MANAGEMENT AGREEMENT AND RELATED PARTY TRANSACTIONS (Details)	1 Months Ended	3 Months Ended	4 Months Ended	7 Months Ended	8 Months Ended	12 Months Ended
	May. 31, 2014 USD ($)	Sep. 30, 2007 USD ($)	Apr. 30, 2014 USD ($)	Dec. 31, 2014 USD ($) issuer	Dec. 31, 2014 USD ($) issuer	Dec. 31, 2015 USD ($) issuer period $ / shares	Dec. 31, 2014 USD ($) issuer	Dec. 31, 2013 USD ($)	May. 23, 2014 $ / shares
Management Agreement and Related Party Transactions
Distribution to parent						$ 179,100,000
Successor Company
Management Agreement and Related Party Transactions
Related party transaction expense					$ 33,764,000	38,086,000
Distribution to parent	$ 44,900,000			$ 76,200,000	617,080,000	430,829,000
Distributions to parent per unit (in dollars per share) | $ / shares									$ 0.43
Estimated fair value of contributions from parent					474,844,000	$ 251,748,000
Successor Company | CLO management fees | Maximum
Management Agreement and Related Party Transactions
Entity's percentage in subordinated notes						100.00%
Successor Company | CLO management fees | CLO 2013-1 and CLO 2013-2
Management Agreement and Related Party Transactions
Entity's percentage in subordinated notes						100.00%
Successor Company | Manager
Management Agreement and Related Party Transactions
Renewal period (in years)						1 year
Votes for termination, minimum (as a percent)						66.70%
Notice period for termination (in days)						180 days
Multiplier used to determine termination fee						4
Number of 12 month periods considered for calculation of termination fee (in periods) | period						2
Specified period for which average annual incentive fee to be considered (in months)						12 months
Successor Company | Manager | Base Management Fees
Management Agreement and Related Party Transactions
Common share closing price, minimum (in dollars per share) | $ / shares						$ 20.00
Number of consecutive trading days						5 days
Related party transaction expense					15,145,000	$ 9,532,000
Successor Company | Manager | Incentive fees
Management Agreement and Related Party Transactions
Related party transaction expense					0	0
Successor Company | Manager | Manager share-based compensation
Management Agreement and Related Party Transactions
Related party transaction expense					0	0
Successor Company | Manager | Reimbursable General And Administrative Expenses
Management Agreement and Related Party Transactions
Related party transaction expense					3,000,000	5,500,000
Successor Company | Collateral manager | CLO management fees
Management Agreement and Related Party Transactions
Fees, waived					4,200,000	2,000,000
Related party transaction expense					18,619,000	28,554,000
Predecessor Company
Management Agreement and Related Party Transactions
Related party transaction expense			$ 29,841,000					$ 68,576,000
Predecessor Company | Manager | Base Management Fees
Management Agreement and Related Party Transactions
Common shares offering		$ 230,400,000
Common share right offering		$ 270,000,000
Fees, waived			2,900,000					8,800,000
Related party transaction expense			5,253,000					25,029,000
Predecessor Company | Manager | Incentive fees
Management Agreement and Related Party Transactions
Related party transaction expense			12,882,000					22,741,000
Predecessor Company | Manager | Manager share-based compensation
Management Agreement and Related Party Transactions
Related party transaction expense			690,000					3,524,000
Predecessor Company | Manager | Reimbursable General And Administrative Expenses
Management Agreement and Related Party Transactions
Related party transaction expense			2,800,000					9,800,000
Predecessor Company | Collateral manager | CLO management fees
Management Agreement and Related Party Transactions
Fees, waived			1,600,000					19,700,000
Related party transaction expense			11,016,000					17,282,000
Restricted common shares | Predecessor Company
Management Agreement and Related Party Transactions
Share-based compensation			1,018,000					4,559,000
Restricted common shares | Predecessor Company | Manager | Manager share-based compensation
Management Agreement and Related Party Transactions
Share-based compensation			$ 700,000					$ 3,500,000
Affiliated Entity | Successor Company
Management Agreement and Related Party Transactions
Estimated fair value				$ 1,700,000,000	$ 1,700,000,000	$ 734,300,000	$ 1,700,000,000
Investment in affiliates, number of issuers | issuer				19	19	8	19
Percent to total investment in corporate loans, debt securities and other investments | Affiliated Investments | Affiliated Entity | Successor Company
Management Agreement and Related Party Transactions
Concentration risk (as a percent)						11.00%	20.00%
Corporate loans, at estimated fair value | Affiliated Entity | Successor Company
Management Agreement and Related Party Transactions
Estimated fair value						$ 723,300,000
Equity Investments, at Estimated Fair Value | Affiliated Entity | Successor Company
Management Agreement and Related Party Transactions
Estimated fair value				$ 13,600,000	$ 13,600,000	11,000,000	$ 13,600,000
Corporate loans | Affiliated Entity | Successor Company
Management Agreement and Related Party Transactions
Estimated fair value				1,600,000,000	1,600,000,000		1,600,000,000
Corporate Debt Securities | Affiliated Entity | Successor Company
Management Agreement and Related Party Transactions
Estimated fair value				9,500,000	9,500,000		9,500,000
Joint Ventures And Partnerships | Affiliated Entity | Successor Company
Management Agreement and Related Party Transactions
Estimated fair value				$ 618,600,000	$ 618,600,000	$ 805,500,000	$ 618,600,000