Condensed Consolidated Statements of Changes in Stockholders' Equity (USD $) In Thousands, except Share data, unless otherwise specified	Total USD ($)	Common Stock [Member] USD ($)		Additional Paid-In-Capital [Member] USD ($)	Retained Earnings [Member] USD ($)	Accumulated Other Comprehensive Income (Loss), Net of Tax [Member] USD ($)	Class A Common Stock Held By Subsidiaries [Member] USD ($)	Total Lazard Ltd Stockholders' Equity [Member] USD ($)	Noncontrolling Interests [Member] USD ($)	Series A Preferred Stock [Member]
Balance at Dec. 31, 2013	$ 629,998	$ 1,291		$ 737,899	$ 203,236	$ (133,004)	$ (249,213)	$ 560,209	$ 69,789
Balance (in shares) at Dec. 31, 2013		129,056,082	[1]				8,317,065			7,921
Comprehensive income (loss):
NET INCOME	85,429				80,842			80,842	4,587
Other comprehensive income (loss) - net of tax	6,645					6,621		6,621	24
Business acquisitions and related equity transactions:
Class A common stock issuable (including related amortization)	129			128				128	1
Amortization of share-based incentive compensation	60,797			60,464				60,464	333
Dividend-equivalents	(332)			5,013	(5,343)			(330)	(2)
Class A common stock dividends	(35,917)				(35,917)			(35,917)
Purchase of Class A common stock	(106,935)						(106,935)	(106,935)
Purchase of Class A common stock (in shares)							2,392,674
Delivery of Class A common stock in connection with shared-based incentive compensation and related tax benefit	(80,245)			(247,810)			167,555	(80,255)	10
Delivery of Class A common stock in connection with shared-based incentive compensation and related tax benefit (in shares)							(4,649,300)
Distributions to noncontrolling interests, net	(3,928)								(3,928)
Adjustments related to noncontrolling interests				1,017				1,017	(1,017)
Balance at Mar. 31, 2014	555,641	1,291		556,711	242,818	(126,383)	(188,593)	485,844	69,797
Balance (in shares) at Mar. 31, 2014		129,056,082	[1]				6,060,439			7,921
Balance at Dec. 31, 2014	770,057	1,298		702,800	464,655	(200,766)	(261,243)	706,744	63,313
Balance (in shares) at Dec. 31, 2014		129,766,091					7,450,745			7,921
Comprehensive income (loss):
NET INCOME	62,646				55,953			55,953	6,693
Other comprehensive income (loss) - net of tax	(32,728)					(32,728)		(32,728)
Business acquisitions and related equity transactions:
Class A common stock issuable (including related amortization)	89			89				89
Amortization of share-based incentive compensation	77,923			77,923				77,923
Dividend-equivalents	(1,155)			22,898	(24,053)			(1,155)
Class A common stock dividends	(158,390)				(158,390)			(158,390)
Purchase of Class A common stock	(82,963)						(82,963)	(82,963)
Purchase of Class A common stock (in shares)							1,677,464
Delivery of Class A common stock in connection with shared-based incentive compensation and related tax benefit	(92,390)			(294,327)			201,937	(92,390)
Delivery of Class A common stock in connection with shared-based incentive compensation and related tax benefit (in shares)							(5,370,128)
Distributions to noncontrolling interests, net	(5,784)								(5,784)
Balance at Mar. 31, 2015	$ 537,305	$ 1,298		$ 509,383	$ 338,165	$ (233,494)	$ (142,269)	$ 473,083	$ 64,222
Balance (in shares) at Mar. 31, 2015		129,766,091					3,758,081			7,921

[1] Includes 129,056,081 shares of the Company's Class A common stock issued at January 1, 2014 and March 31, 2014, and 1 share of the Company's Class B common stock issued at each such date.