,248	13,068	42,770	38,592
Net revenue	623,771	607,877	1,962,274	1,639,192
OPERATING EXPENSES
Compensation and benefits	359,294	353,468	1,134,142	958,962
Occupancy and equipment	29,082	26,962	87,334	81,114
Marketing and business development	20,045	16,891	63,463	60,456
Technology and information services	31,371	24,175	87,329	71,402
Professional services	11,005	9,672	31,559	29,488
Fund administration and outsourced services	18,292	17,097	52,539	46,427
Amortization and other acquisition-related costs	335	746	1,946	1,720
Other	9,153	9,233	30,510	28,609
Total operating expenses	478,577	458,244	1,488,822	1,278,178
OPERATING INCOME	145,194	149,633	473,452	361,014
Provision for income taxes	27,367	21,653	81,802	49,110
NET INCOME	117,827	127,980	391,650	311,904
LESS - NET INCOME ATTRIBUTABLE TO NONCONTROLLING INTERESTS	2,261	83	5,660	4,989
NET INCOME ATTRIBUTABLE TO LAZARD GROUP LLC	$ 115,566	$ 127,897	$ 385,990	$ 306,915

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement Of Income And Comprehensive Income [Abstract]
NET INCOME	$ 117,827	$ 127,980	$ 391,650	$ 311,904
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX:
Currency translation adjustments (including a tax expense of $3 for the three months ended September 30, 2016 and $9 for the nine months ended September 30, 2016)	17,818	(1,828)	56,440	(10,106)
Employee benefit plans:
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)	(4,715)	(33)	(13,819)	(649)
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)	1,081	1,134	3,523	3,441
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX	14,184	(727)	46,144	(7,314)
COMPREHENSIVE INCOME	132,011	127,253	437,794	304,590
LESS - COMPREHENSIVE INCOME ATTRIBUTABLE TO NONCONTROLLING INTERESTS	2,261	82	5,661	4,989
COMPREHENSIVE INCOME ATTRIBUTABLE TO LAZARD GROUP LLC	$ 129,750	$ 127,171	$ 432,133	$ 299,601

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement Of Income And Comprehensive Income [Abstract]
Currency translation adjustments, tax expense		$ 3		$ 9
Tax benefit on actuarial loss, employee benefit plans	$ 1,197	17	$ 3,673	315
Tax expense, adjustment for items reclassified to earnings, employee benefit plans	$ 204	$ 375	$ 676	$ 1,171

Condensed Consolidated Stateme7

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 391,650	$ 311,904
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization of property	23,203	24,586
Amortization of deferred expenses and share-based incentive compensation	283,995	275,894
Amortization and other acquisition-related costs	1,946	1,720
Deferred tax provision (benefit)	2,413	(4,537)
(Increase) decrease in operating assets:
Deposits with banks and short-term investments	(171,734)	(135,152)
Cash deposited with clearing organizations and other segregated cash	(5,138)	115
Receivables-net	122,056	38,482
Investments	27,927	68,499
Other assets	(70,944)	(54,409)
Increase (decrease) in operating liabilities:
Deposits and other payables	164,784	32,186
Accrued compensation and benefits and other liabilities	(75,202)	(225,337)
Net cash provided by operating activities	694,956	333,951
CASH FLOWS FROM INVESTING ACTIVITIES:
Additions to property	(15,387)	(22,070)
Disposals of property	285	865
Net cash used in investing activities	(15,102)	(21,205)
Proceeds from:
Contributions from noncontrolling interests		93
Excess tax benefits from share-based incentive compensation		2,343
Other financing activities		30,518
Payments for:
Capital lease obligations	(7,329)	(1,234)
Distributions to noncontrolling interests	(3,049)	(966)
Purchase of Lazard Ltd Class A common stock	(252,538)	(228,865)
Distributions to members	(294,966)	(248,742)
Settlement of vested share-based incentive compensation	(67,384)	(55,562)
Other financing activities	(10,083)	(3,080)
Net cash used in financing activities	(635,349)	(505,495)
EFFECT OF EXCHANGE RATE CHANGES ON CASH	65,757	48
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	110,262	(192,701)
CASH AND CASH EQUIVALENTS—January 1	1,131,440	1,025,844
CASH AND CASH EQUIVALENTS—September 30	$ 1,241,702	$ 833,143

Condensed Consolidated Stateme8

Condensed Consolidated Statements of Changes in Members' Equity - USD ($) $ in Thousands		Total	Members' Equity [Member]	Accumulated Other Comprehensive Income (Loss), Net of Tax [Member]	Total Lazard Group LLC Members' Equity [Member]	Noncontrolling Interests [Member]
Balance at Dec. 31, 2015	[1]	$ 702,900	$ 839,517	$ (189,758)	$ 649,759	$ 53,141
Comprehensive income (loss):
Net income		311,904	306,915		306,915	4,989
Other comprehensive income (loss) - net of tax		(7,314)		(7,314)	(7,314)
Amortization of share-based incentive compensation		213,144	213,144		213,144
Distributions to members and noncontrolling interests, net		(249,615)	(248,742)		(248,742)	(873)
Purchase of Lazard Ltd Class A common stock		(228,865)	(228,865)		(228,865)
Delivery of Lazard Ltd Class A common stock in connection with share-based incentive compensation and related tax benefit		(55,422)	(55,422)		(55,422)
Business acquisitions and related equity transactions:
Delivery of Lazard Ltd Class A common stock and related tax benefit		2,984	2,984		2,984
Other		6,479	6,479		6,479
Balance at Sep. 30, 2016	[1]	696,195	836,010	(197,072)	638,938	57,257
Balance at Jun. 30, 2016				(196,346)
Comprehensive income (loss):
Net income		127,980
Other comprehensive income (loss) - net of tax		(727)		(726)
Balance at Sep. 30, 2016	[1]	696,195	836,010	(197,072)	638,938	57,257
Balance at Dec. 31, 2016	[2]	736,140	949,669	(270,775)	678,894	57,246
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		4,945	4,945		4,945
Balance, as adjusted at Dec. 31, 2016		741,085	954,614	(270,775)	683,839	57,246
Comprehensive income (loss):
Net income		391,650	385,990		385,990	5,660
Other comprehensive income (loss) - net of tax		46,144		46,143	46,143	1
Amortization of share-based incentive compensation		220,648	220,648		220,648
Distributions to members and noncontrolling interests, net		(298,015)	(294,966)		(294,966)	(3,049)
Purchase of Lazard Ltd Class A common stock		(252,538)	(252,538)		(252,538)
Delivery of Lazard Ltd Class A common stock in connection with share-based incentive compensation and related tax benefit		(67,384)	(67,384)		(67,384)
Business acquisitions and related equity transactions:
Lazard Ltd Class A common stock issuable (including related amortization)		278	278		278
Delivery of Lazard Ltd Class A common stock and related tax benefit		615	615		615
Other		(4,599)	(4,803)		(4,803)	204
Balance at Sep. 30, 2017	[2]	777,884	942,454	(224,632)	717,822	60,062
Balance at Jun. 30, 2017				(238,816)
Comprehensive income (loss):
Net income		117,827
Other comprehensive income (loss) - net of tax		14,184		14,184
Balance at Sep. 30, 2017	[2]	$ 777,884	$ 942,454	$ (224,632)	$ 717,822	$ 60,062
[1]	At both January 1, 2016 and September 30, 2016, in addition to profit participation interests, there were two managing member interests.
[2]	At both January 1, 2017 and September 30, 2017, in addition to profit participation interests, there were two managing member interests.

Condensed Consolidated Stateme9

Condensed Consolidated Statements of Changes in Members' Equity (Parenthetical) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Jan. 01, 2017	Jan. 01, 2016
Tax benefit related to delivery of Class A Common Stock in connection with share-based incentive compensation		$ 140
Tax benefit related to delivery of Class A Common Stock	$ 10	$ 144
Managing Member Interests [Member]
Membership Interests, shares issued	2	2	2	2

Organization and Basis of Prese

Organization and Basis of Presentation	9 Months Ended
	Sep. 30, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization and Basis of Presentation	1. ORGANIZATION AND BASIS OF PRESENTATION Organization The accompanying condensed consolidated financial statements are those of Lazard Group LLC and its subsidiaries (collectively referred to as “Lazard Group” or the “Company”). Lazard Group is a Delaware limited liability company and is governed by an Amended and Restated Operating Agreement dated as of October 26, 2015, as amended (the “Operating Agreement”). Lazard Ltd, a Bermuda holding company, and its subsidiaries (collectively referred to as “Lazard Ltd”), including its indirect investment in 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 September 30, 2017 and December 31, 2016. Lazard Ltd, through its control of the managing members of Lazard Group, controls Lazard Group. Lazard Group’s 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 accompanying condensed consolidated financial statements of Lazard Group have been prepared pursuant to the rules and regulations of the United States Securities and Exchange Commission (the “SEC”) regarding interim financial reporting. Accordingly, they do not include all of the information and notes required by accounting principles generally accepted in the United States of America (“U.S. GAAP”) for complete financial statements and should be read in conjunction with the audited consolidated financial statements and notes thereto included in Lazard Group’s Annual Report on Form 10-K for the year ended December 31, 2016. The accompanying December 31, 2016 unaudited condensed consolidated statement of financial condition data was derived from audited consolidated financial statements, but does not include all disclosures required by U.S. GAAP for annual financial statement purposes. The accompanying condensed consolidated financial statements reflect all adjustments which are, in the opinion of management, necessary for a fair presentation of the financial position, results of operations and cash flows for the interim periods presented. Preparing financial statements requires management to make estimates and assumptions that affect the amounts that are reported in the financial statements and the accompanying disclosures. For example, discretionary compensation and benefits expense for interim periods is accrued based on the year-to-date amount of revenue earned, and an assumed annual ratio of compensation and benefits expense to revenue, with the applicable amounts adjusted for certain items. Although these estimates are based on management’s knowledge of current events and actions that Lazard may undertake in the future, actual results may differ materially from the estimates. The consolidated results of operations for the three month and nine month periods ended September 30, 2017 are not indicative of the results to be expected for any future interim or annual period. The condensed consolidated financial statements include 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. 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. 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 condensed consolidated statements of financial condition.

Recent Accounting Developments

Recent Accounting Developments	9 Months Ended
	Sep. 30, 2017
New Accounting Pronouncements And Changes In Accounting Principles [Abstract]
Recent Accounting Developments	2. 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 new guidance is effective for annual and interim periods beginning after December 15, 2016. The Company adopted this new guidance on January 1, 2017. The new guidance has since January 1, 2017 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 condensed 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. Upon adoption of the new guidance, the Company also recorded deferred tax assets of $4,945, 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 14. 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 condensed 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 will adopt the revenue recognition guidance upon its effective date of January 1, 2018 and it intends to apply the modified cumulative effect approach upon transition. The Company’s implementation efforts include the identification of revenue within the scope of the guidance and the evaluation of revenue contracts. The Company continues to evaluate the potential impact of the new guidance including (i) the timing of revenue recognition for Financial Advisory fees and (ii) the presentation of certain contract costs. With respect to revenue recognition, the Company is assessing the potential impact of the new guidance on the Company’s recognition of certain M&A Advisory fees (e.g., transaction completion, transaction announcement and retainer fees), including whether the Company’s fulfillment of its performance obligations under M&A 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 issue continues to be deliberated by the Financial Reporting Executive Committee of the American Institute of Certified Public Accountants. With respect to the potential impact of the new guidance on the Company’s presentation of certain contract costs, the Company anticipates 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 identified to date 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 Company is currently evaluating the impact of this presentation. 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 early adoption is permitted. The new guidance is to be applied on a retrospective basis. The Company is currently evaluating the new guidance. 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 is currently evaluating the new guidance. Compensation — — — I n 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. 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. This new guidance is effective for annual and interim periods beginning after December 15, 2017, with early adoption permitted. The Company is currently evaluating the new guidance. 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, with early adoption permitted. The new guidance is to be applied on a prospective basis. 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

Receivables	9 Months Ended
	Sep. 30, 2017
Receivables [Abstract]
Receivables	3. RECEIVABLES The Company’s receivables represent fee receivables, amounts due from customers and other receivables, and amounts due from Lazard Ltd subsidiaries. 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 three month and nine month periods ended September 30, 2017 and 2016 was as follows: Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 Beginning Balance $ 25,094 $ 13,569 $ 16,386 $ 12,882 Bad debt expense, net of recoveries 4,753 1,545 18,584 4,124 Charge-offs, foreign currency translation and other adjustments (2,383 ) (2,147 ) (7,506 ) (4,039 ) Ending Balance $ 27,464 $ 12,967 $ 27,464 $ 12,967 Bad debt expense, net of recoveries is included in “investment banking and other advisory fees” on the condensed consolidated statements of operations. At September 30, 2017 and December 31, 2016, the Company had receivables past due or deemed uncollectible of $44,372 and $22,212, respectively. Of the Company’s fee receivables at September 30, 2017 and December 31, 2016, $64,965 and $76,133, respectively, represented interest-bearing financing receivables. In addition, at September 30, 2017 and December 31, 2016, the Company had interest-bearing receivables from Lazard Ltd subsidiaries of $3,742 and $20,365, respectively. 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 $502,312 and $570,486 at September 30, 2017 and December 31, 2016, respectively, approximates fair value.

