Segment Information - Segment's Contribution with Respect to Net Revenue, Operating Expenses, Operating Income (Loss) and Total Assets (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Segment Reporting Information [Line Items]
Net Revenue	$ 694,892	$ 660,107
Operating Expenses	535,164	525,817
Operating Income (Loss)	159,728	134,290
Total Assets	6,848,346		$ 7,147,181
Operating Segments [Member] | Financial Advisory Segment [Member]
Segment Reporting Information [Line Items]
Net Revenue	390,215	318,412
Operating Expenses	298,258	258,047
Operating Income (Loss)	91,957	60,365
Total Assets	1,334,389		1,239,964
Operating Segments [Member] | Asset Management Segment [Member]
Segment Reporting Information [Line Items]
Net Revenue	338,501	347,490
Operating Expenses	241,516	232,103
Operating Income (Loss)	96,985	115,387
Total Assets	951,464		1,128,549
Corporate [Member]
Segment Reporting Information [Line Items]
Net Revenue	(33,824)	(5,795)
Operating Expenses	(4,610)	35,667
Operating Income (Loss)	(29,214)	$ (41,462)
Total Assets	$ 4,562,493		$ 4,778,668