Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
REVENUE
Interest income	$ 15,787	$ 13,127	$ 7,144
Total revenue	2,666,958	2,884,833	2,697,829
Interest expense	80,185	58,481	53,518
Net revenue	2,586,773	2,826,352	2,644,311
OPERATING EXPENSES
Compensation and benefits	1,563,395	1,514,735	1,512,873
Occupancy and equipment	123,149	121,107	124,842
Marketing and business development	115,033	108,644	89,205
Technology and information services	143,739	139,693	121,671
Professional services	71,852	61,349	47,932
Fund administration and outsourced services	114,049	132,964	71,305
Amortization and other acquisition-related (benefits) costs	19,410	(15,897)	9,514
Benefit pursuant to tax receivable agreement	(503)	(6,495)	(202,546)
Other	43,951	89,486	44,069
Total operating expenses	2,194,075	2,145,586	1,818,865
OPERATING INCOME	392,698	680,766	825,446
Provision for income taxes	94,982	148,317	565,599
NET INCOME	297,716	532,449	259,847
LESS - NET INCOME ATTRIBUTABLE TO NONCONTROLLING INTERESTS	11,216	5,324	6,264
NET INCOME ATTRIBUTABLE TO LAZARD LTD	$ 286,500	$ 527,125	$ 253,583
WEIGHTED AVERAGE SHARES OF COMMON STOCK OUTSTANDING:
Basic	110,189,862	119,006,531	121,573,442
Diluted	116,079,806	129,767,592	132,479,728
NET INCOME PER SHARE OF COMMON STOCK:
Basic	$ 2.57	$ 4.43	$ 2.09
Diluted	$ 2.44	$ 4.06	$ 1.91
Investment Banking and Other Advisory Fees [Member]
REVENUE
Revenue	$ 1,371,420	$ 1,554,114	$ 1,385,536
Asset Management Fees [Member]
REVENUE
Revenue	1,180,857	1,268,399	1,195,550
Other [Member]
REVENUE
Revenue	$ 98,894	$ 49,193	$ 109,599