RELATED PARTY TRANSACTIONS AND INTERESTS IN CONSOLIDATED ENTITIES - Due from and Due to Affiliates (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Due from Related Parties:
Total Due from Related Parties	$ 487,453	$ 415,069
Due to Related Parties:
Total Due to Related Parties	712,186	501,387
Due to Managing Partners and Contributing Partners
Due to Related Parties:
Total Due to Related Parties	316,387	302,050
Due from/to credit funds
Due from Related Parties:
Total Due from Related Parties	172,570	186,495
Due to Related Parties:
Total Due to Related Parties	8,375	7,213
Due from/to private equity funds
Due from Related Parties:
Total Due from Related Parties	34,926	27,724
Due to Related Parties:
Total Due to Related Parties	349,483	191,620
Due from/to real assets funds
Due from Related Parties:
Total Due from Related Parties	29,749	26,626
Due to Related Parties:
Total Due to Related Parties	37,941	504
Due from portfolio companies
Due from Related Parties:
Total Due from Related Parties	49,826	53,394
Due from Contributing Partners, employees and former employees
Due from Related Parties:
Total Due from Related Parties	$ 200,382	$ 120,830