Derivative Instruments - Summary of Notional for VIE Derivatives Outstanding (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Derivative products, Notional Amount	$ 2,491,138	$ 2,776,103
Derivative products, Notional Amount	87,715	94,322
Successor Ambac [Member]
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Derivative products, Notional Amount	2,491,138	2,776,103
Variable Interest Entity, Primary Beneficiary [Member] | Successor Ambac [Member] | Interest Rate Swaps [Member]
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Derivative products, Notional Amount	1,829,642	1,818,118
Variable Interest Entity, Primary Beneficiary [Member] | Successor Ambac [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	3,371,951	3,350,714
Variable Interest Entity, Primary Beneficiary [Member] | Successor Ambac [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	775,202	770,319
Variable Interest Entity, Primary Beneficiary [Member] | Successor Ambac [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	$ 19,553	$ 20,130