Derivative Instruments - Summarize Information by Major Category of CDS Contracts (Detail) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2016 USD ($) Transactions	Dec. 31, 2015 USD ($) Transactions
Summary of information by major category of CDS contracts
Gross principal notional outstanding	$ 933,064	$ 970,883
Successor [Member]
Summary of information by major category of CDS contracts
Number of CDS transactions | Transactions	11	14
Derivative, Average Remaining Maturity	4 years 5 months	4 years 3 months
Gross principal notional outstanding	$ 933,064	$ 970,883
Successor [Member] | Credit Derivatives [Member]
Summary of information by major category of CDS contracts
Net derivative liabilities at fair value	$ 21,929	$ 34,543
CLO [Member] | Successor [Member]
Summary of information by major category of CDS contracts
Number of CDS transactions | Transactions	5	5
Derivative, Average Remaining Maturity	11 months	1 year 1 month
Gross principal notional outstanding	$ 284,411	$ 295,254
CLO [Member] | Successor [Member] | Credit Derivatives [Member]
Summary of information by major category of CDS contracts
Net derivative liabilities at fair value	$ 1,064	$ 1,837
Other [Member] | Successor [Member]
Summary of information by major category of CDS contracts
Number of CDS transactions | Transactions	6	9
Derivative, Average Remaining Maturity	5 years 11 months	5 years 7 months
Gross principal notional outstanding	$ 648,653	$ 675,629
Other [Member] | Successor [Member] | Credit Derivatives [Member]
Summary of information by major category of CDS contracts
Net derivative liabilities at fair value	$ 20,865	$ 32,706