FAIR VALUE - Changes in Fair Value (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 25,624	$ 0	$ 25,750	$ 0
Net gain (loss) included in earnings	957	0	831	0
Ending balance	26,581	0	26,581	0
Net change in unrealized appreciation (depreciation) attributable to assets still held at end of period	957	0	831	0
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	(27,884)	(28,052)	(28,494)	(27,245)
Net gain (loss) included in earnings	2,889	(694)	3,499	(1,501)
Ending balance	(24,995)	(28,746)	(24,995)	(28,746)
Net change in unrealized gains (losses) attributable to financial instruments still held at end of period	$ 2,889	$ (694)	$ 3,499	$ (1,501)