Net Income Per Share of Common Stock - Company's Basic and Diluted Net Income Per Share and Weighted Average Shares Outstanding (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Earnings Per Share [Abstract]
Net income attributable to Lazard Ltd	$ 113,876	$ 87,300
Add - adjustment for earnings attributable to participating securities	(1,733)	(1,292)
Net income attributable to Lazard Ltd - basic	112,143	86,008
Add - adjustment for earnings attributable to participating securities	1,129	1,292
Net income attributable to Lazard Ltd - diluted	$ 113,272	$ 87,300
Weighted average number of shares of common stock outstanding	100,634,720	105,545,273
Add - adjustment for shares of common stock issuable on a non-contingent basis	1,912,557	1,746,287
Weighted average number of shares of common stock outstanding - basic	102,547,277	107,291,560
Weighted average number of incremental shares of common stock issuable from share-based incentive compensation	5,639,365	8,530,734
Weighted average number of shares of common stock outstanding - diluted	108,186,642	115,822,294
Net income attributable to Lazard Ltd per share of common stock:
Basic	$ 1.09	$ 0.80
Diluted	$ 1.05	$ 0.75