CONSOLIDATED VARIABLE INTEREST ENTITIES (Details) - CLO - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Variable Interest Entity [Line Items]
Total assets	$ 427,781	$ 795,813
Total liabilities	263,983	608,913
Net equity in VIEs (eliminated in consolidation)	163,798	186,900
Total equity	163,798	186,900
Total liabilities and equity	427,781	795,813
Mortgage loan receivables held for investment, net, at amortized cost
Variable Interest Entity [Line Items]
Total assets	425,439	710,502
Accrued interest receivable
Variable Interest Entity [Line Items]
Total assets	2,342	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	263,215	607,440
Accrued expenses
Variable Interest Entity [Line Items]
Total liabilities	766	1,471
Other liabilities
Variable Interest Entity [Line Items]
Total liabilities	$ 2	$ 2