Organization and Basis of Presentation - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013 Segment	Dec. 31, 2013 Class B Common Stock [Member]	Dec. 31, 2012 Class B Common Stock [Member]	Dec. 31, 2013 Class A Common Stock [Member]	Dec. 31, 2012 Class A Common Stock [Member]	Dec. 31, 2013 Lazard Ltd [Member]	Dec. 31, 2012 Lazard Ltd [Member]	Dec. 31, 2013 LAZ-MD Holdings LLC [Member]	Dec. 31, 2012 LAZ-MD Holdings LLC [Member]	Dec. 31, 2013 LAZ-MD Holdings LLC [Member] Class B Common Stock [Member]	Dec. 31, 2013 LAZ-MD Holdings LLC [Member] Class A Common Stock [Member]	Dec. 31, 2012 LAZ-MD Holdings LLC [Member] Class A Common Stock [Member]
Organization And Basis Of Presentation [Line Items]
Percentage of common membership interests held						99.50%	98.80%	0.50%	1.20%
Governing Operating Agreement, date	May 10, 2005
Common membership voting power held											0.50%	1.20%
Common stock, par value		$ 0.01	$ 0.01	$ 0.01	$ 0.01
Common stock, shares outstanding		1	1							1
Common stock, shares issued		1	1	129,056,081	128,216,423					1
Number of business segments	2