DEBT OBLIGATIONS AND CREDIT FACILITIES - Debt Obligations of CLOs (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Fair Value		$ 4,127,994
Consolidated Funds
Debt Instrument [Line Items]
Fair Value	$ 4,312,023
Consolidated Funds | Senior secured notes
Debt Instrument [Line Items]
Fair Value	$ 4,146,828	$ 3,976,602
Weighted Average Interest Rate	2.71%	2.69%
Weighted Average Remaining Maturity (years)	10 years	9 years 10 months 24 days
Consolidated Funds | Subordinated note
Debt Instrument [Line Items]
Fair Value	$ 165,195	$ 151,392
Weighted Average Remaining Maturity (years)	8 years 9 months 18 days	9 years 8 months 12 days