Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
REVENUE
Interest income	$ 3,029	$ 1,630	$ 7,877	$ 4,893
Total revenue	640,800	638,131	2,180,533	2,005,497
Interest expense	14,319	13,272	41,416	39,994
Net revenue	626,481	624,859	2,139,117	1,965,503
OPERATING EXPENSES
Amortization and other acquisition-related (benefits) costs	(5,851)	172	(13,468)	5,003
Other	14,453	9,031	51,032	30,639
Total operating expenses	487,800	480,647	1,614,668	1,498,593
OPERATING INCOME	138,681	144,212	524,449	466,910
Provision for income taxes	29,956	32,742	105,684	124,109
NET INCOME	108,725	111,470	418,765	342,801
LESS - NET INCOME ATTRIBUTABLE TO NONCONTROLLING INTERESTS	1,651	2,260	5,036	5,660
NET INCOME ATTRIBUTABLE TO LAZARD LTD	$ 107,074	$ 109,210	$ 413,729	$ 337,141
WEIGHTED AVERAGE SHARES OF COMMON STOCK OUTSTANDING:
Basic	119,456,516	121,243,598	119,897,626	122,142,303
Diluted	129,859,728	132,393,664	130,750,392	132,407,551
NET INCOME PER SHARE OF COMMON STOCK:
Basic	$ 0.90	$ 0.90	$ 3.45	$ 2.76
Diluted	0.82	0.82	3.16	2.55
DIVIDENDS DECLARED PER SHARE OF COMMON STOCK	$ 0.44	$ 0.41	$ 2.59	$ 2.40
Investment Banking and Other Advisory Fees [Member]
REVENUE
Revenue	$ 309,690	$ 305,530	$ 1,139,860	$ 1,050,721
Asset Management Fees [Member]
REVENUE
Revenue	312,790	301,719	986,777	868,522
Other [Member]
REVENUE
Revenue	15,291	29,252	46,019	81,361
Compensation and Benefits [Member]
OPERATING EXPENSES
Operating expenses	343,987	361,787	1,165,193	1,138,200
Occupancy and Equipment [Member]
OPERATING EXPENSES
Operating expenses	28,848	29,156	88,326	87,468
Marketing and Business Development [Member]
OPERATING EXPENSES
Operating expenses	21,868	19,798	75,755	63,577
Technology and Information Services [Member]
OPERATING EXPENSES
Operating expenses	36,394	31,373	102,173	87,429
Professional Services [Member]
OPERATING EXPENSES
Operating expenses	13,353	11,005	42,498	33,701
Fund Administration and Outsourced Services [Member]
OPERATING EXPENSES
Operating expenses	$ 34,748	$ 18,325	$ 103,159	$ 52,576