Investments

Investments	9 Months Ended
	Sep. 30, 2017
Investments Schedule [Abstract]
Investments	4. INVESTMENTS The Company’s investments and securities sold, not yet purchased, consist of the following at September 30, 2017 and December 31, 2016: September 30, December 31, 2017 2016 Interest-bearing deposits $ 552 $ 456 Debt 6 - Equities 46,181 41,017 Funds: Alternative investments (a) 23,518 32,441 Debt (a) 86,900 74,597 Equity (a) 191,193 188,268 Private equity 78,376 122,421 379,987 417,727 Equity method 222 222 Total investments 426,948 459,422 Less: Interest-bearing deposits 552 456 Equity method 222 222 Investments, at fair value $ 426,174 $ 458,744 Securities sold, not yet purchased, at fair value (included in “other liabilities”) $ 5,921 $ 4,482 (a) Interests in alternative investment funds, debt funds and equity funds include investments with fair values of $13,850, $48,451 and $124,570, respectively, at September 30, 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 Lazard Fund Interests (“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 6 and 12). 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. 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 three month and nine month periods ended September 30, 2017 and 2016, the Company reported in “revenue-other” on its condensed consolidated statements of operations net unrealized investment gains and losses pertaining to “trading” securities still held as of the reporting date as follows: Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 Net unrealized investment gains $ 6,949 $ 9,975 $ 27,932 $ 15,221

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	5. 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 estimated 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. 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 6. 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 September 30, 2017 and December 31, 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: September 30, 2017 Level 1 Level 2 Level 3 NAV Total Assets: Investments: Debt $ 6 $ - $ - $ - $ 6 Equities 44,634 - 1,547 - 46,181 Funds: Alternative investments 15,798 - - 7,720 23,518 Debt 86,894 - - 6 86,900 Equity 191,144 - - 49 191,193 Private equity - - - 78,376 78,376 Derivatives - 3,443 - - 3,443 Total $ 338,476 $ 3,443 $ 1,547 $ 86,151 $ 429,617 Liabilities: Securities sold, not yet purchased $ 5,921 $ - $ - $ - $ 5,921 Contingent consideration liability - - 4,010 - 4,010 Derivatives - 189,142 - - 189,142 Total $ 5,921 $ 189,142 $ 4,010 $ - $ 199,073 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 - - 3,364 - 3,364 Derivatives - 182,223 - - 182,223 Total $ 4,482 $ 182,223 $ 3,364 $ - $ 190,069 The following tables provide a summary of changes in fair value of the Company’s Level 3 assets and liabilities for the three month and nine month periods ended September 30, 2017 and 2016: Three Months Ended September 30, 2017 Beginning Balance Net Realized Gains/Losses Included In Earnings (a) Purchases/ Acquisitions Sales/ Dispositions Foreign Currency Translation Adjustments Ending Balance Assets: Investments: Equities $ 3,072 $ 130 $ - $ (1,661 ) $ 6 $ 1,547 Total Level 3 Assets $ 3,072 $ 130 $ - $ (1,661 ) $ 6 $ 1,547 Liabilities: Contingent consideration liability $ 4,108 $ (98 ) $ - $ - $ - $ 4,010 Total Level 3 Liabilities $ 4,108 $ (98 ) $ - $ - $ - $ 4,010 Nine Months Ended September 30, 2017 Beginning Balance Net Realized Gains/Losses Included In Earnings (a) Purchases/ Acquisitions Sales/ Dispositions Foreign Currency Translation Adjustments Ending Balance Assets: Investments: Equities $ 1,508 $ 4 $ 1,661 $ (1,669 ) $ 43 $ 1,547 Total Level 3 Assets $ 1,508 $ 4 $ 1,661 $ (1,669 ) $ 43 $ 1,547 Liabilities: Contingent consideration liability $ 3,364 $ 646 $ - $ - $ - $ 4,010 Total Level 3 Liabilities $ 3,364 $ 646 $ - $ - $ - $ 4,010 Three Months Ended September 30, 2016 Beginning Balance Net Realized Gains / Included In Earnings (a) Purchases/ Acquisitions Sales/ Dispositions Foreign Currency Translation Adjustments Ending Balance Assets: Investments: Equities $ 1,298 $ 2 $ - $ - $ 21 $ 1,321 Total Level 3 Assets $ 1,298 $ 2 $ - $ - $ 21 $ 1,321 Nine Months Ended September 30, 2016 Beginning Balance Net Realized Gains/Losses Included In Earnings (a) Purchases/ Acquisitions Sales/ Dispositions Foreign Currency Translation Adjustments Ending Balance Assets: Investments: Equities $ 1,276 $ 12 $ - $ - $ 33 $ 1,321 Total Level 3 Assets $ 1,276 $ 12 $ - $ - $ 33 $ 1,321 (a) Earnings recorded in “other revenue” for investments in equities for the three month and nine month periods ended September 30, 2017 and the three month and nine month periods ended September 30, 2016 include net unrealized gains of $130, $2, $2 and $7, respectively. Earnings recorded in “amortization and other acquisition-related costs” for the contingent consideration liability for the three month and nine month periods ended September 30, 2017 include unrealized gains (losses) of $98 and $(646), respectively. There were no transfers between any of the Level 1, 2 and 3 categories in the fair value measurement hierarchy during the three month and nine month periods ended September 30, 2017 and 2016. Certain investments that were valued at NAV as of December 31, 2016 were transferred to Level 2 from the NAV category in the six months ended June 30, 2017, as these investments were valued based on a probable transaction value as of the reporting date that differs from NAV. Such investments were sold in the second quarter of 2017. The following tables present, at September 30, 2017 and December 31, 2016, certain investments that are valued using NAV or its equivalent as a practical expedient in determining fair value: September 30, 2017 Estimated Liquidation Period of Investments Not Redeemable Investments Redeemable Fair Value Unfunded Commitments % of Fair Value Not Redeemable % Next 5 Years % 5-10 Years % Thereafter Redemption Frequency Redemption Notice Period Alternative Hedge funds $ 6,617 $ - NA NA NA NA (a) <30-60 days Funds of funds 517 - NA NA NA NA (b) <30-90 days Other 586 - NA NA NA NA (c) <30-60 days Debt funds 6 - NA NA NA NA (d) 30 days Equity funds 49 - NA NA NA NA (e) <30-90 days Private equity funds: Equity growth 78,376 10,085 (f) 100 % 16 % 39 % 45 % NA NA Total $ 86,151 $ 10,085 (a) weekly (51%), monthly (2%) and quarterly (47%) (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 $5,915 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 % Next 5 Years % 5-10 Years % Thereafter Redemption Frequency Redemption Notice Period Alternative Hedge funds $ 6,190 $ - NA NA NA NA (a) <30-60 days Funds of funds 492 - NA NA NA NA (b) <30-90 days Other 443 - NA NA NA NA (c) <30-60 days Debt funds 6 - NA NA NA NA (d) 30 days Equity funds 39 - NA NA NA NA (e) <30-90 days Private equity funds: Equity growth 90,824 9,183 (f) 100 % 12 % 33 % 55 % NA NA Mezzanine debt 31,597 - 100 % - - 100 % NA NA 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 September 30, 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

Derivatives	9 Months Ended
	Sep. 30, 2017
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Derivatives	6. DERIVATIVES 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 condensed 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 condensed consolidated statements of operations. In addition to the derivative instruments described above, the Company records derivative liabilities relating to its obligations pertaining to 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 condensed consolidated statements of financial condition. Changes in the fair value of the derivative liabilities are included in “compensation and benefits” in the condensed 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 condensed consolidated statements of operations. 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 12) on the accompanying condensed consolidated statements of financial condition as of September 30, 2017 and December 31, 2016: September 30, December 31, 2017 2016 Derivative Assets: Forward foreign currency exchange rate contracts $ 2,938 $ 1,993 Total return swaps and other (a) 505 - $ 3,443 $ 1,993 Derivative Liabilities: Forward foreign currency exchange rate contracts $ 3,835 $ 2,792 Total return swaps and other (a) 9,557 9,043 LFI and other similar deferred compensation arrangements 175,750 170,388 $ 189,142 $ 182,223 (a) For total return swaps, amounts represent the netting of gross derivative assets and liabilities of $509 and $9,561 as of September 30, 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 $17,496 and $16,996 as of September 30, 2017 and December 31, 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 condensed consolidated statements of operations for the three month and nine month periods ended September 30, 2017 and 2016, were as follows: Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 Forward foreign currency exchange rate contracts $ (2,991 ) $ (1,591 ) $ (8,149 ) $ (8,445 ) LFI and other similar deferred compensation arrangements (4,875 ) (6,909 ) (17,981 ) (4,707 ) Total return swaps and other (3,890 ) (3,674 ) (12,872 ) (3,880 ) Total $ (11,756 ) $ (12,174 ) $ (39,002 ) $ (17,032 )

Property

Property	9 Months Ended
	Sep. 30, 2017
Property Plant And Equipment [Abstract]
Property	7. PROPERTY At September 30, 2017 and December 31, 2016, property consisted of the following: Estimated Depreciable September 30, December 31, Life in Years 2017 2016 Buildings 33 $ 149,548 $ 132,821 Leasehold improvements 3-20 174,129 175,810 Furniture and equipment 3-10 179,890 172,325 Construction in progress 11,843 14,038 Total 515,410 494,994 Less - Accumulated depreciation and amortization 314,708 285,997 Property $ 200,702 $ 208,997

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	9 Months Ended
	Sep. 30, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	8. GOODWILL AND OTHER INTANGIBLE ASSETS The components of goodwill and other intangible assets at September 30, 2017 and December 31, 2016 are presented below: September 30, December 31, 2017 2016 Goodwill $ 362,773 $ 352,124 Other intangible assets (net of accumulated amortization) 5,558 6,858 $ 368,331 $ 358,982 At September 30, 2017 and December 31, 2016, goodwill of $298,232 and $287,583, 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 nine month periods ended September 30, 2017 and 2016 are as follows: Nine Months Ended September 30, 2017 2016 Balance, January 1 $ 352,124 $ 320,761 Foreign currency translation adjustments 10,649 4,906 Balance, September 30 $ 362,773 $ 325,667 All changes in the carrying amount of goodwill for the nine month periods ended September 30, 2017 and 2016 are attributable to the Company’s Financial Advisory segment. The gross cost and accumulated amortization of other intangible assets as of September 30, 2017 and December 31, 2016, by major intangible asset category, are as follows: September 30, 2017 December 31, 2016 Gross Cost Accumulated Amortization Net Carrying Amount Gross Cost Accumulated Amortization Net Carrying Amount Success/performance fees $ 33,040 $ 27,693 $ 5,347 $ 33,040 $ 26,543 $ 6,497 Management fees, customer relationships and non-compete agreements 33,436 33,225 211 33,436 33,075 361 $ 66,476 $ 60,918 $ 5,558 $ 66,476 $ 59,618 $ 6,858 Amortization expense of intangible assets, included in “amortization and other acquisition-related costs” in the condensed consolidated statements of operations, for the three month and nine month periods ended September 30, 2017 was $433 and $1,300, respectively, and for the three month and nine month periods ended September 30, 2016 was $746 and $1,720, respectively. Estimated future amortization expense is as follows: Year Ending December 31, Amortization Expense (a) 2017 (October 1 through December 31) $ 284 2018 5,274 Total amortization expense $ 5,558 (a) Approximately 38% of intangible asset amortization is attributable to a noncontrolling interest.

Senior Debt

Senior Debt	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Senior Debt	9. SENIOR DEBT Senior debt is comprised of the following as of September 30, 2017 and December 31, 2016: Outstanding as of Initial Annual September 30, 2017 December 31, 2016 Principal Amount Maturity Date Interest Rate(a) 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 $ 2,878 $ 497,122 $ 500,000 $ 3,569 $ 496,431 Lazard Group 2025 Senior Notes 400,000 2/13/25 3.75 % 400,000 3,479 396,521 400,000 3,833 396,167 Lazard Group 2027 Senior Notes 300,000 3/1/27 3.625 % 300,000 3,707 296,293 300,000 3,998 296,002 Total $ 1,200,000 $ 10,064 $ 1,189,936 $ 1,200,000 $ 11,400 $ 1,188,600 (a) The effective interest rates of Lazard Group’s 4.25% senior notes due November 14, 2020 (the “2020 Notes”), Lazard Group’s 3.75% senior notes due February 13, 2025 (the “2025 Notes”) and Lazard Group’s 3.625% senior notes due March 1, 2027 (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 September 30, 2017 and December 31, 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 September 30, 2017, the Company was in compliance with such provisions. All of the Company’s senior debt obligations are unsecured. As of September 30, 2017, the Company had approximately $175,000 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 $24,000 (at September 30, 2017 exchange rates). The Company’s senior debt at September 30, 2017 and December 31, 2016 is carried at historical amounts of $1,189,936 and $1,188,600, respectively. At those dates, the fair value of such senior debt was approximately $1,230,000 and $1,204,000, respectively. The fair value of the Company’s senior debt is based on market quotations. The Company’s senior debt would be categorized within Level 2 of the hierarchy of fair value measurements if carried at fair value.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2017
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	10. COMMITMENTS AND CONTINGENCIES Leases —The Company has various leases and other contractual commitments arising in the ordinary course of business. 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 September 30, 2017, LFB had $2,948 of such indemnifications and held $2,948 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 condensed consolidated statement of financial condition. Business Acquisitions —For a business acquired in 2016, consideration consists of (i) previously paid one-time cash payment and 60,817 shares of Class A common stock subject to non-compete provisions and (ii) up to 210,431 additional shares of Class A common stock that are subject to certain performance thresholds. As of September 30, 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 September 30, 2017, LFB and LFNY had no such underwriting commitments. See Notes 5 and 13 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 condensed 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.

