FAIR VALUE MEASUREMENTS - Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	$ 670,474	$ 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	$ 2,359	$ 2,789
Assets, fair value disclosure	817,917	704,753
Securities sold, not yet purchased	5,041	4,809
Contingent consideration liability	4,442	6,583
Derivative liabilities	293,023	368,673
Total of liabilities measured at fair value	302,506	380,065
Fair Value, Measurements, Recurring | Debt
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	51,101	4,285
Fair Value, Measurements, Recurring | Equity
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	57,798	54,717
Fair Value, Measurements, Recurring | Alternative investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	59,558	61,680
Fair Value, Measurements, Recurring | Debt
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	150,924	191,325
Fair Value, Measurements, Recurring | Equity
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	304,736	343,139
Fair Value, Measurements, Recurring | Private equity
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	46,357	46,818
Fair Value, Measurements, Recurring | U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Deposits with banks and short-term investments	24,631
Fair Value, Measurements, Recurring | U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash and cash equivalents	120,453
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Derivative assets	0	0
Assets, fair value disclosure	703,099	598,186
Securities sold, not yet purchased	5,041	4,809
Contingent consideration liability	0	0
Derivative liabilities	0	0
Total of liabilities measured at fair value	5,041	4,809
Fair Value, Measurements, Recurring | Level 1 | Debt
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	49,673	4,285
Fair Value, Measurements, Recurring | Level 1 | Equity
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	57,148	54,224
Fair Value, Measurements, Recurring | Level 1 | Alternative investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	11,078	15,676
Fair Value, Measurements, Recurring | Level 1 | Debt
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	135,629	180,907
Fair Value, Measurements, Recurring | Level 1 | Equity
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	304,487	343,094
Fair Value, Measurements, Recurring | Level 1 | Private equity
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	0	0
Fair Value, Measurements, Recurring | Level 1 | U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Deposits with banks and short-term investments	24,631
Fair Value, Measurements, Recurring | Level 1 | U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash and cash equivalents	120,453
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Derivative assets	2,359	2,789
Assets, fair value disclosure	19,275	13,202
Securities sold, not yet purchased	0	0
Contingent consideration liability	0	0
Derivative liabilities	293,023	368,673
Total of liabilities measured at fair value	293,023	368,673
Fair Value, Measurements, Recurring | Level 2 | Debt
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	1,428	0
Fair Value, Measurements, Recurring | Level 2 | Equity
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	0	0
Fair Value, Measurements, Recurring | Level 2 | Alternative investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	0	0
Fair Value, Measurements, Recurring | Level 2 | Debt
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	15,292	10,413
Fair Value, Measurements, Recurring | Level 2 | Equity
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	196	0
Fair Value, Measurements, Recurring | Level 2 | Private equity
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	0	0
Fair Value, Measurements, Recurring | Level 2 | U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Deposits with banks and short-term investments	0
Fair Value, Measurements, Recurring | Level 2 | U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash and cash equivalents	0
Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Derivative assets	0	0
Assets, fair value disclosure	926	766
Securities sold, not yet purchased	0	0
Contingent consideration liability	4,442	6,583
Derivative liabilities	0	0
Total of liabilities measured at fair value	4,442	6,583
Fair Value, Measurements, Recurring | Level 3 | Debt
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	0	0
Fair Value, Measurements, Recurring | Level 3 | Equity
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	650	493
Fair Value, Measurements, Recurring | Level 3 | Alternative investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	0	0
Fair Value, Measurements, Recurring | Level 3 | Debt
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	0	0
Fair Value, Measurements, Recurring | Level 3 | Equity
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	0	0
Fair Value, Measurements, Recurring | Level 3 | Private equity
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	276	273
Fair Value, Measurements, Recurring | Level 3 | U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Deposits with banks and short-term investments	0
Fair Value, Measurements, Recurring | Level 3 | U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash and cash equivalents	0
Fair Value, Measurements, Recurring | NAV
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Derivative assets	0	0
Assets, fair value disclosure	94,617	92,599
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
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	0	0
Fair Value, Measurements, Recurring | NAV | Equity
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	0	0
Fair Value, Measurements, Recurring | NAV | Alternative investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	48,480	46,004
Fair Value, Measurements, Recurring | NAV | Debt
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	3	5
Fair Value, Measurements, Recurring | NAV | Equity
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	53	45
Fair Value, Measurements, Recurring | NAV | Private equity
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	46,081	$ 46,545
Fair Value, Measurements, Recurring | NAV | U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Deposits with banks and short-term investments	0
Fair Value, Measurements, Recurring | NAV | U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash and cash equivalents	$ 0