FAIR VALUE MEASUREMENTS - Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Assets:
Investments, at fair value	$ 687,507	$ 701,964
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other assets	Other assets
Liabilities:
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other liabilities	Other liabilities
Fair Value, Measurements, Recurring
Assets:
Derivative assets	$ 4,879	$ 2,789
Assets, fair value disclosure	786,369	704,753
Liabilities:
Securities sold, not yet purchased	5,235	4,809
Contingent consideration liability	4,389	6,583
Derivative liabilities	274,033	368,673
Total of liabilities measured at fair value	283,657	380,065
Fair Value, Measurements, Recurring | Debt
Assets:
Investments, at fair value	99,254	4,285
Fair Value, Measurements, Recurring | Equity
Assets:
Investments, at fair value	54,442	54,717
Fair Value, Measurements, Recurring | Alternative investments
Assets:
Investments, at fair value	57,679	61,680
Fair Value, Measurements, Recurring | Debt
Assets:
Investments, at fair value	145,151	191,325
Fair Value, Measurements, Recurring | Equity
Assets:
Investments, at fair value	282,782	343,139
Fair Value, Measurements, Recurring | Private equity
Assets:
Investments, at fair value	48,199	46,818
Fair Value, Measurements, Recurring | U.S. Treasury Securities
Assets:
Deposits with banks and short-term investments (a)	24,488
Fair Value, Measurements, Recurring | U.S. Treasury Securities
Assets:
Cash and cash equivalents	69,495
Fair Value, Measurements, Recurring | Level 1
Assets:
Derivative assets	0	0
Assets, fair value disclosure	669,846	598,186
Liabilities:
Securities sold, not yet purchased	5,235	4,809
Contingent consideration liability	0	0
Derivative liabilities	0	0
Total of liabilities measured at fair value	5,235	4,809
Fair Value, Measurements, Recurring | Level 1 | Debt
Assets:
Investments, at fair value	98,350	4,285
Fair Value, Measurements, Recurring | Level 1 | Equity
Assets:
Investments, at fair value	53,831	54,224
Fair Value, Measurements, Recurring | Level 1 | Alternative investments
Assets:
Investments, at fair value	10,540	15,676
Fair Value, Measurements, Recurring | Level 1 | Debt
Assets:
Investments, at fair value	130,409	180,907
Fair Value, Measurements, Recurring | Level 1 | Equity
Assets:
Investments, at fair value	282,733	343,094
Fair Value, Measurements, Recurring | Level 1 | Private equity
Assets:
Investments, at fair value	0	0
Fair Value, Measurements, Recurring | Level 1 | U.S. Treasury Securities
Assets:
Deposits with banks and short-term investments (a)	24,488
Fair Value, Measurements, Recurring | Level 1 | U.S. Treasury Securities
Assets:
Cash and cash equivalents	69,495
Fair Value, Measurements, Recurring | Level 2
Assets:
Derivative assets	4,879	2,789
Assets, fair value disclosure	20,522	13,202
Liabilities:
Securities sold, not yet purchased	0	0
Contingent consideration liability	0	0
Derivative liabilities	274,033	368,673
Total of liabilities measured at fair value	274,033	368,673
Fair Value, Measurements, Recurring | Level 2 | Debt
Assets:
Investments, at fair value	904	0
Fair Value, Measurements, Recurring | Level 2 | Equity
Assets:
Investments, at fair value	0	0
Fair Value, Measurements, Recurring | Level 2 | Alternative investments
Assets:
Investments, at fair value	0	0
Fair Value, Measurements, Recurring | Level 2 | Debt
Assets:
Investments, at fair value	14,739	10,413
Fair Value, Measurements, Recurring | Level 2 | Equity
Assets:
Investments, at fair value	0	0
Fair Value, Measurements, Recurring | Level 2 | Private equity
Assets:
Investments, at fair value	0	0
Fair Value, Measurements, Recurring | Level 2 | U.S. Treasury Securities
Assets:
Deposits with banks and short-term investments (a)	0
Fair Value, Measurements, Recurring | Level 2 | U.S. Treasury Securities
Assets:
Cash and cash equivalents	0
Fair Value, Measurements, Recurring | Level 3
Assets:
Derivative assets	0	0
Assets, fair value disclosure	875	766
Liabilities:
Securities sold, not yet purchased	0	0
Contingent consideration liability	4,389	6,583
Derivative liabilities	0	0
Total of liabilities measured at fair value	4,389	6,583
Fair Value, Measurements, Recurring | Level 3 | Debt
Assets:
Investments, at fair value	0	0
Fair Value, Measurements, Recurring | Level 3 | Equity
Assets:
Investments, at fair value	611	493
Fair Value, Measurements, Recurring | Level 3 | Alternative investments
Assets:
Investments, at fair value	0	0
Fair Value, Measurements, Recurring | Level 3 | Debt
Assets:
Investments, at fair value	0	0
Fair Value, Measurements, Recurring | Level 3 | Equity
Assets:
Investments, at fair value	0	0
Fair Value, Measurements, Recurring | Level 3 | Private equity
Assets:
Investments, at fair value	264	273
Fair Value, Measurements, Recurring | Level 3 | U.S. Treasury Securities
Assets:
Deposits with banks and short-term investments (a)	0
Fair Value, Measurements, Recurring | Level 3 | U.S. Treasury Securities
Assets:
Cash and cash equivalents	0
Fair Value, Measurements, Recurring | NAV
Assets:
Derivative assets	0	0
Assets, fair value disclosure	95,126	92,599
Liabilities:
Securities sold, not yet purchased	0	0
Contingent consideration liability	0	0
Derivative liabilities	0	0
Total of liabilities measured at fair value	0	0
Fair Value, Measurements, Recurring | NAV | Debt
Assets:
Investments, at fair value	0	0
Fair Value, Measurements, Recurring | NAV | Equity
Assets:
Investments, at fair value	0	0
Fair Value, Measurements, Recurring | NAV | Alternative investments
Assets:
Investments, at fair value	47,139	46,004
Fair Value, Measurements, Recurring | NAV | Debt
Assets:
Investments, at fair value	3	5
Fair Value, Measurements, Recurring | NAV | Equity
Assets:
Investments, at fair value	49	45
Fair Value, Measurements, Recurring | NAV | Private equity
Assets:
Investments, at fair value	47,935	$ 46,545
Fair Value, Measurements, Recurring | NAV | U.S. Treasury Securities
Assets:
Deposits with banks and short-term investments (a)	0
Fair Value, Measurements, Recurring | NAV | U.S. Treasury Securities
Assets:
Cash and cash equivalents	$ 0