Incentive Plans - Summary of Impact of Fund Interests and Other Similar Deferred Compensation Arrangements (Parenthetical) (Detail) (Lazard Fund Interests and other similar deferred compensation arrangements [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013
Lazard Fund Interests and other similar deferred compensation arrangements [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Staff reductions and Cost Savings Initiatives	$ 917