FAIR VALUE - Consolidated Funds Valuation of Investments and Other Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total derivatives	$ 10,435	$ 24,077
Total derivatives	(14,965)	(35,862)
Consolidated Funds
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	4,210,578	3,908,613
Total derivatives	9,743	10,737
Total derivatives	(14,088)	(24,022)
Consolidated Funds | Options and futures
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total derivatives	312	279
Total derivatives	(818)
Consolidated Funds | Level III
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	2,667,194	2,390,273
Consolidated Funds | Fair Value, Measurements, Recurring
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	4,210,578	3,908,613
Total derivatives	9,743	10,737
Total assets	4,220,321	3,919,350
Total derivatives	(14,088)	(24,022)
Total liabilities	(14,088)	(24,022)
Consolidated Funds | Fair Value, Measurements, Recurring | Foreign-currency forward contracts
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total derivatives	1,813	9,758
Total derivatives	(13,232)	(16,356)
Consolidated Funds | Fair Value, Measurements, Recurring | Swaps
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total derivatives	7,618	700
Total derivatives	(38)	(7,666)
Consolidated Funds | Fair Value, Measurements, Recurring | Options and futures
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total derivatives	312	279
Total derivatives	(818)	0
Consolidated Funds | Fair Value, Measurements, Recurring | Corporate debt – bank debt
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	1,387,124	1,114,494
Consolidated Funds | Fair Value, Measurements, Recurring | Corporate debt – all other
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	1,038,046	984,344
Consolidated Funds | Fair Value, Measurements, Recurring | Equities – common stock
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	1,035,500	1,038,449
Consolidated Funds | Fair Value, Measurements, Recurring | Equities – preferred stock
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	664,603	696,855
Consolidated Funds | Fair Value, Measurements, Recurring | Real estate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	85,305	74,471
Consolidated Funds | Fair Value, Measurements, Recurring | Level I
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	274,007	307,113
Total derivatives	7,815	279
Total assets	281,822	307,392
Total derivatives	(818)	(7,666)
Total liabilities	(818)	(7,666)
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
Total derivatives	0	0
Consolidated Funds | Fair Value, Measurements, Recurring | Level I | Swaps
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total derivatives	7,503	0
Total derivatives	0	(7,666)
Consolidated Funds | Fair Value, Measurements, Recurring | Level I | Options and futures
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total derivatives	312	279
Total derivatives	(818)	0
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	192,004	226,862
Consolidated Funds | Fair Value, Measurements, Recurring | Level I | Equities – preferred stock
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	82,003	80,251
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	1,269,377	1,211,227
Total derivatives	1,928	10,458
Total assets	1,271,305	1,221,685
Total derivatives	(13,270)	(16,356)
Total liabilities	(13,270)	(16,356)
Consolidated Funds | Fair Value, Measurements, Recurring | Level II | Foreign-currency forward contracts
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total derivatives	1,813	9,758
Total derivatives	(13,232)	(16,356)
Consolidated Funds | Fair Value, Measurements, Recurring | Level II | Swaps
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total derivatives	115	700
Total derivatives	(38)	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
Total derivatives	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	424,808	411,997
Consolidated Funds | Fair Value, Measurements, Recurring | Level II | Corporate debt – all other
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	810,882	764,841
Consolidated Funds | Fair Value, Measurements, Recurring | Level II | Equities – common stock
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	33,687	34,389
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	2,667,194	2,390,273
Total derivatives	0	0
Total assets	2,667,194	2,390,273
Total derivatives	0	0
Total liabilities	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
Total derivatives	0	0
Consolidated Funds | Fair Value, Measurements, Recurring | Level III | Swaps
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total derivatives	0	0
Total derivatives	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
Total derivatives	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	962,316	702,497
Consolidated Funds | Fair Value, Measurements, Recurring | Level III | Corporate debt – all other
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	227,164	219,503
Consolidated Funds | Fair Value, Measurements, Recurring | Level III | Equities – common stock
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	809,809	777,198
Consolidated Funds | Fair Value, Measurements, Recurring | Level III | Equities – preferred stock
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	582,600	616,604
Consolidated Funds | Fair Value, Measurements, Recurring | Level III | Real estate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total investments	$ 85,305	$ 74,471