CONSOLIDATED VARIABLE INTEREST ENTITIES (Details) - CLO $ in Thousands	Dec. 31, 2017 USD ($)
Variable Interest Entity [Line Items]
Total assets	$ 884,637
Total liabilities	690,755
Net equity in VIEs (eliminated in consolidation)	193,882
Total equity	193,882
Total liabilities and equity	884,637
Mortgage loan receivables held for investment, net, at amortized cost
Variable Interest Entity [Line Items]
Total assets	880,385
Accrued interest receivable
Variable Interest Entity [Line Items]
Total assets	4,252
Senior and unsecured debt obligations
Variable Interest Entity [Line Items]
Total liabilities	689,961
Accrued expenses
Variable Interest Entity [Line Items]
Total liabilities	$ 794