Incentive Plans - Additional Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended				12 Months Ended			12 Months Ended	1 Months Ended			12 Months Ended	1 Months Ended		12 Months Ended				12 Months Ended													12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012 RSUs [Member]	Dec. 31, 2013 RSUs [Member]	Dec. 31, 2011 RSUs [Member]	Dec. 31, 2013 Liability Awards [Member] RSUs [Member]	Dec. 31, 2012 Liability Awards [Member] RSUs [Member]	Mar. 31, 2013 Liability Awards [Member] RSUs [Member]	Dec. 31, 2013 Lazard Fund Interests [Member]	Feb. 28, 2014 Subsequent Event [Member]	Feb. 28, 2014 Subsequent Event [Member] RSUs [Member]	Feb. 28, 2014 Subsequent Event [Member] PRSUs [Member]	Dec. 31, 2013 Non-Executive [Member]	Feb. 28, 2014 One-Third Vesting [Member] Subsequent Event [Member] RSUs [Member]	Feb. 28, 2014 Two-Thirds Vesting [Member] Subsequent Event [Member] RSUs [Member]	Dec. 31, 2013 PRSUs [Member]	Dec. 31, 2013 PRSUs [Member] March 2015 [Member]	Dec. 31, 2013 PRSUs [Member] March 2016 [Member]	Feb. 28, 2014 PRSUs [Member] Subsequent Event [Member]	Dec. 31, 2013 PRSUs [Member] Executive Officers [Member]	Dec. 31, 2013 DSUs [Member]	Dec. 31, 2012 DSUs [Member]	Dec. 31, 2011 DSUs [Member]	Dec. 31, 2013 RSUs [Member]	Dec. 31, 2012 RSUs [Member]	Dec. 31, 2011 RSUs [Member]	Dec. 31, 2013 Restricted Stock [Member]	Dec. 31, 2012 Class A Common Stock [Member]	Dec. 31, 2013 Class A Common Stock [Member] RSUs [Member]	Dec. 31, 2012 Class A Common Stock [Member] RSUs [Member]	Dec. 31, 2011 Class A Common Stock [Member] RSUs [Member]	Dec. 31, 2013 Class A Common Stock [Member] 2005 Plan [Member]	Dec. 31, 2013 Class A Common Stock [Member] Awarded under 2008 Plan [Member]	Dec. 31, 2013 Class A Common Stock [Member] Restricted Stock [Member]	Dec. 31, 2012 Class A Common Stock [Member] Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized pertaining to share based compensation arrangements, 2005 Plan																															25,000,000
Percentage of outstanding Class A common stock																																30.00%
Percentage of annual compensation received by directors in the form of DSUs												55.00%
Annual compensation paid in DSUs																				39,315	53,239	26,859
Units granted under the directors deferred unit plan																				7,623	10,597	8,184
Units, vested		7,284,031	9,768,849	8,054,387
RSUs exchanged for shares of restricted Class A common stock		1,523,642																									1,523,642
RSUs modified through a forward purchase agreement						958,213
Liability award							$ 28,612
Liability awards, compensation expense					1,690
Amount recorded in accrued compensation expense related to liability award after amortization						26,922
Withholding taxes in lieu of share delivery																												3,651,050	1,471,814	2,353,561			18,599	28,129
Delivery of common stock associated with stock awards																												6,117,799	3,330,362	5,700,826			1,709,910	174,381
Unrecognized compensation expense															19,430								156,537			7,361
Unrecognized compensation expense, years								1 year 6 months		2 years 8 months 12 days					1 year 4 months 24 days								1 year			1 year 2 months 12 days
Shares granted																			448,128	46,938	63,836	35,043	5,174,810	8,594,744	7,002,736
Vesting period associated with PRSUs																33.00%	67.00%
Percentage of target number of shares subject to each PRSU no longer subject to forfeiture due to threshold level of performance being achieved	25.00%
Weighted Average Grant Date Fair Value, Granted																			$ 36.11	$ 34.42	$ 24.06	$ 36.09	$ 37.21	$ 27.68	$ 43.21
Deferred incentive awards excluding PRSUs									275,000
Grant date fair value amount																		$ 16,000
Incentive awards - RSUs, vesting date													Mar. 01, 2016	Mar. 01, 2017
Incentive awards - PSRUs granted for cliff, vesting period											2017-03