Condensed 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				4,253,381			7,921
Comprehensive income (loss):
Net income	152,087			147,180			147,180	4,907
Other comprehensive income (loss) - net of tax	(2,674)				(2,674)		(2,674)
Amortization of share-based incentive compensation	155,325		155,325				155,325
Dividend-equivalents	(2,327)		28,364	(30,691)			(2,327)
Class A common stock dividends	(242,085)			(242,085)			(242,085)
Purchase of Class A common stock	$ (194,729)					$ (194,729)	(194,729)
Purchase of Class A common stock (in shares)	5,646,092					5,646,092
Delivery of Class A common stock in connection with share-based incentive compensation and related tax expense/benefit	$ (47,074)		(203,406)			$ 156,332	(47,074)
Delivery of Class A common stock in connection with share-based incentive compensation and related tax expense/benefit (in shares)						(3,889,417)
Business acquisitions and related equity transactions:
Delivery of Class A common stock and related tax benefit	11,126		(19,167)			$ 30,293	11,126
Delivery of Class A common stock and related tax benefit (in shares)						(799,437)
Distributions to noncontrolling interests, net	(615)							(615)
Other	8,004		8,004				8,004
Balance at Jun. 30, 2016	1,204,344	$ 1,298	569,154	998,132	(237,030)	$ (185,353)	1,146,201	58,143
Balance (in shares) at Jun. 30, 2016		129,766,091				5,210,619			7,921
Balance at Mar. 31, 2016					(221,572)
Comprehensive income (loss):
Net income	81,364
Other comprehensive income (loss) - net of tax	(15,458)				(15,458)
Balance at Jun. 30, 2016	1,204,344	$ 1,298	569,154	998,132	(237,030)	$ (185,353)	1,146,201	58,143
Balance (in shares) at Jun. 30, 2016		129,766,091				5,210,619			7,921
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				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	231,331			227,931			227,931	3,400
Other comprehensive income (loss) - net of tax	36,437				36,437		36,437
Amortization of share-based incentive compensation	163,001		163,001				163,001
Dividend-equivalents	(4,077)		31,335	(35,412)			(4,077)
Class A common stock dividends	(242,427)			(242,427)			(242,427)
Purchase of Class A common stock	$ (184,892)					$ (184,892)	(184,892)
Purchase of Class A common stock (in shares)	4,268,479					4,268,479
Delivery of Class A common stock in connection with share-based incentive compensation and related tax expense/benefit	$ (70,900)		(209,543)			$ 138,643	(70,900)
Delivery of Class A common stock in connection with share-based incentive compensation and related tax expense/benefit (in shares)						(3,736,461)
Business acquisitions and related equity transactions:
Class A common stock issuable(including related amortization)	218		218				218
Distributions to noncontrolling interests, net	(1,743)							(1,743)
Other	408			204			204	204
Balance at Jun. 30, 2017	1,302,713	$ 1,298	673,242	1,166,026	(277,785)	$ (319,755)	1,243,026	59,687
Balance (in shares) at Jun. 30, 2017		129,766,091				8,160,804
Balance at Mar. 31, 2017					(296,699)
Comprehensive income (loss):
Net income	120,901
Other comprehensive income (loss) - net of tax	18,914				18,914
Balance at Jun. 30, 2017	$ 1,302,713	$ 1,298	$ 673,242	$ 1,166,026	$ (277,785)	$ (319,755)	$ 1,243,026	$ 59,687
Balance (in shares) at Jun. 30, 2017		129,766,091				8,160,804