Members' Equity

Members' Equity	9 Months Ended
	Sep. 30, 2017
Equity [Abstract]
Members' Equity	11. MEMBERS’ EQUITY Lazard Group Distributions —Distributions in respect of Lazard Group’s common membership interests are allocated to the holders of such interests in accordance with the provisions of the Operating Agreement. Such distributions primarily represent amounts necessary to fund (i) any dividends Lazard Ltd may declare on its Class A common stock and (ii) tax distributions in respect of income taxes that Lazard Ltd’s subsidiaries incur. During the nine month periods ended September 30, 2017 and 2016, Lazard Group distributed $294,966 and $248,742, respectively, to the subsidiaries of Lazard Ltd. Pursuant to Lazard Group’s Operating Agreement, Lazard Group allocates and distributes to its members a substantial portion of its distributable profits in installments as soon as practicable after the end of each fiscal year. Such installment distributions usually begin in February. Share Repurchase Program —During the nine month period ended September 30, 2017 and since 2014, the Board of Directors of Lazard authorized the repurchase of Lazard Ltd Class A common stock as set forth in the table below: Date Repurchase Authorization Expiration April 2014 $ 200,000 December February 2015 $ 150,000 December January 2016 $ 200,000 December April 2016 $ 113,182 December November 2016 $ 236,000 December 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 quarter to quarter due to a variety of factors. Purchases with respect to such program are set forth in the table below: Nine Months Ended September 30: Number of Shares Purchased Average Price Per Share 2016 6,656,250 $ 34.38 2017 5,838,520 $ 43.25 During the nine month periods ended September 30, 2017 and 2016, certain of our executive officers received Lazard Ltd 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 Lazard Ltd 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 nine month periods ended September 30, 2017 and 2016, the Company purchased shares of Lazard Ltd Class A common stock from an executive officer. The aggregate value of all such purchases during the nine month periods ended September 30, 2017 and 2016 was approximately $14,700 and $4,900, respectively. As of September 30, 2017, a total of $102,587 of share repurchase authorization remained available under Lazard Ltd’s share repurchase program, which will expire on December 31, 2018. In addition, on October 25, 2017, the Board of Directors of Lazard authorized the repurchase of up to $200,000 of additional shares of Lazard Ltd’s Class A common stock, which authorization will expire on December 31, 2019. During the nine month period ended September 30, 2017, Lazard Ltd 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. Accumulated Other Comprehensive Income (Loss), Net of Tax (“AOCI”) —The tables below reflect the balances of each component of AOCI at September 30, 2017 and 2016 and activity during the three month and nine month periods then ended: Three Months Ended September 30, 2017 Currency Translation Adjustments Employee Benefit Plans Total AOCI Amount Attributable to Noncontrolling Interests Total Lazard Group AOCI Balance, July 1, 2017 $ (70,684 ) $ (168,133 ) $ (238,817 ) $ (1 ) $ (238,816 ) Activity: Other comprehensive income (loss) before reclassifications 17,818 (4,715 ) 13,103 - 13,103 Adjustments for items reclassified to earnings, net of tax - 1,081 1,081 - 1,081 Net other comprehensive income (loss) 17,818 (3,634 ) 14,184 - 14,184 Balance, September 30, 2017 $ (52,866 ) $ (171,767 ) $ (224,633 ) $ (1 ) $ (224,632 ) Nine Months Ended September 30, 2017 Currency Translation Adjustments Employee Benefit Plans Total AOCI Amount Attributable to Noncontrolling Interests Total Lazard Group AOCI Balance, January 1, 2017 $ (109,306 ) $ (161,471 ) $ (270,777 ) $ (2 ) $ (270,775 ) Activity: Other comprehensive income (loss) before reclassifications 56,440 (13,819 ) 42,621 1 42,620 Adjustments for items reclassified to earnings, net of tax - 3,523 3,523 3,523 Net other comprehensive income (loss) 56,440 (10,296 ) 46,144 1 46,143 Balance, September 30, 2017 $ (52,866 ) $ (171,767 ) $ (224,633 ) $ (1 ) $ (224,632 ) Three Months Ended September 30, 2016 Currency Translation Adjustments Employee Benefit Plans Total AOCI Amount Attributable to Noncontrolling Interests Total Lazard Group AOCI Balance, July 1, 2016 $ (60,965 ) $ (135,382 ) $ (196,347 ) $ (1 ) $ (196,346 ) Activity: Other comprehensive loss before reclassifications (1,828 ) (33 ) (1,861 ) (1 ) (1,860 ) Adjustments for items reclassified to earnings, net of tax - 1,134 1,134 - 1,134 Net other comprehensive income (loss) (1,828 ) 1,101 (727 ) (1 ) (726 ) Balance, September 30, 2016 $ (62,793 ) $ (134,281 ) $ (197,074 ) $ (2 ) $ (197,072 ) Nine Months Ended September 30, 2016 Currency Translation Adjustments Employee Benefit Plans Total AOCI Amount Attributable to Noncontrolling Interests Total Lazard Group AOCI Balance, January 1, 2016 $ (52,687 ) $ (137,073 ) $ (189,760 ) $ (2 ) $ (189,758 ) Activity: Other comprehensive loss before reclassifications (10,106 ) (649 ) (10,755 ) - (10,755 ) Adjustments for items reclassified to earnings, net of tax - 3,441 3,441 - 3,441 Net other comprehensive income (loss) (10,106 ) 2,792 (7,314 ) - (7,314 ) Balance, September 30, 2016 $ (62,793 ) $ (134,281 ) $ (197,074 ) $ (2 ) $ (197,072 ) The table below reflects adjustments for items reclassified out of AOCI, by component, for the three month and nine month periods ended September 30, 2017 and 2016: Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 Amortization relating to employee benefit plans (a) $ 1,285 $ 1,509 $ 4,199 $ 4,612 Less - related income taxes 204 375 676 1,171 Total reclassifications, net of tax $ 1,081 $ 1,134 $ 3,523 $ 3,441 (a) Included in the computation of net periodic benefit cost (see Note 13). Such amounts are included in “compensation and benefits” expense on the condensed 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 three month and nine month periods ended September 30, 2017 and 2016 and noncontrolling interests as of September 30, 2017 and December 31, 2016 in the Company’s condensed consolidated financial statements: Net Income Attributable to Noncontrolling Interests Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 Edgewater $ 2,260 $ 81 $ 5,657 $ 4,988 Other 1 2 3 1 Total $ 2,261 $ 83 $ 5,660 $ 4,989 Noncontrolling Interests as of September 30, December 31, 2017 2016 Edgewater $ 60,050 $ 57,238 Other 12 8 Total $ 60,062 $ 57,246

Incentive Plans

Incentive Plans	9 Months Ended
	Sep. 30, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Incentive Plans	12. 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 three month and nine month periods ended September 30, 2017 and 2016 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 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 condensed consolidated statements of operations for the three month and nine month periods ended September 30, 2017 and 2016: Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 Share-based incentive awards: RSUs $ 39,898 $ 39,447 $ 150,193 $ 134,419 PRSUs 9,896 11,252 38,095 38,276 Restricted Stock 7,697 7,015 30,507 38,833 DSUs 78 53 926 808 Total $ 57,569 $ 57,767 $ 219,721 $ 212,336 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 previously recorded 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. 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 nine month periods ended September 30, 2017 and 2016, dividend participation rights required the issuance of 866,914 and 969,054 RSUs, respectively. Non-executive members of the Board of Directors of Lazard Group, who are the same Non-Executive Directors of Lazard Ltd (“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 and 38,771 DSUs granted during the nine month periods ended September 30, 2017 and 2016, 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. 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 nine month periods ended September 30, 2017 and 2016, 10,541 and 7,407 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 nine month periods ended September 30, 2017 and 2016: RSUs DSUs Units Weighted Average Grant Date Fair Value Units Weighted Average Grant Date Fair Value Balance, January 1, 2017 11,698,138 $ 40.65 276,725 $ 36.05 Granted (including 866,914 RSUs relating to dividend participation) 5,294,156 $ 43.01 41,821 $ 44.30 Forfeited (162,320 ) $ 39.97 - - Vested (3,977,477 ) $ 45.27 (43,465 ) $ 35.77 Balance, September 30, 2017 12,852,497 $ 40.20 275,081 $ 37.35 Balance, January 1, 2016 9,599,658 $ 44.06 312,670 $ 35.98 Granted (including 969,054 RSUs relating to dividend participation) 6,649,625 $ 34.64 46,178 $ 34.98 Forfeited (181,337 ) $ 39.79 - - Vested (4,527,559 ) $ 39.16 (84,759 ) $ 35.30 Balance, September 30, 2016 11,540,387 $ 40.62 274,089 $ 36.02 In connection with RSUs that vested during the nine month periods ended September 30, 2017 and 2016, the Company satisfied its minimum statutory tax withholding requirements in lieu of delivering 1,282,843 and 1,416,643 shares of Class A common stock during such respective nine month periods. Accordingly, 2,694,634 and 3,110,916 shares of Class A common stock held by the Company were delivered during the nine month periods ended September 30, 2017 and 2016, respectively. As of September 30, 2017, estimated unrecognized RSU compensation expense was approximately $178,321, with such expense expected to be recognized over a weighted average period of approximately 0.9 years subsequent to September 30, 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 nine month periods ended September 30, 2017 and 2016: Restricted Shares Weighted Average Grant Date Fair Value Balance, January 1, 2017 1,655,073 $ 40.95 Granted 841,355 $ 42.58 Forfeited (65,086 ) $ 40.80 Vested (483,811 ) $ 45.42 Balance, September 30, 2017 1,947,531 $ 40.54 Balance, January 1, 2016 713,738 $ 47.12 Granted 1,795,258 $ 36.74 Forfeited (33,943 ) $ 40.49 Vested (802,276 ) $ 37.09 Balance, September 30, 2016 1,672,777 $ 40.92 In connection with shares of restricted Class A common stock that vested during the nine month periods ended September 30, 2017 and 2016, the Company satisfied its minimum statutory tax withholding requirements in lieu of delivering 147,775 and 132,984 shares of Class A common stock during such respective nine month periods. Accordingly, 336,036 and 669,292 shares of Class A common stock held by the Company were delivered during the nine month periods ended September 30, 2017 and 2016, 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 September 30, 2017, estimated unrecognized restricted stock expense was approximately $35,369, with such expense to be recognized over a weighted average period of approximately 0.8 years subsequent to September 30, 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 Lazard Ltd’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 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 Lazard Ltd 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 nine month periods ended September 30, 2017 and 2016: PRSUs Weighted Average Grant Date Fair Value Balance, January 1, 2017 1,590,756 $ 40.76 Granted (a) 458,113 $ 43.76 Vested (825,565 ) $ 42.27 Balance, September 30, 2017 1,223,304 $ 40.86 Balance, January 1, 2016 1,019,038 $ 44.49 Granted (a) 627,956 $ 32.91 Vested (417,021 ) $ 38.43 Balance, September 30, 2016 1,229,973 $ 40.63 (a) Represents PRSU awards granted during the relevant year at the target payout level. In connection with certain PRSUs that vested or were settled during the nine month periods ended September 30, 2017 and 2016, the Company satisfied its minimum statutory tax withholding requirements in lieu of delivering 127,530 and 64,169 shares of Class A common stock during such respective nine month periods. Accordingly, 698,035 and 352,852 shares of Class A common stock held by the Company were delivered during the nine month periods ended September 30, 2017 and 2016, 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 September 30, 2017, the total estimated unrecognized compensation expense was approximately $11,846, and the Company expects to amortize such expense over a weighted-average period of approximately 0.8 years subsequent to September 30, 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 condensed 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 nine month periods ended September 30, 2017 and 2016: Prepaid Compensation Asset Compensation Liability Balance, January 1, 2017 $ 49,650 $ 170,388 Granted 77,580 77,580 Settled - (95,718 ) Forfeited (866 ) (1,647 ) Amortization (52,702 ) - Change in fair value related to: Increase in fair value of underlying investments - 17,981 Adjustment for estimated forfeitures - 5,333 Other 1,515 1,833 Balance, September 30, 2017 $ 75,177 $ 175,750 Prepaid Compensation Asset Compensation Liability Balance, January 1, 2016 $ 75,703 $ 193,574 Granted 51,871 51,871 Settled - (75,583 ) Forfeited (1,967 ) (3,435 ) Amortization (56,784 ) - Change in fair value related to: Increase in fair value of underlying investments - 4,707 Adjustment for estimated forfeitures - 3,551 Other (1,232 ) 585 Balance, September 30, 2016 $ 67,591 $ 175,270 The amortization of the prepaid compensation asset will generally be recognized over a weighted average period of approximately 0.9 years subsequent to September 30, 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 condensed consolidated statements of operations for the three month and nine month periods ended September 30, 2017 and 2016: Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 Amortization, net of forfeitures $ 15,961 $ 18,116 $ 57,254 $ 58,867 Change in the fair value of underlying investments 4,875 6,909 17,981 4,707 Total $ 20,836 $ 25,025 $ 75,235 $ 63,574

Employee Benefit Plans

Employee Benefit Plans	9 Months Ended
	Sep. 30, 2017
Compensation And Retirement Disclosure [Abstract]
Employee Benefit Plans	13. 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 condensed consolidated statements of operations. 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 following table summarizes the components of net periodic benefit cost (credit) related to the Company’s post-retirement plans for the three month and nine month periods ended September 30, 2017 and 2016: Pension Plans Medical Plan Three Months Ended September 30, 2017 2016 2017 2016 Components of Net Periodic Benefit Cost (Credit): Service cost $ 373 $ 313 $ - $ 3 Interest cost 4,191 4,833 - 42 Expected return on plan assets (6,295 ) (6,648 ) - - Amortization of: Prior service cost - 599 - - Net actuarial loss (gain) 1,285 957 - (47 ) Net periodic benefit cost (credit) $ (446 ) $ 54 $ - $ (2 ) Pension Plans Medical Plan Nine Months Ended September 30, 2017 2016 2017 2016 Components of Net Periodic Benefit Cost (Credit): Service cost $ 1,048 $ 934 $ - $ 9 Interest cost 12,258 15,292 - 125 Expected return on plan assets (18,855 ) (21,047 ) - - Amortization of: Prior service cost 30 1,793 - - Net actuarial loss (gain) 4,169 2,958 - (139 ) Net periodic benefit cost (credit) $ (1,350 ) $ (70 ) $ - $ (5 )

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Income Taxes	14. INCOME TAXES Although a portion of Lazard Group’s income is subject to U.S. federal income taxes, Lazard Group primarily operates in the U.S. as a limited liability company that is treated as a partnership for U.S. federal income tax purposes. As a result, Lazard Group’s income from its U.S. operations is generally not subject to U.S. federal income taxes because such income is attributable to its partners. Lazard Group, 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 New York City Unincorporated Business Tax (“UBT”) attributable to its operations apportioned to New York City. The Company recorded income tax provisions of $27,367 and $81,802 for the three month and nine month periods ended September 30, 2017, respectively, and $21,653 and $49,110 for the three month and nine month periods ended September 30, 2016, respectively, representing effective tax rates of 18.8%, 17.3%, 14.5% and 13.6%, respectively. The difference between the U.S. federal statutory rate of 35.0% and the effective tax rates reflected above principally relates to (i) Lazard Group primarily operating as a limited liability company in the U.S., (ii) change in the valuation allowance affecting the provision for income taxes, (iii) taxes payable to foreign jurisdictions, (iv) excess net tax benefit for share-based incentive compensation, and (v) U.S. state and local taxes, which are incremental to the U.S. federal statutory tax rate. 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 $2,047 from the vesting of share-based incentive compensation in the provision for income taxes in the condensed consolidated statements of operations for the nine month period ended September 30, 2017. The Company also recorded deferred tax assets of $4,945, 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 2 for further information on the adoption of this new guidance. Substantially all of Lazard’s operations outside the U.S. are conducted in “pass-through” entities for U.S. income tax purposes. The Company provides for U.S. income taxes on a current basis for the relevant portion of those earnings. The repatriation of prior earnings attributable to “non-pass-through” entities would not result in the recognition of a material amount of additional U.S. income taxes.

