Derivative Instruments - Summary of Location and Amount of Gains and Losses of Derivative Contracts (Detail) - Successor [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative instruments, gain (loss) recognized in income, net, Total	$ (28,482)	$ (188,012)	$ 11,379	$ (423,421)
Net Change in Fair Value of Credit Derivatives [Member] | Credit Derivatives [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative instruments, gain (loss) recognized in income, net, Total	179	1,733	7,855	18,554
Derivative Products [Member] | Interest Rate Swap [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative instruments, gain (loss) recognized in income, net, Total	3,394	(14,646)	40,643	(125,079)
Derivative Products [Member] | Futures Contracts [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative instruments, gain (loss) recognized in income, net, Total	590	136
Derivative Products [Member] | Other Contracts [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative instruments, gain (loss) recognized in income, net, Total			(4,105)	(9,186)
Derivative Products [Member] | ERROR in label resolution.
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative instruments, gain (loss) recognized in income, net, Total	3,984	(14,510)	36,538	(134,265)
Income Loss On Variable Interest Entities [Member] | Variable Interest Entity [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative instruments, gain (loss) recognized in income, net, Total	(32,645)	(175,235)	(33,014)	(307,710)
Income Loss On Variable Interest Entities [Member] | Interest Rate Swap [Member] | Variable Interest Entity [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative instruments, gain (loss) recognized in income, net, Total	(24,851)	(180,744)	(10,321)	(339,524)
Income Loss On Variable Interest Entities [Member] | Currency Swaps [Member] | Variable Interest Entity [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative instruments, gain (loss) recognized in income, net, Total	$ (7,794)	$ 5,509	$ (22,693)	$ 31,814