Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2015	Jan. 29, 2016	Jun. 30, 2015
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2015
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	FY
Trading Symbol	LAZ
Entity Registrant Name	LAZARD LTD
Entity Central Index Key	0001311370
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 7,014,008,156
Class A Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		129,766,091
Class A Common Stock [Member] | Subsidiaries of Lazard Ltd [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		4,449,396