CONSOLIDATED VARIABLE INTEREST ENTITIES (Details) - CLO - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Variable Interest Entity [Line Items]
Total assets	$ 275,512	$ 795,813
Total liabilities	118,068	608,913
Net equity in VIEs (eliminated in consolidation)	157,444	186,900
Total equity	157,444	186,900
Total liabilities and equity	275,512	795,813
Total mortgage loan receivables held for investment, net, at amortized cost
Variable Interest Entity [Line Items]
Total assets	274,149	710,502
Accrued interest receivable
Variable Interest Entity [Line Items]
Total assets	1,363	3,921
Other assets
Variable Interest Entity [Line Items]
Total assets	0	81,390
Senior and unsecured debt obligations
Variable Interest Entity [Line Items]
Total liabilities	117,760	607,440
Accrued expenses
Variable Interest Entity [Line Items]
Total liabilities	306	1,471
Other liabilities
Variable Interest Entity [Line Items]
Total liabilities	$ 2	$ 2