SEGMENT INFORMATION - Select Financial Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Segment Reporting Information [Line Items]
Net Revenue	$ 648,051	$ 764,753
Adjusted Compensation and Benefits Expense	421,286	492,733
Adjusted Non-compensation Expense	147,882	134,293
Other Segment Items	(4,866)	(18,188)
Adjusted Operating Income (Loss)	74,017	119,539
Interest income (included in net revenue)	11,662	11,471
Depreciation and amortization of property (included in adjusted non-compensation expense)	8,431	9,089
Financial Advisory
Segment Reporting Information [Line Items]
Net Revenue	367,359	453,507
Adjusted Compensation and Benefits Expense	239,968	302,080
Adjusted Non-compensation Expense	52,561	47,865
Other Segment Items	2,184	(6,873)
Adjusted Operating Income (Loss)	77,014	96,689
Interest income (included in net revenue)	1,197	966
Depreciation and amortization of property (included in adjusted non-compensation expense)	2,010	2,249
Asset Management
Segment Reporting Information [Line Items]
Net Revenue	288,100	295,476
Adjusted Compensation and Benefits Expense	142,827	150,698
Adjusted Non-compensation Expense	59,211	55,575
Other Segment Items	(23,606)	(19,542)
Adjusted Operating Income (Loss)	62,456	69,661
Interest income (included in net revenue)	2,447	3,711
Depreciation and amortization of property (included in adjusted non-compensation expense)	1,381	1,289
Corporate
Segment Reporting Information [Line Items]
Net Revenue	(7,408)	15,770
Adjusted Compensation and Benefits Expense	38,491	39,955
Adjusted Non-compensation Expense	36,110	30,853
Other Segment Items	16,556	8,227
Adjusted Operating Income (Loss)	(65,453)	(46,811)
Interest income (included in net revenue)	8,018	6,794
Depreciation and amortization of property (included in adjusted non-compensation expense)	$ 5,040	$ 5,551