Related Parties

Related Parties	9 Months Ended
	Sep. 30, 2017
Related Party Transactions [Abstract]
Related Parties	15. RELATED PARTIES Receivable from and Payable to Lazard Ltd Subsidiaries Lazard Group’s receivables from subsidiaries of Lazard Ltd at September 30, 2017 and December 31, 2016 included interest- bearing loans of $3,742 and $20,365, respectively, including accrued interest thereon. Interest income relating to interest-bearing loans with subsidiaries of Lazard Ltd amounted to $5 and $148 for the three month and nine month periods ended September 30, 2017, respectively, and $23 and $233 for the three month and nine month periods ended September 30, 2016, respectively. Lazard Group’s payables to subsidiaries of Lazard Ltd at September 30, 2017 and December 31, 2016 included interest-bearing loans, including interest thereon, of $63,726 and $60,500, respectively. Interest expense relating to interest-bearing loans with subsidiaries of Lazard Ltd amounted to $976 and $2,851 for the three month and nine month periods ended September 30, 2017, respectively, and $875 and $2,604 for the three month and nine month periods ended September 30, 2016, respectively. 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 fees for providing such services. Investment advisory fees relating to such services were $163,767 and $471,727 for the three month and nine month periods ended September 30, 2017, respectively, and $130,546 and $374,250 for the three month and nine month periods ended September 30, 2016, respectively, and are included in “asset management fees” on the condensed consolidated statements of operations. Of such amounts, $57,156 and $49,944 remained as receivables at September 30, 2017 and December 31, 2016, respectively, and are included in “fees receivable” on the condensed consolidated statements of financial condition. Other See Note 11 for information regarding related party transactions pertaining to shares repurchased from certain of our executive officers.

Regulatory Authorities

Regulatory Authorities	9 Months Ended
	Sep. 30, 2017
Regulatory Capital Requirements [Abstract]
Regulatory Authorities	16. 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 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 September 30, 2017, the aggregate regulatory net capital of the U.K. Subsidiaries was $190,884, which exceeded the minimum requirement by $172,104. 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 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 (asset management), also are subject to regulation and supervision by the Autorité des Marchés Financiers. At September 30, 2017, the consolidated regulatory net capital of CFLF was $137,988, which exceeded the minimum requirement set for regulatory capital levels by $89,582. 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. In 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 June 30, 2017, the regulatory net capital of the combined European regulated group was $167,325, which exceeded the minimum requirement set for regulatory capital levels by $81,079. 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 September 30, 2017, for those subsidiaries with regulatory capital requirements, their aggregate net capital was $151,460, which exceeded the minimum required capital by $124,535. At September 30, 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

Segment Information	9 Months Ended
	Sep. 30, 2017
Segment Reporting [Abstract]
Segment Information	17. 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 three month and nine month periods ended September 30, 2017 and 2016 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. 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: Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 Financial Advisory Net Revenue $ 305,890 $ 343,488 $ 1,052,206 $ 896,467 Operating Expenses 243,421 257,561 814,068 718,366 Operating Income $ 62,469 $ 85,927 $ 238,138 $ 178,101 Asset Management Net Revenue $ 320,487 $ 267,725 $ 913,728 $ 767,610 Operating Expenses 217,233 185,753 621,885 543,616 Operating Income $ 103,254 $ 81,972 $ 291,843 $ 223,994 Corporate Net Revenue $ (2,606 ) $ (3,336 ) $ (3,660 ) $ (24,885 ) Operating Expenses 17,923 14,930 52,869 16,196 Operating Loss $ (20,529 ) $ (18,266 ) $ (56,529 ) $ (41,081 ) Total Net Revenue $ 623,771 $ 607,877 $ 1,962,274 $ 1,639,192 Operating Expenses 478,577 458,244 1,488,822 1,278,178 Operating Income $ 145,194 $ 149,633 $ 473,452 $ 361,014 As Of September 30, 2017 December 31, 2016 Total Assets Financial Advisory $ 808,564 $ 883,384 Asset Management 668,410 645,653 Corporate 2,299,126 1,986,947 Total $ 3,776,100 $ 3,515,984

Organization and Basis of Pre27

Organization and Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization	Organization The accompanying condensed consolidated financial statements are those of Lazard Group LLC and its subsidiaries (collectively referred to as “Lazard Group” or the “Company”). Lazard Group is a Delaware limited liability company and is governed by an Amended and Restated Operating Agreement dated as of October 26, 2015, as amended (the “Operating Agreement”). Lazard Ltd, a Bermuda holding company, and its subsidiaries (collectively referred to as “Lazard Ltd”), including its indirect investment in 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 September 30, 2017 and December 31, 2016. Lazard Ltd, through its control of the managing members of Lazard Group, controls Lazard Group. Lazard Group’s 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	Basis of Presentation The accompanying condensed consolidated financial statements of Lazard Group have been prepared pursuant to the rules and regulations of the United States Securities and Exchange Commission (the “SEC”) regarding interim financial reporting. Accordingly, they do not include all of the information and notes required by accounting principles generally accepted in the United States of America (“U.S. GAAP”) for complete financial statements and should be read in conjunction with the audited consolidated financial statements and notes thereto included in Lazard Group’s Annual Report on Form 10-K for the year ended December 31, 2016. The accompanying December 31, 2016 unaudited condensed consolidated statement of financial condition data was derived from audited consolidated financial statements, but does not include all disclosures required by U.S. GAAP for annual financial statement purposes. The accompanying condensed consolidated financial statements reflect all adjustments which are, in the opinion of management, necessary for a fair presentation of the financial position, results of operations and cash flows for the interim periods presented. Preparing financial statements requires management to make estimates and assumptions that affect the amounts that are reported in the financial statements and the accompanying disclosures. For example, discretionary compensation and benefits expense for interim periods is accrued based on the year-to-date amount of revenue earned, and an assumed annual ratio of compensation and benefits expense to revenue, with the applicable amounts adjusted for certain items. Although these estimates are based on management’s knowledge of current events and actions that Lazard may undertake in the future, actual results may differ materially from the estimates. The consolidated results of operations for the three month and nine month periods ended September 30, 2017 are not indicative of the results to be expected for any future interim or annual period. The condensed consolidated financial statements include 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. 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. 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 condensed consolidated statements of financial condition.
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 new guidance is effective for annual and interim periods beginning after December 15, 2016. The Company adopted this new guidance on January 1, 2017. The new guidance has since January 1, 2017 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 condensed 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. Upon adoption of the new guidance, the Company also recorded deferred tax assets of $ 4,945, 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 14. 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 condensed 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 will adopt the revenue recognition guidance upon its effective date of January 1, 2018 and it intends to apply the modified cumulative effect approach upon transition. The Company’s implementation efforts include the identification of revenue within the scope of the guidance and the evaluation of revenue contracts. The Company continues to evaluate the potential impact of the new guidance including (i) the timing of revenue recognition for Financial Advisory fees and (ii) the presentation of certain contract costs. With respect to revenue recognition, the Company is assessing the potential impact of the new guidance on the Company’s recognition of certain M&A Advisory fees (e.g., transaction completion, transaction announcement and retainer fees), including whether the Company’s fulfillment of its performance obligations under M&A 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 issue continues to be deliberated by the Financial Reporting Executive Committee of the American Institute of Certified Public Accountants. With respect to the potential impact of the new guidance on the Company’s presentation of certain contract costs, the Company anticipates 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 identified to date 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 Company is currently evaluating the impact of this presentation. 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 early adoption is permitted. The new guidance is to be applied on a retrospective basis. The Company is currently evaluating the new guidance. 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 is currently evaluating the new guidance. Compensation — — — I n 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. 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. This new guidance is effective for annual and interim periods beginning after December 15, 2017, with early adoption permitted. The Company is currently evaluating the new guidance. 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, with early adoption permitted. The new guidance is to be applied on a prospective basis. 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.
Derivative Instruments	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 condensed 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 condensed consolidated statements of operations. In addition to the derivative instruments described above, the Company records derivative liabilities relating to its obligations pertaining to 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 condensed consolidated statements of financial condition. Changes in the fair value of the derivative liabilities are included in “compensation and benefits” in the condensed 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 condensed consolidated statements of operations.
Fair Value Measurement Policy	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 estimated 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. 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 6. 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.
Share-Based Incentive Plan Awards	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 three month and nine month periods ended September 30, 2017 and 2016 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 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.
Employer Contributions to Pension Plans	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.

Receivables (Tables)

Receivables (Tables)	9 Months Ended
	Sep. 30, 2017
Receivables [Abstract]
Schedule of Activity in Allowance for Doubtful Accounts	Activity in the allowance for doubtful accounts for the three month and nine month periods ended September 30, 2017 and 2016 was as follows: Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 Beginning Balance $ 25,094 $ 13,569 $ 16,386 $ 12,882 Bad debt expense, net of recoveries 4,753 1,545 18,584 4,124 Charge-offs, foreign currency translation and other adjustments (2,383 ) (2,147 ) (7,506 ) (4,039 ) Ending Balance $ 27,464 $ 12,967 $ 27,464 $ 12,967

Investments (Tables)

Investments (Tables)	9 Months Ended
	Sep. 30, 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 September 30, 2017 and December 31, 2016: September 30, December 31, 2017 2016 Interest-bearing deposits $ 552 $ 456 Debt 6 - Equities 46,181 41,017 Funds: Alternative investments (a) 23,518 32,441 Debt (a) 86,900 74,597 Equity (a) 191,193 188,268 Private equity 78,376 122,421 379,987 417,727 Equity method 222 222 Total investments 426,948 459,422 Less: Interest-bearing deposits 552 456 Equity method 222 222 Investments, at fair value $ 426,174 $ 458,744 Securities sold, not yet purchased, at fair value (included in “other liabilities”) $ 5,921 $ 4,482 (a) Interests in alternative investment funds, debt funds and equity funds include investments with fair values of $13,850, $48,451 and $124,570, respectively, at September 30, 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 Lazard Fund Interests (“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 6 and 12).
Schedule of Trading Securities Net Unrealized Investment Gains and Losses	During the three month and nine month periods ended September 30, 2017 and 2016, the Company reported in “revenue-other” on its condensed consolidated statements of operations net unrealized investment gains and losses pertaining to “trading” securities still held as of the reporting date as follows: Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 Net unrealized investment gains $ 6,949 $ 9,975 $ 27,932 $ 15,221

