Condensed Consolidated Statements of Changes in Stockholders' Equity (USD $) In Thousands, except Share data, unless otherwise specified		Total USD ($)	Series A Preferred Stock [Member]	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 ($)	Total Lazard Ltd Stockholder's Equity [Member] USD ($)	Noncontrolling Interests [Member] USD ($)
Beginning Balance at Dec. 31, 2012		$ 651,540		$ 1,282		$ 846,050	$ 182,647	$ (110,541)	$ (349,782)	$ 569,656	$ 81,884
Beginning Balance (in shares) at Dec. 31, 2012			7,921	128,216,424	[1]				12,802,938
Comprehensive income (loss):
NET INCOME		112,318					106,995			106,995	5,323
Other comprehensive income (loss) - net of tax		(16,835)						(16,713)		(16,713)	(122)
Business acquisitions and related equity transactions:
Class A common stock issuable (including related amortization)		834				829				829	5
Delivery of Class A common stock (including dividend-equivalents)						(4,994)	(179)		5,173
Delivery of Class A common stock (including dividend-equivalents) (in shares)									(170,988)
Amortization of share-based incentive compensation		183,341				182,338				182,338	1,003
Dividend-equivalents		(165)				8,440	(8,604)			(164)	(1)
Class A common stock dividends		(60,931)					(60,931)			(60,931)
Purchase of Class A common stock		(77,934)							(77,934)	(77,934)
Purchase of Class A common stock (in shares)									2,201,657
Delivery of Class A common stock in connection with shared-based incentive compensation and related tax benefit		(124,684)				(342,898)	(609)		218,819	(124,688)	4
Delivery of Class A common stock in connection with share-based incentive compensation and related tax benefit (in shares)									(7,519,848)
Class A common stock issued in exchange for Lazard Group common membership interests				8		(8)
Class A common stock issued in exchange for Lazard Group common membership interests (in shares)	[1]			839,658
Distributions to noncontrolling interests, net		(9,423)									(9,423)
Adjustments related to noncontrolling interests		(1,000)				3,984		(598)		3,386	(4,386)
Ending Balance at Sep. 30, 2013		657,061		1,290		693,741	219,319	(127,852)	(203,724)	582,774	74,287
Ending Balance (in shares) at Sep. 30, 2013			7,921	129,056,082	[1]				7,313,759
Beginning Balance at Dec. 31, 2013		629,998		1,291		737,899	203,236	(133,004)	(249,213)	560,209	69,789
Beginning Balance (in shares) at Dec. 31, 2013			7,921	129,056,082	[2]				8,317,065
Comprehensive income (loss):
NET INCOME		261,258					254,893			254,893	6,365
Other comprehensive income (loss) - net of tax		(18,621)						(18,621)		(18,621)
Business acquisitions and related equity transactions:
Class A common stock issuable (including related amortization)		387				387				387
Amortization of share-based incentive compensation		159,095				159,095				159,095
Dividend-equivalents		(1,754)				13,489	(15,243)			(1,754)
Class A common stock dividends		(109,592)					(109,592)			(109,592)
Purchase of Class A common stock		(192,657)							(192,657)	(192,657)
Purchase of Class A common stock (in shares)									4,114,206
Delivery of Class A common stock in connection with shared-based incentive compensation and related tax benefit		(82,374)				(257,127)			174,753	(82,374)
Delivery of Class A common stock in connection with share-based incentive compensation and related tax benefit (in shares)									(4,828,479)
Class A common stock issued in exchange for Lazard Group common membership interests				7		(7)
Class A common stock issued in exchange for Lazard Group common membership interests (in shares)	[2]			710,009
Distributions to noncontrolling interests, net		(8,080)									(8,080)
Adjustments related to noncontrolling interests						3,543		(559)		2,984	(2,984)
Ending Balance at Sep. 30, 2014		$ 637,660		$ 1,298		$ 657,279	$ 333,294	$ (152,184)	$ (267,117)	$ 572,570	$ 65,090
Ending Balance (in shares) at Sep. 30, 2014			7,921	129,766,091	[2]				7,602,792

[1] Includes 128,216,423 and 129,056,081 shares of the Company's Class A common stock issued at January 1, 2013 and September 30, 2013, respectively, and 1 share of the Company's Class B common stock issued at each such date.

[2] Includes 129,056,081 and 129,766,091 shares of the Company's Class A common stock issued at January 1, 2014 and September 30, 2014, respectively, and 1 share of the Company's Class B common stock issued at January 1, 2014.