Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement Of Income And Comprehensive Income [Abstract]
NET INCOME	$ 48,196	$ 108,725	$ 218,185	$ 418,765
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX:
Currency translation adjustments	(26,760)	(8,676)	(30,033)	(34,783)
Employee benefit plans:
Actuarial gain (net of tax expense (benefit) of $(1,607) and $214 for the three months ended September 30, 2019 and 2018, respectively, and $1,113 and $618 for the nine months ended September 30, 2019 and 2018, respectively)	9,050	863	11,911	4,149
Adjustment for items reclassified to earnings (net of tax expense of $172 and $264 for the three months ended September 30, 2019 and 2018, respectively, and $524 and $948 for the nine months ended September 30, 2019 and 2018, respectively)	1,074	949	3,319	2,788
OTHER COMPREHENSIVE LOSS, NET OF TAX	(16,636)	(6,864)	(14,803)	(27,846)
COMPREHENSIVE INCOME	31,560	101,861	203,382	390,919
LESS - COMPREHENSIVE INCOME ATTRIBUTABLE TO NONCONTROLLING INTERESTS	1,493	1,653	8,662	5,037
COMPREHENSIVE INCOME ATTRIBUTABLE TO LAZARD LTD	$ 30,067	$ 100,208	$ 194,720	$ 385,882