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 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	The following tables present, as of September 30, 2017 and December 31, 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: September 30, 2017 Level 1 Level 2 Level 3 NAV Total Assets: Investments: Debt $ 6 $ - $ - $ - $ 6 Equities 44,634 - 1,547 - 46,181 Funds: Alternative investments 15,798 - - 7,720 23,518 Debt 86,894 - - 6 86,900 Equity 191,144 - - 49 191,193 Private equity - - - 78,376 78,376 Derivatives - 3,443 - - 3,443 Total $ 338,476 $ 3,443 $ 1,547 $ 86,151 $ 429,617 Liabilities: Securities sold, not yet purchased $ 5,921 $ - $ - $ - $ 5,921 Contingent consideration liability - - 4,010 - 4,010 Derivatives - 189,142 - - 189,142 Total $ 5,921 $ 189,142 $ 4,010 $ - $ 199,073 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 - - 3,364 - 3,364 Derivatives - 182,223 - - 182,223 Total $ 4,482 $ 182,223 $ 3,364 $ - $ 190,069
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 three month and nine month periods ended September 30, 2017 and 2016: Three Months Ended September 30, 2017 Beginning Balance Net Realized Gains/Losses Included In Earnings (a) Purchases/ Acquisitions Sales/ Dispositions Foreign Currency Translation Adjustments Ending Balance Assets: Investments: Equities $ 3,072 $ 130 $ - $ (1,661 ) $ 6 $ 1,547 Total Level 3 Assets $ 3,072 $ 130 $ - $ (1,661 ) $ 6 $ 1,547 Liabilities: Contingent consideration liability $ 4,108 $ (98 ) $ - $ - $ - $ 4,010 Total Level 3 Liabilities $ 4,108 $ (98 ) $ - $ - $ - $ 4,010 Nine Months Ended September 30, 2017 Beginning Balance Net Realized Gains/Losses Included In Earnings (a) Purchases/ Acquisitions Sales/ Dispositions Foreign Currency Translation Adjustments Ending Balance Assets: Investments: Equities $ 1,508 $ 4 $ 1,661 $ (1,669 ) $ 43 $ 1,547 Total Level 3 Assets $ 1,508 $ 4 $ 1,661 $ (1,669 ) $ 43 $ 1,547 Liabilities: Contingent consideration liability $ 3,364 $ 646 $ - $ - $ - $ 4,010 Total Level 3 Liabilities $ 3,364 $ 646 $ - $ - $ - $ 4,010 Three Months Ended September 30, 2016 Beginning Balance Net Realized Gains / Included In Earnings (a) Purchases/ Acquisitions Sales/ Dispositions Foreign Currency Translation Adjustments Ending Balance Assets: Investments: Equities $ 1,298 $ 2 $ - $ - $ 21 $ 1,321 Total Level 3 Assets $ 1,298 $ 2 $ - $ - $ 21 $ 1,321 Nine Months Ended September 30, 2016 Beginning Balance Net Realized Gains/Losses Included In Earnings (a) Purchases/ Acquisitions Sales/ Dispositions Foreign Currency Translation Adjustments Ending Balance Assets: Investments: Equities $ 1,276 $ 12 $ - $ - $ 33 $ 1,321 Total Level 3 Assets $ 1,276 $ 12 $ - $ - $ 33 $ 1,321 (a) Earnings recorded in “other revenue” for investments in equities for the three month and nine month periods ended September 30, 2017 and the three month and nine month periods ended September 30, 2016 include net unrealized gains of $130, $2, $2 and $7, respectively. Earnings recorded in “amortization and other acquisition-related costs” for the contingent consideration liability for the three month and nine month periods ended September 30, 2017 include unrealized gains (losses) of $98 and $(646), respectively.
Fair Value of Certain Investments Based on NAV	The following tables present, at September 30, 2017 and December 31, 2016, certain investments that are valued using NAV or its equivalent as a practical expedient in determining fair value: September 30, 2017 Estimated Liquidation Period of Investments Not Redeemable Investments Redeemable Fair Value Unfunded Commitments % of Fair Value Not Redeemable % Next 5 Years % 5-10 Years % Thereafter Redemption Frequency Redemption Notice Period Alternative Hedge funds $ 6,617 $ - NA NA NA NA (a) <30-60 days Funds of funds 517 - NA NA NA NA (b) <30-90 days Other 586 - NA NA NA NA (c) <30-60 days Debt funds 6 - NA NA NA NA (d) 30 days Equity funds 49 - NA NA NA NA (e) <30-90 days Private equity funds: Equity growth 78,376 10,085 (f) 100 % 16 % 39 % 45 % NA NA Total $ 86,151 $ 10,085 (a) weekly (51%), monthly (2%) and quarterly (47%) (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 $5,915 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 % Next 5 Years % 5-10 Years % Thereafter Redemption Frequency Redemption Notice Period Alternative Hedge funds $ 6,190 $ - NA NA NA NA (a) <30-60 days Funds of funds 492 - NA NA NA NA (b) <30-90 days Other 443 - NA NA NA NA (c) <30-60 days Debt funds 6 - NA NA NA NA (d) 30 days Equity funds 39 - NA NA NA NA (e) <30-90 days Private equity funds: Equity growth 90,824 9,183 (f) 100 % 12 % 33 % 55 % NA NA Mezzanine debt 31,597 - 100 % - - 100 % NA NA 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)

Derivatives (Tables)	9 Months Ended
	Sep. 30, 2017
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Fair Values of Derivatives Reported on Condensed Consolidated Statements of Financial Condition	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 12) on the accompanying condensed consolidated statements of financial condition as of September 30, 2017 and December 31, 2016: September 30, December 31, 2017 2016 Derivative Assets: Forward foreign currency exchange rate contracts $ 2,938 $ 1,993 Total return swaps and other (a) 505 - $ 3,443 $ 1,993 Derivative Liabilities: Forward foreign currency exchange rate contracts $ 3,835 $ 2,792 Total return swaps and other (a) 9,557 9,043 LFI and other similar deferred compensation arrangements 175,750 170,388 $ 189,142 $ 182,223 (a) For total return swaps, amounts represent the netting of gross derivative assets and liabilities of $509 and $9,561 as of September 30, 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 $17,496 and $16,996 as of September 30, 2017 and December 31, 2016, respectively.
Net Gains and (Losses) with Respect to Derivative Instruments (including Derivatives not Designed as Hedging Instruments)	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 condensed consolidated statements of operations for the three month and nine month periods ended September 30, 2017 and 2016, were as follows: Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 Forward foreign currency exchange rate contracts $ (2,991 ) $ (1,591 ) $ (8,149 ) $ (8,445 ) LFI and other similar deferred compensation arrangements (4,875 ) (6,909 ) (17,981 ) (4,707 ) Total return swaps and other (3,890 ) (3,674 ) (12,872 ) (3,880 ) Total $ (11,756 ) $ (12,174 ) $ (39,002 ) $ (17,032 )

Property (Tables)

Property (Tables)	9 Months Ended
	Sep. 30, 2017
Property Plant And Equipment [Abstract]
Components of Property	At September 30, 2017 and December 31, 2016, property consisted of the following: Estimated Depreciable September 30, December 31, Life in Years 2017 2016 Buildings 33 $ 149,548 $ 132,821 Leasehold improvements 3-20 174,129 175,810 Furniture and equipment 3-10 179,890 172,325 Construction in progress 11,843 14,038 Total 515,410 494,994 Less - Accumulated depreciation and amortization 314,708 285,997 Property $ 200,702 $ 208,997

Goodwill and Other Intangible33

Goodwill and Other Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Components of Goodwill and Other Intangible Assets	The components of goodwill and other intangible assets at September 30, 2017 and December 31, 2016 are presented below: September 30, December 31, 2017 2016 Goodwill $ 362,773 $ 352,124 Other intangible assets (net of accumulated amortization) 5,558 6,858 $ 368,331 $ 358,982
Changes in Carrying Amount of Goodwill	Changes in the carrying amount of goodwill for the nine month periods ended September 30, 2017 and 2016 are as follows: Nine Months Ended September 30, 2017 2016 Balance, January 1 $ 352,124 $ 320,761 Foreign currency translation adjustments 10,649 4,906 Balance, September 30 $ 362,773 $ 325,667
Gross Cost and Accumulated Amortization of Other Intangible Assets	The gross cost and accumulated amortization of other intangible assets as of September 30, 2017 and December 31, 2016, by major intangible asset category, are as follows: September 30, 2017 December 31, 2016 Gross Cost Accumulated Amortization Net Carrying Amount Gross Cost Accumulated Amortization Net Carrying Amount Success/performance fees $ 33,040 $ 27,693 $ 5,347 $ 33,040 $ 26,543 $ 6,497 Management fees, customer relationships and non-compete agreements 33,436 33,225 211 33,436 33,075 361 $ 66,476 $ 60,918 $ 5,558 $ 66,476 $ 59,618 $ 6,858
Estimated Future Amortization Expense	Estimated future amortization expense is as follows: Year Ending December 31, Amortization Expense (a) 2017 (October 1 through December 31) $ 284 2018 5,274 Total amortization expense $ 5,558 (a) Approximately 38% of intangible asset amortization is attributable to a noncontrolling interest.

Senior Debt (Tables)

Senior Debt (Tables)	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Senior Debt	Senior debt is comprised of the following as of September 30, 2017 and December 31, 2016: Outstanding as of Initial Annual September 30, 2017 December 31, 2016 Principal Amount Maturity Date Interest Rate(a) 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 $ 2,878 $ 497,122 $ 500,000 $ 3,569 $ 496,431 Lazard Group 2025 Senior Notes 400,000 2/13/25 3.75 % 400,000 3,479 396,521 400,000 3,833 396,167 Lazard Group 2027 Senior Notes 300,000 3/1/27 3.625 % 300,000 3,707 296,293 300,000 3,998 296,002 Total $ 1,200,000 $ 10,064 $ 1,189,936 $ 1,200,000 $ 11,400 $ 1,188,600 (a) The effective interest rates of Lazard Group’s 4.25% senior notes due November 14, 2020 (the “2020 Notes”), Lazard Group’s 3.75% senior notes due February 13, 2025 (the “2025 Notes”) and Lazard Group’s 3.625% senior notes due March 1, 2027 (the “2027 Notes”) are 4.43%, 3.87% and 3.76%, respectively.

Members' Equity (Tables)

Members' Equity (Tables)	9 Months Ended
	Sep. 30, 2017
Equity [Abstract]
Schedule of Share Repurchase Authorized by Board of Directors	Share Repurchase Program —During the nine month period ended September 30, 2017 and since 2014, the Board of Directors of Lazard authorized the repurchase of Lazard Ltd Class A common stock as set forth in the table below: Date Repurchase Authorization Expiration April 2014 $ 200,000 December February 2015 $ 150,000 December January 2016 $ 200,000 December April 2016 $ 113,182 December November 2016 $ 236,000 December
Schedule Of Share Repurchase Program	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 quarter to quarter due to a variety of factors. Purchases with respect to such program are set forth in the table below: Nine Months Ended September 30: Number of Shares Purchased Average Price Per Share 2016 6,656,250 $ 34.38 2017 5,838,520 $ 43.25
Accumulated Other Comprehensive Income (Loss), Net of Tax	Accumulated Other Comprehensive Income (Loss), Net of Tax (“AOCI”) —The tables below reflect the balances of each component of AOCI at September 30, 2017 and 2016 and activity during the three month and nine month periods then ended: Three Months Ended September 30, 2017 Currency Translation Adjustments Employee Benefit Plans Total AOCI Amount Attributable to Noncontrolling Interests Total Lazard Group AOCI Balance, July 1, 2017 $ (70,684 ) $ (168,133 ) $ (238,817 ) $ (1 ) $ (238,816 ) Activity: Other comprehensive income (loss) before reclassifications 17,818 (4,715 ) 13,103 - 13,103 Adjustments for items reclassified to earnings, net of tax - 1,081 1,081 - 1,081 Net other comprehensive income (loss) 17,818 (3,634 ) 14,184 - 14,184 Balance, September 30, 2017 $ (52,866 ) $ (171,767 ) $ (224,633 ) $ (1 ) $ (224,632 ) Nine Months Ended September 30, 2017 Currency Translation Adjustments Employee Benefit Plans Total AOCI Amount Attributable to Noncontrolling Interests Total Lazard Group AOCI Balance, January 1, 2017 $ (109,306 ) $ (161,471 ) $ (270,777 ) $ (2 ) $ (270,775 ) Activity: Other comprehensive income (loss) before reclassifications 56,440 (13,819 ) 42,621 1 42,620 Adjustments for items reclassified to earnings, net of tax - 3,523 3,523 3,523 Net other comprehensive income (loss) 56,440 (10,296 ) 46,144 1 46,143 Balance, September 30, 2017 $ (52,866 ) $ (171,767 ) $ (224,633 ) $ (1 ) $ (224,632 ) Three Months Ended September 30, 2016 Currency Translation Adjustments Employee Benefit Plans Total AOCI Amount Attributable to Noncontrolling Interests Total Lazard Group AOCI Balance, July 1, 2016 $ (60,965 ) $ (135,382 ) $ (196,347 ) $ (1 ) $ (196,346 ) Activity: Other comprehensive loss before reclassifications (1,828 ) (33 ) (1,861 ) (1 ) (1,860 ) Adjustments for items reclassified to earnings, net of tax - 1,134 1,134 - 1,134 Net other comprehensive income (loss) (1,828 ) 1,101 (727 ) (1 ) (726 ) Balance, September 30, 2016 $ (62,793 ) $ (134,281 ) $ (197,074 ) $ (2 ) $ (197,072 ) Nine Months Ended September 30, 2016 Currency Translation Adjustments Employee Benefit Plans Total AOCI Amount Attributable to Noncontrolling Interests Total Lazard Group AOCI Balance, January 1, 2016 $ (52,687 ) $ (137,073 ) $ (189,760 ) $ (2 ) $ (189,758 ) Activity: Other comprehensive loss before reclassifications (10,106 ) (649 ) (10,755 ) - (10,755 ) Adjustments for items reclassified to earnings, net of tax - 3,441 3,441 - 3,441 Net other comprehensive income (loss) (10,106 ) 2,792 (7,314 ) - (7,314 ) Balance, September 30, 2016 $ (62,793 ) $ (134,281 ) $ (197,074 ) $ (2 ) $ (197,072 )
Adjustments for Items Reclassified Out of AOCI	The table below reflects adjustments for items reclassified out of AOCI, by component, for the three month and nine month periods ended September 30, 2017 and 2016: Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 Amortization relating to employee benefit plans (a) $ 1,285 $ 1,509 $ 4,199 $ 4,612 Less - related income taxes 204 375 676 1,171 Total reclassifications, net of tax $ 1,081 $ 1,134 $ 3,523 $ 3,441 (a) Included in the computation of net periodic benefit cost (see Note 13). Such amounts are included in “compensation and benefits” expense on the condensed consolidated statements of operations.
Net Income Attributable to Noncontrolling Interests	The tables below summarize net income attributable to noncontrolling interests for the three month and nine month periods ended September 30, 2017 and 2016 and noncontrolling interests as of September 30, 2017 and December 31, 2016 in the Company’s condensed consolidated financial statements: Net Income Attributable to Noncontrolling Interests Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 Edgewater $ 2,260 $ 81 $ 5,657 $ 4,988 Other 1 2 3 1 Total $ 2,261 $ 83 $ 5,660 $ 4,989 Noncontrolling Interests as of September 30, December 31, 2017 2016 Edgewater $ 60,050 $ 57,238 Other 12 8 Total $ 60,062 $ 57,246

Incentive Plans (Tables)

