FAIR VALUE - Consolidated Funds Valuation of Investments and Other Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total derivatives	$ 11,214	$ 17,741
Liabilities	(20,603)	(30,750)
Consolidated Funds
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	5,771,776	5,143,677
Total derivatives	9,308	9,133
Total assets	600,000	0
CLO debt obligations	(381,666)	0
Liabilities	(18,961)	(22,230)
Consolidated Funds | Options and futures
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total derivatives	6	0
Liabilities	(2,714)	(571)
Consolidated Funds | Level III
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	3,675,138	3,603,942
Consolidated Funds | Fair Value, Measurements, Recurring
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	5,771,776	5,143,677
Total derivatives	9,308	9,133
Total assets	5,781,084	5,152,810
Liabilities	(18,961)	(22,230)
Total liabilities	(400,627)	(22,230)
Consolidated Funds | Fair Value, Measurements, Recurring | CLO debt obligations:
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
CLO debt obligations	(381,666)	0
Consolidated Funds | Fair Value, Measurements, Recurring | Secured borrowings | CLO debt obligations:
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
CLO debt obligations	(381,666)	0
Consolidated Funds | Fair Value, Measurements, Recurring | Foreign-currency forward contracts
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total derivatives	1,591	475
Liabilities	(16,218)	(21,659)
Consolidated Funds | Fair Value, Measurements, Recurring | Swaps
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total derivatives	7,711	8,658
Liabilities	(29)	0
Consolidated Funds | Fair Value, Measurements, Recurring | Options and futures
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total derivatives	6	0
Liabilities	(2,714)	(571)
Consolidated Funds | Fair Value, Measurements, Recurring | Corporate debt – bank debt
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	3,126,566	2,363,503
Consolidated Funds | Fair Value, Measurements, Recurring | Corporate debt – all other
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	719,829	959,055
Consolidated Funds | Fair Value, Measurements, Recurring | Equities – common stock
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	1,130,162	1,044,201
Consolidated Funds | Fair Value, Measurements, Recurring | Equities – preferred stock
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	608,538	601,565
Consolidated Funds | Fair Value, Measurements, Recurring | Real estate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	186,681	175,353
Consolidated Funds | Fair Value, Measurements, Recurring | Level I
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	186,008	167,578
Total derivatives	7,717	8,658
Total assets	193,725	176,236
Liabilities	(2,714)	(571)
Total liabilities	(2,714)	(571)
Consolidated Funds | Fair Value, Measurements, Recurring | Level I | CLO debt obligations:
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
CLO debt obligations	0	0
Consolidated Funds | Fair Value, Measurements, Recurring | Level I | Secured borrowings | CLO debt obligations:
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
CLO debt obligations	0	0
Consolidated Funds | Fair Value, Measurements, Recurring | Level I | Foreign-currency forward contracts
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total derivatives	0	0
Liabilities	0	0
Consolidated Funds | Fair Value, Measurements, Recurring | Level I | Swaps
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total derivatives	7,711	8,658
Liabilities	0	0
Consolidated Funds | Fair Value, Measurements, Recurring | Level I | Options and futures
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total derivatives	6	0
Liabilities	(2,714)	(571)
Consolidated Funds | Fair Value, Measurements, Recurring | Level I | Corporate debt – bank debt
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	0	0
Consolidated Funds | Fair Value, Measurements, Recurring | Level I | Corporate debt – all other
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	0	0
Consolidated Funds | Fair Value, Measurements, Recurring | Level I | Equities – common stock
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	183,341	165,649
Consolidated Funds | Fair Value, Measurements, Recurring | Level I | Equities – preferred stock
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	2,667	1,929
Consolidated Funds | Fair Value, Measurements, Recurring | Level I | Real estate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	0	0
Consolidated Funds | Fair Value, Measurements, Recurring | Level II
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	1,910,630	1,372,157
Total derivatives	1,591	475
Total assets	1,912,221	1,372,632
Liabilities	(16,247)	(21,659)
Total liabilities	(397,913)	(21,659)
Consolidated Funds | Fair Value, Measurements, Recurring | Level II | CLO debt obligations:
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
CLO debt obligations	(381,666)	0
Consolidated Funds | Fair Value, Measurements, Recurring | Level II | Secured borrowings | CLO debt obligations:
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
CLO debt obligations	(381,666)	0
Consolidated Funds | Fair Value, Measurements, Recurring | Level II | Foreign-currency forward contracts
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total derivatives	1,591	475
Liabilities	(16,218)	(21,659)
Consolidated Funds | Fair Value, Measurements, Recurring | Level II | Swaps
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total derivatives	0	0
Liabilities	(29)	0
Consolidated Funds | Fair Value, Measurements, Recurring | Level II | Options and futures
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total derivatives	0	0
Liabilities	0	0
Consolidated Funds | Fair Value, Measurements, Recurring | Level II | Corporate debt – bank debt
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	1,367,064	641,615
Consolidated Funds | Fair Value, Measurements, Recurring | Level II | Corporate debt – all other
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	543,566	698,763
Consolidated Funds | Fair Value, Measurements, Recurring | Level II | Equities – common stock
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	0	31,779
Consolidated Funds | Fair Value, Measurements, Recurring | Level II | Equities – preferred stock
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	0	0
Consolidated Funds | Fair Value, Measurements, Recurring | Level II | Real estate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	0	0
Consolidated Funds | Fair Value, Measurements, Recurring | Level III
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	3,675,138	3,603,942
Total derivatives	0	0
Total assets	3,675,138	3,603,942
Liabilities	0	0
Total liabilities	0	0
Consolidated Funds | Fair Value, Measurements, Recurring | Level III | CLO debt obligations:
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
CLO debt obligations	0	0
Consolidated Funds | Fair Value, Measurements, Recurring | Level III | Secured borrowings | CLO debt obligations:
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
CLO debt obligations	0	0
Consolidated Funds | Fair Value, Measurements, Recurring | Level III | Foreign-currency forward contracts
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total derivatives	0	0
Liabilities	0	0
Consolidated Funds | Fair Value, Measurements, Recurring | Level III | Swaps
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total derivatives	0	0
Liabilities	0	0
Consolidated Funds | Fair Value, Measurements, Recurring | Level III | Options and futures
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total derivatives	0	0
Liabilities	0	0
Consolidated Funds | Fair Value, Measurements, Recurring | Level III | Corporate debt – bank debt
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	1,759,502	1,721,888
Consolidated Funds | Fair Value, Measurements, Recurring | Level III | Corporate debt – all other
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	176,263	260,292
Consolidated Funds | Fair Value, Measurements, Recurring | Level III | Equities – common stock
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	946,821	846,773
Consolidated Funds | Fair Value, Measurements, Recurring | Level III | Equities – preferred stock
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	605,871	599,636
Consolidated Funds | Fair Value, Measurements, Recurring | Level III | Real estate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	$ 186,681	$ 175,353