TRANSACTIONS WITH AFFILIATES AND AFFILIATED ENTITIES - Schedule of Affiliate Transactions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Due to Related Parties [Abstract]
Total	$ 101,471	$ 88,961
Management fees	62,594	55,634	$ 41,610
Incentive compensation	94,900	81,373	42,197
Manager
Due to Related Parties [Abstract]
Management fees	5,779	4,734
Incentive compensation	94,900	81,373
Expense reimbursements and other	792	2,854
Total	101,471	88,961
Management fees	62,594	55,634	41,610
Incentive compensation	94,900	81,373	42,197
Expense reimbursements	500	500	500
Total	$ 157,994	$ 137,507	$ 84,307