Schedule I - Condensed Statements of Comprehensive Income (Parent Company Only) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
NET INCOME	$ 528,064	$ 402,461	$ 286,500
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX:
Currency translation adjustments before reclassification	(48,099)	52,862	9,551
Adjustment for items reclassified to earnings	23,645
Employee benefit plans:
Actuarial gain (loss) (net of tax expense (benefit) of $13,263, $(1,431) and $(9,236) for the years ended December 31, 2021, 2020 and 2019, respectively)	33,315	(3,626)	(34,098)
Adjustments for items reclassified to earnings (net of tax expense of $1,609, $1,476 and $1,167 for the years ended December 31, 2021, 2020 and 2019, respectively)	5,660	6,046	4,717
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX	14,521	55,282	(19,830)
COMPREHENSIVE INCOME ATTRIBUTABLE TO LAZARD LTD	542,585	457,741	266,670
Parent Company [Member]
NET INCOME	528,064	402,461	286,500
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX:
Currency translation adjustments before reclassification	(48,099)	52,860	9,551
Adjustment for items reclassified to earnings	23,645
Employee benefit plans:
Actuarial gain (loss) (net of tax expense (benefit) of $13,263, $(1,431) and $(9,236) for the years ended December 31, 2021, 2020 and 2019, respectively)	33,315	(3,626)	(34,098)
Adjustments for items reclassified to earnings (net of tax expense of $1,609, $1,476 and $1,167 for the years ended December 31, 2021, 2020 and 2019, respectively)	5,660	6,046	4,717
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX	14,521	55,280	(19,830)
COMPREHENSIVE INCOME ATTRIBUTABLE TO LAZARD LTD	$ 542,585	$ 457,741	$ 266,670