Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2012	Jun. 30, 2012	Jan. 31, 2013 Lazard Ltd Subsidiaries [Member]	Jan. 31, 2013 Class A Common stock [Member]	Jan. 31, 2013 Class B Common stock [Member]
Entity Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2012
Document Fiscal Year Focus	2012
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 Common Stock, Shares Outstanding			12,790,280	128,216,423	1
Entity Public Float		$ 3,018,126,020