CONSOLIDATED VARIABLE INTEREST ENTITIES (Details) - CLO - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Variable Interest Entity [Line Items]
Total assets	$ 887,429	$ 884,637
Total liabilities	692,777	690,755
Net equity in VIEs (eliminated in consolidation)	194,653	193,882
Total equity	194,653	193,882
Total liabilities and equity	887,430	884,637
Mortgage loan receivables held for investment, net, at amortized cost
Variable Interest Entity [Line Items]
Total assets	861,209	880,385
Accrued interest receivable
Variable Interest Entity [Line Items]
Total assets	4,360	4,252
Other assets
Variable Interest Entity [Line Items]
Total assets	21,860	0
Senior and unsecured debt obligations
Variable Interest Entity [Line Items]
Total liabilities	691,312	689,961
Accrued expenses
Variable Interest Entity [Line Items]
Total liabilities	1,463	794
Other liabilities
Variable Interest Entity [Line Items]
Total liabilities	$ 2	$ 0