Segment Information - Segment's Contribution with Respect to Net Revenue, Operating Expenses, Operating Income (Loss) and Total Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Net Revenue	$ 3,193,048	$ 2,566,138	$ 2,586,773
Operating Expenses	2,469,200	2,063,997	2,194,075
Operating Income (Loss)	723,848	502,141	392,698
Total Assets	7,147,181	5,971,861	5,639,581
Depreciation and amortization of property	38,315	35,095	35,572
Operating Segments [Member] | Financial Advisory Segment [Member]
Segment Reporting Information [Line Items]
Net Revenue	1,764,509	1,420,501	1,374,036
Operating Expenses	1,356,567	1,130,850	1,225,795
Operating Income (Loss)	407,942	289,651	148,241
Total Assets	1,239,964	1,181,783	1,144,339
Depreciation and amortization of property	8,480	6,104	5,492
Operating Segments [Member] | Asset Management Segment [Member]
Segment Reporting Information [Line Items]
Net Revenue	1,424,985	1,167,466	1,237,390
Operating Expenses	1,032,825	861,031	887,522
Operating Income (Loss)	392,160	306,435	349,868
Total Assets	1,128,549	958,588	821,641
Depreciation and amortization of property	5,618	3,730	2,995
Corporate [Member]
Segment Reporting Information [Line Items]
Net Revenue	3,554	(21,829)	(24,653)
Operating Expenses	79,808	72,116	80,758
Operating Income (Loss)	(76,254)	(93,945)	(105,411)
Total Assets	4,778,668	3,831,490	3,673,601
Depreciation and amortization of property	$ 24,217	$ 25,261	$ 27,085