Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement Of Income And Comprehensive Income [Abstract]
NET INCOME	$ 120,901	$ 81,364	$ 231,331	$ 152,087
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX:
Currency translation adjustments (including a tax benefit of $1,723 for the three months ended June 30, 2016 and $2,869 for the six months ended June 30, 2016)	26,167	(16,104)	43,099	(4,365)
Employee benefit plans:
Actuarial loss (net of tax benefit of $2,215 and $228 for the three months ended June 30, 2017 and 2016, respectively, and $2,476 and $298 for the six months ended June 30, 2017 and 2016, respectively)	(8,609)	(475)	(9,104)	(616)
Adjustment for items reclassified to earnings (net of tax expense of $196 and $403 for the three months ended June 30, 2017 and 2016, respectively, and $472 and $796 for the six months ended June 30, 2017 and 2016, respectively)	1,356	1,121	2,442	2,307
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX	18,914	(15,458)	36,437	(2,674)
COMPREHENSIVE INCOME	139,815	65,906	267,768	149,413
LESS - COMPREHENSIVE INCOME ATTRIBUTABLE TO NONCONTROLLING INTERESTS	523	1,007	3,400	4,907
COMPREHENSIVE INCOME ATTRIBUTABLE TO LAZARD LTD	$ 139,292	$ 64,899	$ 264,368	$ 144,506