Incentive Plans (Tables)	9 Months Ended
	Sep. 30, 2017
Summary of Impact of Share-Based Incentive Plans on Compensation and Benefits Expense	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 condensed consolidated statements of operations for the three month and nine month periods ended September 30, 2017 and 2016: Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 Share-based incentive awards: RSUs $ 39,898 $ 39,447 $ 150,193 $ 134,419 PRSUs 9,896 11,252 38,095 38,276 Restricted Stock 7,697 7,015 30,507 38,833 DSUs 78 53 926 808 Total $ 57,569 $ 57,767 $ 219,721 $ 212,336
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 nine month periods ended September 30, 2017 and 2016: Prepaid Compensation Asset Compensation Liability Balance, January 1, 2017 $ 49,650 $ 170,388 Granted 77,580 77,580 Settled - (95,718 ) Forfeited (866 ) (1,647 ) Amortization (52,702 ) - Change in fair value related to: Increase in fair value of underlying investments - 17,981 Adjustment for estimated forfeitures - 5,333 Other 1,515 1,833 Balance, September 30, 2017 $ 75,177 $ 175,750 Prepaid Compensation Asset Compensation Liability Balance, January 1, 2016 $ 75,703 $ 193,574 Granted 51,871 51,871 Settled - (75,583 ) Forfeited (1,967 ) (3,435 ) Amortization (56,784 ) - Change in fair value related to: Increase in fair value of underlying investments - 4,707 Adjustment for estimated forfeitures - 3,551 Other (1,232 ) 585 Balance, September 30, 2016 $ 67,591 $ 175,270 The following is a summary of the impact of LFI and other similar deferred compensation arrangements on “compensation and benefits” expense within the accompanying condensed consolidated statements of operations for the three month and nine month periods ended September 30, 2017 and 2016: Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 Amortization, net of forfeitures $ 15,961 $ 18,116 $ 57,254 $ 58,867 Change in the fair value of underlying investments 4,875 6,909 17,981 4,707 Total $ 20,836 $ 25,025 $ 75,235 $ 63,574
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 nine month periods ended September 30, 2017 and 2016: RSUs DSUs Units Weighted Average Grant Date Fair Value Units Weighted Average Grant Date Fair Value Balance, January 1, 2017 11,698,138 $ 40.65 276,725 $ 36.05 Granted (including 866,914 RSUs relating to dividend participation) 5,294,156 $ 43.01 41,821 $ 44.30 Forfeited (162,320 ) $ 39.97 - - Vested (3,977,477 ) $ 45.27 (43,465 ) $ 35.77 Balance, September 30, 2017 12,852,497 $ 40.20 275,081 $ 37.35 Balance, January 1, 2016 9,599,658 $ 44.06 312,670 $ 35.98 Granted (including 969,054 RSUs relating to dividend participation) 6,649,625 $ 34.64 46,178 $ 34.98 Forfeited (181,337 ) $ 39.79 - - Vested (4,527,559 ) $ 39.16 (84,759 ) $ 35.30 Balance, September 30, 2016 11,540,387 $ 40.62 274,089 $ 36.02
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 nine month periods ended September 30, 2017 and 2016: Restricted Shares Weighted Average Grant Date Fair Value Balance, January 1, 2017 1,655,073 $ 40.95 Granted 841,355 $ 42.58 Forfeited (65,086 ) $ 40.80 Vested (483,811 ) $ 45.42 Balance, September 30, 2017 1,947,531 $ 40.54 Balance, January 1, 2016 713,738 $ 47.12 Granted 1,795,258 $ 36.74 Forfeited (33,943 ) $ 40.49 Vested (802,276 ) $ 37.09 Balance, September 30, 2016 1,672,777 $ 40.92
PRSUs [Member]
Schedule of Activity Relating to Share-based Awards	The following is a summary of activity relating to PRSUs during the nine month periods ended September 30, 2017 and 2016: PRSUs Weighted Average Grant Date Fair Value Balance, January 1, 2017 1,590,756 $ 40.76 Granted (a) 458,113 $ 43.76 Vested (825,565 ) $ 42.27 Balance, September 30, 2017 1,223,304 $ 40.86 Balance, January 1, 2016 1,019,038 $ 44.49 Granted (a) 627,956 $ 32.91 Vested (417,021 ) $ 38.43 Balance, September 30, 2016 1,229,973 $ 40.63 (a) Represents PRSU awards granted during the relevant year at the target payout level.

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	9 Months Ended
	Sep. 30, 2017
Compensation And Retirement Disclosure [Abstract]
Components of Net Periodic Benefit Cost (Credit)	The following table summarizes the components of net periodic benefit cost (credit) related to the Company’s post-retirement plans for the three month and nine month periods ended September 30, 2017 and 2016: Pension Plans Medical Plan Three Months Ended September 30, 2017 2016 2017 2016 Components of Net Periodic Benefit Cost (Credit): Service cost $ 373 $ 313 $ - $ 3 Interest cost 4,191 4,833 - 42 Expected return on plan assets (6,295 ) (6,648 ) - - Amortization of: Prior service cost - 599 - - Net actuarial loss (gain) 1,285 957 - (47 ) Net periodic benefit cost (credit) $ (446 ) $ 54 $ - $ (2 ) Pension Plans Medical Plan Nine Months Ended September 30, 2017 2016 2017 2016 Components of Net Periodic Benefit Cost (Credit): Service cost $ 1,048 $ 934 $ - $ 9 Interest cost 12,258 15,292 - 125 Expected return on plan assets (18,855 ) (21,047 ) - - Amortization of: Prior service cost 30 1,793 - - Net actuarial loss (gain) 4,169 2,958 - (139 ) Net periodic benefit cost (credit) $ (1,350 ) $ (70 ) $ - $ (5 )

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2017
Segment Reporting [Abstract]
Segment's Contribution with Respect to Net Revenue, Operating Expenses, Operating Income (Loss) and Total Assets	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: Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 Financial Advisory Net Revenue $ 305,890 $ 343,488 $ 1,052,206 $ 896,467 Operating Expenses 243,421 257,561 814,068 718,366 Operating Income $ 62,469 $ 85,927 $ 238,138 $ 178,101 Asset Management Net Revenue $ 320,487 $ 267,725 $ 913,728 $ 767,610 Operating Expenses 217,233 185,753 621,885 543,616 Operating Income $ 103,254 $ 81,972 $ 291,843 $ 223,994 Corporate Net Revenue $ (2,606 ) $ (3,336 ) $ (3,660 ) $ (24,885 ) Operating Expenses 17,923 14,930 52,869 16,196 Operating Loss $ (20,529 ) $ (18,266 ) $ (56,529 ) $ (41,081 ) Total Net Revenue $ 623,771 $ 607,877 $ 1,962,274 $ 1,639,192 Operating Expenses 478,577 458,244 1,488,822 1,278,178 Operating Income $ 145,194 $ 149,633 $ 473,452 $ 361,014 As Of September 30, 2017 December 31, 2016 Total Assets Financial Advisory $ 808,564 $ 883,384 Asset Management 668,410 645,653 Corporate 2,299,126 1,986,947 Total $ 3,776,100 $ 3,515,984

Organization and Basis of Pre39

Organization and Basis of Presentation - Additional Information (Detail) - Segment	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Organization And Basis Of Presentation [Line Items]
Governing operating agreement, date	Oct. 26, 2015
Number of business segments	2
Lazard Ltd [Member]
Organization And Basis Of Presentation [Line Items]
Percentage of common membership interests held	100.00%	100.00%

Recent Accounting Developments

Recent Accounting Developments - Additional Information (Detail) - Adjustments for New Accounting Principle [Member] $ in Thousands	Jan. 01, 2017USD ($)
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	$ 4,945
Deferred tax assets, valuation allowance	$ 12,090

Receivables - Schedule of Activ

Receivables - Schedule of Activity in Allowance for Doubtful Accounts (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Allowance For Doubtful Accounts Receivable Rollforward
Allowance for doubtful accounts receivables, Beginning balance	$ 25,094	$ 13,569	$ 16,386	$ 12,882
Bad debt expense, net of recoveries	4,753	1,545	18,584	4,124
Charge-offs, foreign currency translation and other adjustments	(2,383)	(2,147)	(7,506)	(4,039)
Allowance for doubtful accounts receivables, Ending balance	$ 27,464	$ 12,967	$ 27,464	$ 12,967

Receivables - Additional Inform

Receivables - Additional Information (Detail) - USD ($)	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivables past due or deemed uncollectible	$ 44,372,000		$ 22,212,000
Interest-bearing financing fee receivables	64,965,000		76,133,000
Lazard Ltd subsidiaries	19,434,000		28,702,000
Allowance for doubtful accounts receivables	27,464,000	$ 25,094,000	16,386,000	$ 12,967,000	$ 13,569,000	$ 12,882,000
Aggregate carrying amount of non-interest bearing receivables	502,312,000		570,486,000
Interest-Bearing Receivables [Member] | Lazard Ltd Subsidiaries [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Lazard Ltd subsidiaries	3,742,000		20,365,000
Financing Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for doubtful accounts receivables	$ 0		$ 0

Investments - Company's Investm

Investments - Company's Investments and Securities Sold, Not Yet Purchased (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Schedule of Investments [Line Items]
Total investments	$ 426,948	$ 459,422
Equity method	222	222
Investments, at fair value	426,174	458,744
Securities sold, not yet purchased, at fair value (included in "other liabilities")	5,921	4,482
Interest-bearing Deposits [Member]
Schedule of Investments [Line Items]
Total investments	552	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	46,181	41,017
Investments, at fair value	46,181	41,017
Alternative Investment Funds [Member]
Schedule of Investments [Line Items]
Total investments	23,518	32,441
Investments, at fair value	23,518	32,441
Debt Funds [Member]
Schedule of Investments [Line Items]
Total investments	86,900	74,597
Investments, at fair value	86,900	74,597
Equity Funds [Member]
Schedule of Investments [Line Items]
Total investments	191,193	188,268
Investments, at fair value	191,193	188,268
Private Equity Funds [Member]
Schedule of Investments [Line Items]
Total investments	78,376	122,421
Investments, at fair value	78,376	122,421
Funds Total [Member]
Schedule of Investments [Line Items]
Total investments	$ 379,987	$ 417,727

Investments - Company's Inves44

Investments - Company's Investments and Securities Sold, Not Yet Purchased (Parenthetical) (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Schedule of Investments [Line Items]
Investments	$ 426,948	$ 459,422
Alternative Investment Funds [Member]
Schedule of Investments [Line Items]
Investments	23,518	32,441
Alternative Investment Funds [Member] | Lazard Fund Interests [Member]
Schedule of Investments [Line Items]
Investments	13,850	13,080
Debt Funds [Member]
Schedule of Investments [Line Items]
Investments	86,900	74,597
Debt Funds [Member] | Lazard Fund Interests [Member]
Schedule of Investments [Line Items]
Investments	48,451	37,869
Equity Funds [Member]
Schedule of Investments [Line Items]
Investments	191,193	188,268
Equity Funds [Member] | Lazard Fund Interests [Member]
Schedule of Investments [Line Items]
Investments	$ 124,570	$ 128,219

Investments - Additional Inform

Investments - Additional Information (Detail) - Interest-bearing Deposits [Member]	9 Months Ended
	Sep. 30, 2017
Minimum [Member]
Schedule of Investments [Line Items]
Interest-bearing deposits maturity period	3 months
Maximum [Member]
Schedule of Investments [Line Items]
Interest-bearing deposits maturity period	1 year

Investments - Schedule of Tradi

Investments - Schedule of Trading Securities Net Unrealized Investment Gains and Losses (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Net Realized Or Unrealized Gain Loss On Trading Securities [Abstract]
Net unrealized investment gains	$ 6,949	$ 9,975	$ 27,932	$ 15,221

Fair Value Measurements - Sched

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	Sep. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	$ 426,174	$ 458,744
Total Derivative Assets	3,443	1,993
Total investments measured at fair value	429,617	460,737
Securities sold, not yet purchased	5,921	4,482
Contingent consideration liability	4,010	3,364
Total Derivative Liabilities	189,142	182,223
Total of Liabilities Measured at Fair Value	199,073	190,069
Fair Value, Measurements, Recurring [Member] | NAV [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments measured at fair value	86,151	129,591
Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments measured at fair value	338,476	327,645
Securities sold, not yet purchased	5,921	4,482
Total of Liabilities Measured at Fair Value	5,921	4,482
Level 2 [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Derivative Assets	3,443	1,993
Total investments measured at fair value	3,443	1,993
Total Derivative Liabilities	189,142	182,223
Total of Liabilities Measured at Fair Value	189,142	182,223
Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments measured at fair value	1,547	1,508
Contingent consideration liability	4,010	3,364
Total of Liabilities Measured at Fair Value	4,010	3,364
Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	6
Debt [Member] | Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	6
Equities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	46,181	41,017
Equities [Member] | Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	44,634	39,509
Equities [Member] | Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	1,547	1,508
Alternative Investment Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	23,518	32,441
Alternative Investment Funds [Member] | Fair Value, Measurements, Recurring [Member] | NAV [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	7,720	7,125
Alternative Investment Funds [Member] | Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	15,798	25,316
Debt Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	86,900	74,597
Debt Funds [Member] | Fair Value, Measurements, Recurring [Member] | NAV [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring 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 and Nonrecurring Basis [Line Items]
Investments	86,894	74,591
Equity Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	191,193	188,268
Equity Funds [Member] | Fair Value, Measurements, Recurring [Member] | NAV [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	49	39
Equity Funds [Member] | Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	191,144	188,229
Private Equity Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	78,376	122,421
Private Equity Funds [Member] | Fair Value, Measurements, Recurring [Member] | NAV [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	$ 78,376	$ 122,421

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Changes in Fair Value of Company's Level 3 Assets and Liabilities (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Assets:
Beginning Balance	$ 3,072	$ 1,298	$ 1,508	$ 1,276
Net Unrealized/Realized Gains/Losses Included In Earnings	130	2	4	12
Purchases/Acquisitions	0	0	1,661	0
Sales/Dispositions	(1,661)	0	(1,669)	0
Foreign Currency Translation Adjustments	6	21	43	33
Ending Balance	1,547	1,321	1,547	1,321
Liabilities:
Beginning Balance	4,108		3,364
Net Unrealized/Realized Gains/Losses Included In Earnings	(98)		646
Purchases/Acquisitions	0		0
Sales/Dispositions	0		0
Foreign Currency Translation Adjustments	0		0
Ending Balance	4,010		4,010
Contingent Consideration Liability [Member]
Liabilities:
Beginning Balance	4,108		3,364
Net Unrealized/Realized Gains/Losses Included In Earnings	(98)		646
Purchases/Acquisitions	0		0
Sales/Dispositions	0		0
Foreign Currency Translation Adjustments	0		0
Ending Balance	4,010		4,010
Equities [Member]
Assets:
Beginning Balance	3,072	1,298	1,508	1,276
Net Unrealized/Realized Gains/Losses Included In Earnings	130	2	4	12
Purchases/Acquisitions	0	0	1,661	0
Sales/Dispositions	(1,661)	0	(1,669)	0
Foreign Currency Translation Adjustments	6	21	43	33
Ending Balance	$ 1,547	$ 1,321	$ 1,547	$ 1,321

