Fair Value Measurements - Summary of Gains and Losses (Realized and Unrealized) Relating to Level 3 Assets and Liabilities Included in Earnings (Detail) (Successor [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Net Investment Income [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total gains or losses included in earnings for the period	$ 5,729	$ 419
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held	0	0
Realized Gains Or (Losses) and Other Settlements On Credit Derivative Contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total gains or losses included in earnings for the period	419	775
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held	0	0
Unrealized Gains Or (Losses) On Credit Derivative Contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total gains or losses included in earnings for the period	(2,918)	6,607
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held	(2,942)	6,607
Interest Rate Swaps [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total gains or losses included in earnings for the period	(11,422)	(21,631)
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held	(11,422)	(21,631)
Income Loss On Variable Interest Entities [Member] | Variable Interest Entity [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total gains or losses included in earnings for the period	363,049	186,630
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held	363,049	184,635
Other Income or (Loss) [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total gains or losses included in earnings for the period	(295)	(262)
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held	$ (295)	$ (262)