Derivative Instruments - Summary of Notional for VIE Derivatives Outstanding (Detail) - Successor [Member] - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Derivative products, Notional Amount	$ 722,492	$ 737,380
Variable Interest Entity, Primary Beneficiary [Member] | Interest Rate Swap [Member]
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Derivative products, Notional Amount	1,375,936	1,352,010
Variable Interest Entity, Primary Beneficiary [Member] | Interest Rate Swaps-Pay-Fixed/Receive-Variable [Member]
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Derivative products, Notional Amount	2,331,384	2,300,584
Variable Interest Entity, Primary Beneficiary [Member] | Currency Swaps [Member]
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Derivative products, Notional Amount	307,319	312,357
Variable Interest Entity, Primary Beneficiary [Member] | Credit Derivatives [Member]
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Derivative products, Notional Amount	$ 11,686	$ 12,059