Fair Value Measurements - Sum49

Fair Value Measurements - Summary of Changes in Fair Value of Company's Level 3 Assets and Liabilities (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Equities [Member]
Fair Value of Assets and Liabilities Measured on Recurring Basis Unobservable Input Reconciliation [Line Items]
Net unrealized gains	$ 130	$ 2	$ 2	$ 7
Contingent Consideration Liability [Member]
Fair Value of Assets and Liabilities Measured on Recurring Basis Unobservable Input Reconciliation [Line Items]
Net unrealized gains (losses)	$ 98		$ (646)

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Fair Value Option Quantitative Disclosures [Line Items]
Transfers between Level 1, 2 and 3 in fair value measurement hierarchy	$ 0	$ 0	$ 0	$ 0
Unfunded Commitments	10,085,000		10,085,000		$ 9,183,000
EGCP III [Member]
Fair Value Option Quantitative Disclosures [Line Items]
Unfunded Commitments	$ 8,613,000		$ 8,613,000
End of the investment period			Oct. 12, 2016
Remaining obligation date			Oct. 12, 2023

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value of Certain Investments Based on NAV (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Fair Value	$ 86,151	$ 129,591
Unfunded Commitments	10,085	9,183
Hedge Funds [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Fair Value	$ 6,617	$ 6,190
Hedge Funds [Member] | Weekly [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Percent	51.00%	73.00%
Hedge Funds [Member] | Monthly [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Percent	2.00%	2.00%
Hedge Funds [Member] | Quarterly [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Percent	47.00%	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	$ 517	$ 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	$ 586	$ 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	$ 49	$ 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	$ 78,376	$ 90,824
Unfunded Commitments	$ 10,085	$ 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	39.00%	33.00%
Estimated Liquidation Period of Investments Not Redeemable, % Thereafter	45.00%	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 - Fai52

Fair Value Measurements - Fair Value of Certain Investments Based on NAV (Parenthetical) (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Fair Value Investments Entities That Calculate Net Asset Value Per Share [Line Items]
Unfunded Commitments	$ 10,085	$ 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	$ 5,915	$ 6,886

Derivatives - Fair Values of De

Derivatives - Fair Values of Derivatives Reported on Condensed Consolidated Statements of Financial Condition (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Derivative Assets	$ 3,443	$ 1,993
Derivative Liabilities	189,142	182,223
Forward Foreign Currency Exchange Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets	2,938	1,993
Derivative Liabilities	3,835	2,792
Total Return Swaps and Other [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets	505
Derivative Liabilities	9,557	9,043
LFI and Other Similar Deferred Compensation Arrangements [Member]
Derivatives, Fair Value [Line Items]
Derivative Liabilities	$ 175,750	$ 170,388

Derivatives - Fair Values of 54

Derivatives - Fair Values of Derivatives Reported on Condensed Consolidated Statements of Financial Condition (Parenthetical) (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Gross derivative liability	$ 175,750	$ 170,388	$ 175,270	$ 193,574
Total Return Swaps [Member]
Derivatives, Fair Value [Line Items]
Gross derivative assets	509	357
Gross derivative liability	9,561	9,400
Cash collateral pledged for total return swaps	$ 17,496	$ 16,996

Derivatives - Net Gains (Losses

Derivatives - Net Gains (Losses) with Respect to Derivative Instruments Not Designated as Hedging Instruments (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on derivatives instruments	$ (11,756)	$ (12,174)	$ (39,002)	$ (17,032)
Forward Foreign Currency Exchange Rate Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on derivatives not designated as hedging instruments	(2,991)	(1,591)	(8,149)	(8,445)
LFI and Other Similar Deferred Compensation Arrangements [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on derivatives not designated as hedging instruments	(4,875)	(6,909)	(17,981)	(4,707)
Total Return Swaps and Other [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on derivatives designated as hedging instruments	$ (3,890)	$ (3,674)	$ (12,872)	$ (3,880)

Property - Components of Proper

Property - Components of Property (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 515,410	$ 494,994
Less - Accumulated depreciation and amortization	314,708	285,997
Property	200,702	208,997
Buildings [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 149,548	132,821
Property, plant and equipment, useful life	33 years
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 174,129	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	$ 179,890	172,325
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	$ 11,843	$ 14,038

Goodwill and Other Intangible57

Goodwill and Other Intangible Assets - Components of Goodwill and Other Intangible Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill	$ 362,773	$ 352,124	$ 325,667	$ 320,761
Other intangible assets (net of accumulated amortization)	5,558	6,858
Goodwill and other intangible assets, Total	$ 368,331	$ 358,982

Goodwill and Other Intangible58

Goodwill and Other Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015
Goodwill And Intangible Assets [Line Items]
Goodwill	$ 362,773	$ 325,667	$ 362,773	$ 325,667	$ 352,124	$ 320,761
Amortization of intangible assets	433	$ 746	1,300	$ 1,720
Financial Advisory Segment [Member]
Goodwill And Intangible Assets [Line Items]
Goodwill	298,232		298,232		287,583
Asset Management Segment [Member]
Goodwill And Intangible Assets [Line Items]
Goodwill	$ 64,541		$ 64,541		$ 64,541

Goodwill and Other Intangible59

Goodwill and Other Intangible Assets - Changes in Carrying Amount of Goodwill (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
Beginning Balance	$ 352,124	$ 320,761
Foreign currency translation adjustments	10,649	4,906
Ending Balance	$ 362,773	$ 325,667

Goodwill and Other Intangible60

Goodwill and Other Intangible Assets - Gross Cost and Accumulated Amortization of Other Intangible Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Other intangible assets, Gross Cost	$ 66,476	$ 66,476
Other intangible assets, Accumulated Amortization	60,918	59,618
Other intangible assets, Net Carrying Amount	5,558	6,858
Success/Performance Fees [Member]
Finite-Lived Intangible Assets [Line Items]
Other intangible assets, Gross Cost	33,040	33,040
Other intangible assets, Accumulated Amortization	27,693	26,543
Other intangible assets, Net Carrying Amount	5,347	6,497
Management Fees, Customer Relationships and Non-Compete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Other intangible assets, Gross Cost	33,436	33,436
Other intangible assets, Accumulated Amortization	33,225	33,075
Other intangible assets, Net Carrying Amount	$ 211	$ 361

Goodwill and Other Intangible61

Goodwill and Other Intangible Assets - Estimated Future Amortization Expense (Detail) $ in Thousands	Sep. 30, 2017USD ($)
Goodwill And Intangible Assets Disclosure [Abstract]
2017 (October 1 through December 31)	$ 284
2,018	5,274
Total amortization expense	$ 5,558

Goodwill and Other Intangible62

Goodwill and Other Intangible Assets - Estimated Future Amortization Expense (Parenthetical) (Detail)	9 Months Ended
	Sep. 30, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Percentage of intangible asset amortization attributable to non-controlling interests	38.00%

Senior Debt - Senior Debt (Deta

Senior Debt - Senior Debt (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Senior Debt, Outstanding Principal	$ 1,200,000,000	$ 1,200,000,000
Senior Debt, Outstanding Unamortized Debt Costs	10,064,000	11,400,000
Senior Debt, Outstanding Carrying Value	1,189,936,000	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	2,878,000	3,569,000
Senior Debt, Outstanding Carrying Value	497,122,000	496,431,000
Lazard Group 3.75% Senior Notes [Member]
Debt Instrument [Line Items]
Senior Debt, Initial Principal Amount	$ 400,000,000
Senior Debt, Maturity Date	Feb. 13, 2025
Senior Debt, Annual Interest Rate	3.75%
Senior Debt, Outstanding Principal	$ 400,000,000	400,000,000
Senior Debt, Outstanding Unamortized Debt Costs	3,479,000	3,833,000
Senior Debt, Outstanding Carrying Value	396,521,000	396,167,000
Lazard Group 3.625% Senior Notes [Member]
Debt Instrument [Line Items]
Senior Debt, Initial Principal Amount	$ 300,000,000
Senior Debt, Maturity Date	Mar. 1, 2027
Senior Debt, Annual Interest Rate	3.625%
Senior Debt, Outstanding Principal	$ 300,000,000	300,000,000
Senior Debt, Outstanding Unamortized Debt Costs	3,707,000	3,998,000
Senior Debt, Outstanding Carrying Value	$ 296,293,000	$ 296,002,000

Senior Debt - Senior Debt (Pare

Senior Debt - Senior Debt (Parenthetical) (Detail)	9 Months Ended
	Sep. 30, 2017
Lazard Group 4.25% Senior Notes [Member]
Debt Instrument [Line Items]
Senior notes interest rate	4.25%
Original Maturity Date	Nov. 14, 2020
Effective interest rates of senior notes	4.43%
Lazard Group 3.75% Senior Notes [Member]
Debt Instrument [Line Items]
Senior notes interest rate	3.75%
Original Maturity Date	Feb. 13, 2025
Effective interest rates of senior notes	3.87%
Lazard Group 3.625% Senior Notes [Member]
Debt Instrument [Line Items]
Senior notes interest rate	3.625%
Original Maturity Date	Mar. 1, 2027
Effective interest rates of senior notes	3.76%

Senior Debt - Additional Inform

Senior Debt - Additional Information (Detail) - USD ($)	Sep. 25, 2015	Sep. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Senior debt		$ 1,189,936,000	$ 1,188,600,000
Unused Lines of Credit [Member]
Debt Instrument [Line Items]
Unused lines of credit		175,000,000
Senior Debt [Member]
Debt Instrument [Line Items]
Senior debt		1,189,936,000	1,188,600,000
Fair value of senior debt		1,230,000,000	1,204,000,000
LFB [Member] | Unused Lines of Credit [Member]
Debt Instrument [Line Items]
Unused lines of credit		24,000,000
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

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($)	3 Months Ended
	Dec. 31, 2016	Sep. 30, 2017
Other Commitments [Line Items]
Guarantees indemnifications		$ 2,948,000
Collateral/counter-guarantees		2,948,000
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 shares earned		0
Business Acquisitions [Member] | Class A Common Stock [Member]
Other Commitments [Line Items]
Common stock issued and issuable	60,817
Business Acquisitions [Member] | Class A Common Stock [Member] | Maximum [Member]
Other Commitments [Line Items]
Contingent shares issuable upon satisfaction of performance thresholds	210,431

Members' Equity - Additional In

Members' Equity - Additional Information (Detail) - USD ($) $ in Thousands	Oct. 25, 2017	Sep. 30, 2017	Sep. 30, 2016
Subsequent Event [Member]
Schedule Of Stockholders Equity [Line Items]
Share repurchase authorized amount	$ 200,000
Expiration	Dec. 31, 2019
November, 2016 [Member]
Schedule Of Stockholders Equity [Line Items]
Share repurchase authorized amount		$ 102,587
Expiration		Dec. 31, 2018
Lazard Ltd Subsidiaries [Member]
Schedule Of Stockholders Equity [Line Items]
Distribution to members		$ 294,966	$ 248,742
Executive Officers [Member]
Schedule Of Stockholders Equity [Line Items]
Shares repurchased, value		$ 14,700	$ 4,900

Members' Equity - Schedule of S

Members' Equity - Schedule of Share Repurchase Authorized by Board of Directors (Detail)	9 Months Ended
	Sep. 30, 2017USD ($)
November, 2016 [Member]
Equity, Class of Treasury Stock [Line Items]
Expiration	Dec. 31, 2018
Class A Common Stock [Member] | April, 2014 [Member]
Equity, Class of Treasury Stock [Line Items]
Share Repurchase Authorization	$ 200,000,000
Expiration	Dec. 31, 2015
Class A Common Stock [Member] | February, 2015 [Member]
Equity, Class of Treasury Stock [Line Items]
Share Repurchase Authorization	$ 150,000,000
Expiration	Dec. 31, 2016
Class A Common Stock [Member] | January, 2016 [Member]
Equity, Class of Treasury Stock [Line Items]
Share Repurchase Authorization	$ 200,000,000
Expiration	Dec. 31, 2017
Class A Common Stock [Member] | April, 2016 [Member]
Equity, Class of Treasury Stock [Line Items]
Share Repurchase Authorization	$ 113,182,000
Expiration	Dec. 31, 2017
Class A Common Stock [Member] | November, 2016 [Member]
Equity, Class of Treasury Stock [Line Items]
Share Repurchase Authorization	$ 236,000,000
Expiration	Dec. 31, 2018

Members' Equity - Schedule of69

Members' Equity - Schedule of Share Repurchase Program (Detail) - $ / shares	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Share Repurchase Program [Abstract]
Number of Shares Purchased	5,838,520	6,656,250
Average Price Per Share	$ 43.25	$ 34.38

Members' Equity - Accumulated O

Members' Equity - Accumulated Other Comprehensive Income (Loss), Net of Tax (Detail) - USD ($) $ in Thousands	3 Months Ended				9 Months Ended
	Sep. 30, 2017		Sep. 30, 2016		Sep. 30, 2017		Sep. 30, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance					$ 736,140	[1]	$ 702,900	[2]
Other comprehensive income (loss) before reclassifications	$ 13,103		$ (1,861)		42,621		(10,755)
Adjustments for items reclassified to earnings, net of tax	1,081		1,134		3,523		3,441
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX	14,184		(727)		46,144		(7,314)
Balance	777,884	[1]	696,195	[2]	777,884	[1]	696,195	[2]
Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(70,684)		(60,965)		(109,306)		(52,687)
Other comprehensive income (loss) before reclassifications	17,818		(1,828)		56,440		(10,106)
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX	17,818		(1,828)		56,440		(10,106)
Balance	(52,866)		(62,793)		(52,866)		(62,793)
Employee Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(168,133)		(135,382)		(161,471)		(137,073)
Other comprehensive income (loss) before reclassifications	(4,715)		(33)		(13,819)		(649)
Adjustments for items reclassified to earnings, net of tax	1,081		1,134		3,523		3,441
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX	(3,634)		1,101		(10,296)		2,792
Balance	(171,767)		(134,281)		(171,767)		(134,281)
Total AOCI [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(238,817)		(196,347)		(270,777)		(189,760)
Balance	(224,633)		(197,074)		(224,633)		(197,074)
AOCI Attributable to Noncontrolling Interest [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(1)		(1)		(2)		(2)
Other comprehensive income (loss) before reclassifications			(1)		1
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX			(1)		1
Balance	(1)		(2)		(1)		(2)
Total Lazard Group AOCI [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(238,816)		(196,346)		(270,775)	[1]	(189,758)	[2]
Other comprehensive income (loss) before reclassifications	13,103		(1,860)		42,620		(10,755)
Adjustments for items reclassified to earnings, net of tax	1,081		1,134		3,523		3,441
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX	14,184		(726)		46,143		(7,314)
Balance	$ (224,632)	[1]	$ (197,072)	[2]	$ (224,632)	[1]	$ (197,072)	[2]
[1]	At both January 1, 2017 and September 30, 2017, in addition to profit participation interests, there were two managing member interests.
[2]	At both January 1, 2016 and September 30, 2016, in addition to profit participation interests, there were two managing member interests.

