Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]		Additional Paid-In-Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss), Net of Tax [Member]	Class A Common Stock Held By Subsidiaries [Member]	Total Lazard Ltd Stockholders' Equity [Member]	Noncontrolling Interests [Member]	Series A Preferred Stock [Member]
Balance at Dec. 31, 2015	$ 1,367,306	$ 1,298		$ 600,034	$ 1,123,728	$ (234,356)	$ (177,249)	$ 1,313,455	$ 53,851
Balance (in shares) at Dec. 31, 2015		129,766,091	[1]				4,253,381			7,921
Comprehensive income (loss)
Net income	393,692				387,698			387,698	5,994
Other comprehensive income (loss) - net of tax	(79,867)					(79,866)		(79,866)	(1)
Settlement of Series A preferred stock (in shares)										(7,921)
Amortization of share-based incentive compensation	261,462			261,462				261,462
Dividend equivalents	(3,818)			37,284	(41,102)			(3,818)
Class A common stock dividends ($2.69 per share for 2016, $2.81 per share for 2017 and $3.03 per share for 2018)	(336,138)				(336,138)			(336,138)
Purchase of Class A common stock	$ (300,217)						$ (300,217)	(300,217)
Purchase of Class A common stock (in shares)	8,551,271						8,551,271
Delivery of Class A common stock in connection with share-based incentive compensation and related tax benefit (expense)	$ (55,630)			(224,201)			$ 168,571	(55,630)
Delivery of Class A common stock in connection with shared-based incentive compensation and related tax benefit (expense) (in shares)							(4,235,455)
Business acquisitions and related equity transactions:
Class A common stock issuable (including related amortization)	37,861			37,861				37,861
Delivery of Class A common stock and related tax benefit (expense)	1,621			(33,768)			$ 35,389	1,621
Delivery of Class A common stock and related tax benefit (expense) (in shares)							(940,411)
Distributions to noncontrolling interests, net	(2,018)								(2,018)
Other	9,559			9,559				9,559
Balance at Dec. 31, 2016	1,293,813	$ 1,298		688,231	1,134,186	(314,222)	$ (273,506)	1,235,987	57,826
Balance (in shares) at Dec. 31, 2016		129,766,091	[1]				7,628,786
Adjustment for the cumulative effect on prior years from the adoption of new accounting guidance related to share-based incentive compensation at Dec. 31, 2016	81,544				81,544			81,544
Balance, as adjusted at Dec. 31, 2016	1,375,357	$ 1,298		688,231	1,215,730	(314,222)	$ (273,506)	1,317,531	57,826
Comprehensive income (loss)
Net income	259,847				253,583			253,583	6,264
Other comprehensive income (loss) - net of tax	81,705					81,704		81,704	1
Amortization of share-based incentive compensation	272,965			272,965				272,965
Dividend equivalents	(5,908)			41,746	(47,654)			(5,908)
Class A common stock dividends ($2.69 per share for 2016, $2.81 per share for 2017 and $3.03 per share for 2018)	(341,450)				(341,450)			(341,450)
Purchase of Class A common stock	$ (306,741)						$ (306,741)	(306,741)
Purchase of Class A common stock (in shares)	6,956,097						6,956,097
Delivery of Class A common stock in connection with share-based incentive compensation and related tax benefit (expense)	$ (73,170)			(213,978)			$ 140,808	(73,170)
Delivery of Class A common stock in connection with shared-based incentive compensation and related tax benefit (expense) (in shares)							(3,790,267)
Business acquisitions and related equity transactions:
Class A common stock issuable (including related amortization)	508			508				508
Delivery of Class A common stock and related tax benefit (expense)	577			(1,332)			$ 1,909	577
Delivery of Class A common stock and related tax benefit (expense) (in shares)							(47,474)
Distributions to noncontrolling interests, net	(5,193)								(5,193)
Other	408				204			204	204
Balance at Dec. 31, 2017	1,258,905	$ 1,298		788,140	1,080,413	(232,518)	$ (437,530)	1,199,803	59,102
Balance (in shares) at Dec. 31, 2017		129,766,091	[1]				10,747,142
Comprehensive income (loss)
Net income	532,449				527,125			527,125	5,324
Other comprehensive income (loss) - net of tax	(41,301)					(41,300)		(41,300)	(1)
Amortization of share-based incentive compensation	267,573			267,573				267,573
Dividend equivalents	(6,328)			44,255	(50,583)			(6,328)
Class A common stock dividends ($2.69 per share for 2016, $2.81 per share for 2017 and $3.03 per share for 2018)	(359,639)				(359,639)			(359,639)
Purchase of Class A common stock	$ (552,872)						$ (552,872)	(552,872)
Purchase of Class A common stock (in shares)	12,206,652
Delivery of Class A common stock in connection with share-based incentive compensation and related tax benefit (expense)	$ (118,072)			(350,481)			$ 232,409	(118,072)
Delivery of Class A common stock in connection with shared-based incentive compensation and related tax benefit (expense) (in shares)							(5,353,920)
Business acquisitions and related equity transactions:
Class A common stock issuable (including related amortization)	561			561				561
Delivery of Class A common stock and related tax benefit (expense)				(1,109)			$ 1,109
Delivery of Class A common stock and related tax benefit (expense) (in shares)							25,069
Dividend-equivalents				1,753	(1,753)
Distributions to noncontrolling interests, net	(11,183)								(11,183)
Balance at Dec. 31, 2018	$ 970,093	$ 1,298		$ 750,692	$ 1,195,563	$ (273,818)	$ (756,884)	$ 916,851	$ 53,242
Balance (in shares) at Dec. 31, 2018		129,766,091	[1]				17,574,805

[1] Includes 129,766,091 shares of the Company’s Class A common stock issued at December 31, 2016, 2017 and 2018, respectively.