FAIR VALUE MEASUREMENTS - Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments, at fair value	$ 620,615	$ 701,964
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other assets	Other assets
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other liabilities	Other liabilities
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Derivative assets	$ 3,257	$ 2,789
Assets, fair value disclosure	788,461	704,753
Securities sold, not yet purchased	6,166	4,809
Contingent consideration liability	4,336	6,583
Derivative liabilities	286,036	368,673
Total of liabilities measured at fair value	296,538	380,065
Fair Value, Measurements, Recurring | Debt
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments, at fair value	546	4,285
Fair Value, Measurements, Recurring | Equity
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments, at fair value	59,148	54,717
Fair Value, Measurements, Recurring | Alternative investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments, at fair value	59,418	61,680
Fair Value, Measurements, Recurring | Debt
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments, at fair value	156,269	191,325
Fair Value, Measurements, Recurring | Equity
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments, at fair value	297,877	343,139
Fair Value, Measurements, Recurring | Private equity
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments, at fair value	47,357	46,818
Fair Value, Measurements, Recurring | U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash and cash qquivalents	164,589
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Assets, fair value disclosure	638,902	598,186
Securities sold, not yet purchased	6,166	4,809
Total of liabilities measured at fair value	6,166	4,809
Fair Value, Measurements, Recurring | Level 1 | Debt
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments, at fair value	0	4,285
Fair Value, Measurements, Recurring | Level 1 | Equity
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments, at fair value	58,673	54,224
Fair Value, Measurements, Recurring | Level 1 | Alternative investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments, at fair value	12,263	15,676
Fair Value, Measurements, Recurring | Level 1 | Debt
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments, at fair value	140,310	180,907
Fair Value, Measurements, Recurring | Level 1 | Equity
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments, at fair value	263,067	343,094
Fair Value, Measurements, Recurring | Level 1 | U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash and cash qquivalents	164,589
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Derivative assets	3,257	2,789
Assets, fair value disclosure	54,518	13,202
Derivative liabilities	286,036	368,673
Total of liabilities measured at fair value	286,036	368,673
Fair Value, Measurements, Recurring | Level 2 | Debt
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments, at fair value	546
Fair Value, Measurements, Recurring | Level 2 | Debt
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments, at fair value	15,954	10,413
Fair Value, Measurements, Recurring | Level 2 | Equity
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments, at fair value	34,761
Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Assets, fair value disclosure	742	766
Contingent consideration liability	4,336	6,583
Total of liabilities measured at fair value	4,336	6,583
Fair Value, Measurements, Recurring | Level 3 | Equity
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments, at fair value	475	493
Fair Value, Measurements, Recurring | Level 3 | Private equity
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments, at fair value	267	273
Fair Value, Measurements, Recurring | NAV
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Assets, fair value disclosure	94,299	92,599
Fair Value, Measurements, Recurring | NAV | Alternative investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments, at fair value	47,155	46,004
Fair Value, Measurements, Recurring | NAV | Debt
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments, at fair value	5	5
Fair Value, Measurements, Recurring | NAV | Equity
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments, at fair value	49	45
Fair Value, Measurements, Recurring | NAV | Private equity
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments, at fair value	$ 47,090	$ 46,545