Members' Equity - Adjustments f

Members' Equity - Adjustments for Items Reclassified Out of AOCI (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications, net of tax	$ 1,081	$ 1,134	$ 3,523	$ 3,441
Accumulated Defined Benefit Plans Adjustment [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Amortization relating to employee benefit plans	1,285	1,509	4,199	4,612
Less - related income taxes	204	375	676	1,171
Total reclassifications, net of tax	$ 1,081	$ 1,134	$ 3,523	$ 3,441

Members' Equity - Net Income At

Members' Equity - Net Income Attributable to Noncontrolling Interests (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Change In Ownership Interest [Line Items]
Net Income Attributable to Noncontrolling Interests	$ 2,261	$ 83	$ 5,660	$ 4,989
Noncontrolling interests	60,062		60,062		$ 57,246
Edgewater [Member]
Change In Ownership Interest [Line Items]
Net Income Attributable to Noncontrolling Interests	2,260	81	5,657	4,988
Noncontrolling interests	60,050		60,050		57,238
Other [Member]
Change In Ownership Interest [Line Items]
Net Income Attributable to Noncontrolling Interests	1	$ 2	3	$ 1
Noncontrolling interests	$ 12		$ 12		$ 8

Incentive Plans - Additional In

Incentive Plans - Additional Information (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend participation rights required the issuance of RSUs	866,914	969,054
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	$ 178,321
Unrecognized compensation expense, years	10 months 25 days
DSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual compensation paid in DSUs	31,280	38,771
Units granted under the directors deferred unit plan	10,541	7,407
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	$ 35,369
Unrecognized compensation expense, years	9 months 18 days
PRSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	$ 11,846
Unrecognized compensation expense, years	9 months 18 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 three years following the date of the grant
Vesting period of PRSUs granted	3 years
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.
Lazard Ltd [Member] | RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Withholding taxes in lieu of share delivery	1,282,843	1,416,643
Delivery of common stock associated with stock awards	2,694,634	3,110,916
Lazard Ltd [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Withholding taxes in lieu of share delivery	147,775	132,984
Delivery of common stock associated with stock awards	336,036	669,292
Lazard Ltd [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
Delivery of common stock associated with stock awards	698,035	352,852
Lazard Ltd [Member] | Awarded Under 2008 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of outstanding Class A common stock	30.00%
Lazard Ltd [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
Lazard Fund Interests [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense, years	10 months 25 days

Incentive Plans - Summary of Im

Incentive Plans - Summary of Impact of Share-Based Incentive Plans on Compensation and Benefits Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Share-based incentive awards:
Share-based incentive awards	$ 57,569	$ 57,767	$ 219,721	$ 212,336
RSUs [Member]
Share-based incentive awards:
Share-based incentive awards	39,898	39,447	150,193	134,419
PRSUs [Member]
Share-based incentive awards:
Share-based incentive awards	9,896	11,252	38,095	38,276
Restricted Stock [Member]
Share-based incentive awards:
Share-based incentive awards	7,697	7,015	30,507	38,833
DSUs [Member]
Share-based incentive awards:
Share-based incentive awards	$ 78	$ 53	$ 926	$ 808

Incentive Plans - Schedule of A

Incentive Plans - Schedule of Activity Relating to RSUs and DSUs (Detail) - $ / shares	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
RSUs [Member]
Share-based compensation arrangement by share-based payment award [Line Items]
Units, Beginning Balance	11,698,138	9,599,658
Units, Granted	5,294,156	6,649,625
Units, Forfeited	(162,320)	(181,337)
Units, Vested	(3,977,477)	(4,527,559)
Units, Ending Balance	12,852,497	11,540,387
Weighted Average Grant Date Fair Value, Beginning Balance	$ 40.65	$ 44.06
Weighted Average Grant Date Fair Value, Granted	43.01	34.64
Weighted Average Grant Date Fair Value, Forfeited	39.97	39.79
Weighted Average Grant Date Fair Value, Vested	45.27	39.16
Weighted Average Grant Date Fair Value, Ending Balance	$ 40.20	$ 40.62
DSUs [Member]
Share-based compensation arrangement by share-based payment award [Line Items]
Units, Beginning Balance	276,725	312,670
Units, Granted	41,821	46,178
Units, Vested	(43,465)	(84,759)
Units, Ending Balance	275,081	274,089
Weighted Average Grant Date Fair Value, Beginning Balance	$ 36.05	$ 35.98
Weighted Average Grant Date Fair Value, Granted	44.30	34.98
Weighted Average Grant Date Fair Value, Vested	35.77	35.30
Weighted Average Grant Date Fair Value, Ending Balance	$ 37.35	$ 36.02

Incentive Plans - Schedule of76

Incentive Plans - Schedule of Activity Relating to RSUs and DSUs (Parenthetical) (Detail) - shares	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Dividend participation rights	866,914	969,054

Incentive Plans - Summary of Ac

Incentive Plans - Summary of Activity Related to Shares of Restricted Class A Common Stock (Detail) - Restricted Stock [Member] - $ / shares	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Share-based compensation arrangement by share-based payment award [Line Items]
Units, Beginning Balance	1,655,073	713,738
Units, Granted	841,355	1,795,258
Units, Forfeited	(65,086)	(33,943)
Units, Vested	(483,811)	(802,276)
Units, Ending Balance	1,947,531	1,672,777
Weighted Average Grant Date Fair Value, Beginning Balance	$ 40.95	$ 47.12
Weighted Average Grant Date Fair Value, Granted	42.58	36.74
Weighted Average Grant Date Fair Value, Forfeited	40.80	40.49
Weighted Average Grant Date Fair Value, Vested	45.42	37.09
Weighted Average Grant Date Fair Value, Ending Balance	$ 40.54	$ 40.92

Incentive Plans - Summary of 78

Incentive Plans - Summary of Activity Relating to PRSUs (Detail) - PRSUs [Member] - $ / shares	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Share-based compensation arrangement by share-based payment award [Line Items]
Units, Beginning Balance	1,590,756	1,019,038
Units, Granted	458,113	627,956
Units, Vested	(825,565)	(417,021)
Units, Ending Balance	1,223,304	1,229,973
Weighted Average Grant Date Fair Value, Beginning Balance	$ 40.76	$ 44.49
Weighted Average Grant Date Fair Value, Granted	43.76	32.91
Weighted Average Grant Date Fair Value, Vested	42.27	38.43
Weighted Average Grant Date Fair Value, Ending Balance	$ 40.86	$ 40.63

Incentive Plans - Summary of LF

Incentive Plans - Summary of LFI and Other Similar Deferred Compensation Arrangements (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Deferred Compensation Arrangements [Abstract]
Prepaid Compensation Asset, Beginning Balance	$ 49,650	$ 75,703
Prepaid Compensation Asset, Granted	77,580	51,871
Prepaid Compensation Asset, Forfeited	(866)	(1,967)
Prepaid Compensation Asset, Amortization	(52,702)	(56,784)
Prepaid Compensation Asset, Other	1,515	(1,232)
Prepaid Compensation Asset, Ending Balance	75,177	67,591
Compensation Liability, Beginning Balance	170,388	193,574
Compensation Liability, Granted	77,580	51,871
Compensation Liability, Settled	(95,718)	(75,583)
Compensation Liability, Forfeited	(1,647)	(3,435)
Compensation Liability, Increase in fair value of underlying investments	17,981	4,707
Compensation Liability, Adjustment for estimated forfeitures	5,333	3,551
Compensation Liability, Other	1,833	585
Compensation Liability, Ending Balance	$ 175,750	$ 175,270

Incentive Plans - Summary of 80

Incentive Plans - Summary of Impact of LFI and Other Similar Deferred Compensation Arrangements (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Share Based Compensation [Abstract]
Amortization, net of forfeitures	$ 15,961	$ 18,116	$ 57,254	$ 58,867
Change in the fair value of underlying investments	4,875	6,909	17,981	4,707
Total	$ 20,836	$ 25,025	$ 75,235	$ 63,574

Employee Benefit Plans - Compon

Employee Benefit Plans - Components of Net Periodic Benefit Cost (Credit) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Pension Plans [Member]
Components of Net Periodic Benefit Cost (Credit):
Service cost	$ 373	$ 313	$ 1,048	$ 934
Interest cost	4,191	4,833	12,258	15,292
Expected return on plan assets	(6,295)	(6,648)	(18,855)	(21,047)
Amortization of:
Prior service cost		599	30	1,793
Net actuarial loss (gain)	1,285	957	4,169	2,958
Net periodic benefit cost (credit)	$ (446)	54	$ (1,350)	(70)
Medical Plan [Member]
Components of Net Periodic Benefit Cost (Credit):
Service cost		3		9
Interest cost		42		125
Amortization of:
Net actuarial loss (gain)		(47)		(139)
Net periodic benefit cost (credit)		$ (2)		$ (5)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Jan. 01, 2017
Income Tax [Line Items]
Income tax provisions (benefits)	$ 27,367	$ 21,653	$ 81,802	$ 49,110
Effective income tax rates	18.80%	14.50%	17.30%	13.60%
U.S. federal statutory income tax rate			35.00%
Adjustments for New Accounting Principle [Member]
Income Tax [Line Items]
Income tax provisions (benefits)			$ (2,047)
Deferred tax assets recorded for previously unrecognized excess tax benefits on share-based payment awards					$ 4,945
Deferred tax assets, valuation allowance					$ 12,090

Related Parties - Additional In

Related Parties - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Related Party Transaction [Line Items]
Lazard Ltd subsidiaries	$ 19,434		$ 19,434		$ 28,702
Asset management fees	301,719	$ 254,551	868,522	$ 729,679
Fees receivable	450,968		450,968		564,291
Lazard Ltd Subsidiaries [Member]
Related Party Transaction [Line Items]
Interest income related to interest-bearing loans	5	23	148	233
Notes payable related parties current and noncurrent	63,726		63,726		60,500
Interest expense related to interest-bearing loans with subsidiaries	976	875	2,851	2,604
Sponsored Funds [Member]
Related Party Transaction [Line Items]
Asset management fees	163,767	$ 130,546	471,727	$ 374,250
Fees receivable	57,156		57,156		49,944
Interest-Bearing Receivables [Member] | Lazard Ltd Subsidiaries [Member]
Related Party Transaction [Line Items]
Lazard Ltd subsidiaries	$ 3,742		$ 3,742		$ 20,365

Regulatory Authorities - Additi

Regulatory Authorities - Additional Information (Detail) - USD ($)	Sep. 30, 2017	Jun. 30, 2017
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	254,141,000
Regulatory capital in excess of minimum requirement	$ 247,866,000
Aggregate indebtedness to net capital ratio	0.37
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	$ 190,884,000
Regulatory capital in excess of minimum requirement	172,104,000
CFLF [Member]
Regulatory Requirements [Line Items]
Regulatory capital	137,988,000
Regulatory capital in excess of minimum requirement	89,582,000
Combined European Regulated Group [Member]
Regulatory Requirements [Line Items]
Regulatory capital		$ 167,325,000
Regulatory capital in excess of minimum requirement		$ 81,079,000
Other U.S. and Non-U.S. Subsidiaries [Member]
Regulatory Requirements [Line Items]
Regulatory capital	151,460,000
Regulatory capital in excess of minimum requirement	$ 124,535,000

Segment Information - Segment's

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		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Segment Reporting Information [Line Items]
Net Revenue	$ 623,771	$ 607,877	$ 1,962,274	$ 1,639,192
Operating Expenses	478,577	458,244	1,488,822	1,278,178
Operating Income (Loss)	145,194	149,633	473,452	361,014
Total Assets	3,776,100		3,776,100		$ 3,515,984
Operating Segments [Member] | Financial Advisory Segment [Member]
Segment Reporting Information [Line Items]
Net Revenue	305,890	343,488	1,052,206	896,467
Operating Expenses	243,421	257,561	814,068	718,366
Operating Income (Loss)	62,469	85,927	238,138	178,101
Total Assets	808,564		808,564		883,384
Operating Segments [Member] | Asset Management Segment [Member]
Segment Reporting Information [Line Items]
Net Revenue	320,487	267,725	913,728	767,610
Operating Expenses	217,233	185,753	621,885	543,616
Operating Income (Loss)	103,254	81,972	291,843	223,994
Total Assets	668,410		668,410		645,653
Corporate [Member]
Segment Reporting Information [Line Items]
Net Revenue	(2,606)	(3,336)	(3,660)	(24,885)
Operating Expenses	17,923	14,930	52,869	16,196
Operating Income (Loss)	(20,529)	$ (18,266)	(56,529)	$ (41,081)
Total Assets	$ 2,299,126		$ 2,299,126		$ 1,986,947