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FAIR VALUE MEASUREMENTS - Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Thousands | Sep. 30, 2023 | Dec. 31, 2022
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Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Investments, at fair value | $ 657,880 | $ 683,496
Assets, fair value disclosure |  | $ 698,050
Derivative Asset, Statement of Financial Position [Extensible Enumeration] | Other assets | Other assets
Fair Value, Measurements, Recurring |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Derivative assets | $ 3,678 | $ 14,554
Assets, fair value disclosure | 661,558 |
Securities sold, not yet purchased | 1,724 | 4,651
Contingent consideration liability | 6,503 |
Derivative liabilities | 342,483 | 327,160
Total of liabilities measured at fair value | 350,710 | 331,811
Fair Value, Measurements, Recurring | Debt |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Investments, at fair value | 4,481 |
Fair Value, Measurements, Recurring | Equities |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Investments, at fair value | 40,659 | 43,889
Fair Value, Measurements, Recurring | Alternative investments |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Investments, at fair value | 60,210 | 56,947
Fair Value, Measurements, Recurring | Debt |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Investments, at fair value | 183,790 | 178,556
Fair Value, Measurements, Recurring | Equity |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Investments, at fair value | 324,239 | 350,282
Fair Value, Measurements, Recurring | Private equity |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Investments, at fair value | 44,501 | 53,822
Fair Value, Measurements, Recurring | Level 1 |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Assets, fair value disclosure | 556,920 | 599,110
Securities sold, not yet purchased | 1,724 | 4,651
Derivative liabilities |  | 115
Total of liabilities measured at fair value | 1,724 | 4,766
Fair Value, Measurements, Recurring | Level 1 | Debt |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Investments, at fair value | 3,524 |
Fair Value, Measurements, Recurring | Level 1 | Equities |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Investments, at fair value | 40,119 | 43,243
Fair Value, Measurements, Recurring | Level 1 | Alternative investments |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Investments, at fair value | 15,534 | 27,073
Fair Value, Measurements, Recurring | Level 1 | Debt |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Investments, at fair value | 173,546 | 178,552
Fair Value, Measurements, Recurring | Level 1 | Equity |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Investments, at fair value | 324,197 | 350,242
Fair Value, Measurements, Recurring | Level 2 |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Derivative assets | 3,678 | 14,554
Assets, fair value disclosure | 14,875 | 14,554
Derivative liabilities | 342,483 | 327,045
Total of liabilities measured at fair value | 342,483 | 327,045
Fair Value, Measurements, Recurring | Level 2 | Debt |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Investments, at fair value | 957 |
Fair Value, Measurements, Recurring | Level 2 | Debt |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Investments, at fair value | 10,240 |
Fair Value, Measurements, Recurring | Level 3 |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Assets, fair value disclosure | 801 | 19,418
Contingent consideration liability | 6,503 |
Total of liabilities measured at fair value | 6,503 |
Fair Value, Measurements, Recurring | Level 3 | Equities |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Investments, at fair value | 540 | 646
Fair Value, Measurements, Recurring | Level 3 | Private equity |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Investments, at fair value | 261 | 18,772
Fair Value, Measurements, Recurring | NAV |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Assets, fair value disclosure | 88,962 | 64,968
Fair Value, Measurements, Recurring | NAV | Alternative investments |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Investments, at fair value | 44,676 | 29,874
Fair Value, Measurements, Recurring | NAV | Debt |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Investments, at fair value | 4 | 4
Fair Value, Measurements, Recurring | NAV | Equity |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Investments, at fair value | 42 | 40
Fair Value, Measurements, Recurring | NAV | Private equity |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Investments, at fair value | $ 44,240 | $ 35,050

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