INVESTMENT OPERATIONS - Schedule of Fair Value (Proceeds) and Gains/Losses Realized on Securities Sold in an Unrealized Gain/Loss Position (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		5 Months Ended	6 Months Ended
	Jan. 31, 2015	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2015	Jun. 30, 2016
Successor
Investment [Line Items]
Fair value (proceeds) of securities in an unrealized gain position sold		$ 513,544	$ 432,158	$ 715,038	$ 822,793
Gain realized on the sale of securities in an unrealized gain position		18,752	5,435	6,942	27,800
Fair value (proceeds) of securities in an unrealized loss position sold		6,895	28,644	49,326	60,582
Loss realized on the sale of securities in an unrealized loss position		$ (1,820)	$ (2,075)	$ (3,209)	$ (5,313)
Predecessor
Investment [Line Items]
Fair value (proceeds) of securities in an unrealized gain position sold	$ 172,551
Gain realized on the sale of securities in an unrealized gain position	6,920
Fair value (proceeds) of securities in an unrealized loss position sold	435
Loss realized on the sale of securities in an unrealized loss position	$ (29)