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Derivative Instruments - Summary of Location and Amount of Gains and Losses of Derivative Contracts (Detail) - Successor [Member] - USD ($) $ in Thousands | 12 Months Ended
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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

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- Definition Amount of increase (decrease) in the fair value of derivatives recognized in the income statement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5618551-113959 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (a),(c),(d),(e) -URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959 + Details
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