FAIR VALUE OPTION - Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Fair Value, Option, Quantitative Disclosures [Line Items]
Assets	$ 25,906,901	$ 23,952,682
Liabilities	16,279,747	14,658,137
Private Equity
Fair Value, Option, Quantitative Disclosures [Line Items]
Assets	0	0
Credit
Fair Value, Option, Quantitative Disclosures [Line Items]
Assets	6,535,237	6,451,765
Investments of Consolidated CFEs
Fair Value, Option, Quantitative Disclosures [Line Items]
Assets	16,647,431	14,948,237
Real Assets
Fair Value, Option, Quantitative Disclosures [Line Items]
Assets	204,664	222,488
Equity Method - Other
Fair Value, Option, Quantitative Disclosures [Line Items]
Assets	2,346,717	1,934,555
Other Investments
Fair Value, Option, Quantitative Disclosures [Line Items]
Assets	172,852	395,637
Debt Obligations of Consolidated CFEs
Fair Value, Option, Quantitative Disclosures [Line Items]
Liabilities	$ 16,279,747	$ 14,658,137