INVESTMENTS - Investment Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Schedule of Equity Method Investments [Line Items]
Other investments, at fair value	$ (1,866)	$ 6,693
Total investment income	11,741	113,239
Funds
Schedule of Equity Method Investments [Line Items]
Equity-method investments:	14,253	106,524
Companies
Schedule of Equity Method Investments [Line Items]
Equity-method investments:	$ (646)	$ 22