DEBT OBLIGATIONS AND CREDIT FACILITIES - Debt Obligations of CLOs (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Fair Value		$ 3,054,210
Consolidated Funds
Debt Instrument [Line Items]
Fair Value	$ 3,151,113
Consolidated Funds | Senior secured notes
Debt Instrument [Line Items]
Fair Value	$ 3,040,449	$ 2,953,880
Weighted Average Interest Rate	2.49%	2.52%
Weighted Average Remaining Maturity (years)	11 years 1 month 6 days	10 years 8 months 12 days
Consolidated Funds | Subordinated note
Debt Instrument [Line Items]
Fair Value	$ 110,664	$ 100,330
Weighted Average Remaining Maturity (years)	11 years	11 years 7 months 6 days