Derivative Instruments - Summary of Location and Amount of Gains and Losses of Derivative Contracts (Detail) - Successor [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ (76,257)	$ (545,731)	$ 270,917
Net Change in Fair Value of Credit Derivatives [Member] | Credit Derivatives [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative, Gain (Loss) on Derivative, Net	16,372	20,106	41,701
Derivative Products [Member] | Interest Rate Swaps [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative, Gain (Loss) on Derivative, Net	48,870	(50,082)	(41,177)
Derivative Products [Member] | Futures Contracts [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative, Gain (Loss) on Derivative, Net	10,695	(191)	(1,367)
Derivative Products [Member] | Financial Services Derivatives Products [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative, Gain (Loss) on Derivative, Net	59,565	(50,273)	(42,544)
Income Loss On Variable Interest Entities [Member] | Variable Interest Entity [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(152,194)	(515,564)	271,760
Income Loss On Variable Interest Entities [Member] | Interest Rate Swaps [Member] | Variable Interest Entity [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(126,664)	(574,554)	168,003
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, Gain (Loss) on Derivative, Net	$ (25,530)	$ 58,990	$ 103,757