Derivative Instruments - Summary of Notional for VIE Derivatives Outstanding (Detail) - Successor [Member] - USD ($) $ in Thousands	Jun. 30, 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	$ 455,792	$ 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	1,428,396	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	2,409,852	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	393,350	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	$ 12,132	$ 12,059