RELATED PARTY TRANSACTION - Related Party Costs Incurred (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Related Party Transaction [Line Items]
Payable	$ 2,625		$ 2,625		$ 2,699
Continuing Operations | ACREM
Related Party Transaction [Line Items]
Incurred	2,631	$ 2,155	5,451	$ 4,750
Payable	2,625		2,625		2,699
Continuing Operations | ACREM | Management fees
Related Party Transaction [Line Items]
Incurred	1,541	1,338	3,085	2,690
Payable	1,541		1,541		1,549
Continuing Operations | ACREM | Incentive fees
Related Party Transaction [Line Items]
Incurred	113	0	381	0
Payable	113		113		27
Continuing Operations | ACREM | General and administrative expenses
Related Party Transaction [Line Items]
Incurred	949	660	1,897	1,557
Payable	949		949		1,024
Continuing Operations | ACREM | Direct costs
Related Party Transaction [Line Items]
Incurred	28	157	88	503
Payable	$ 22		$ 22		$ 99
General and administrative expenses | Continuing Operations | ACREM | Direct costs
Related Party Transaction [Line Items]
Incurred		108		261
Interest Expense | Continuing Operations | ACREM | Direct costs
Related Party Transaction [Line Items]
Incurred		$ 49		$ 242