Derivative Instruments - Summary of Location and Amount of Gains and Losses of Derivative Contracts (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014 Successor Ambac [Member]	Mar. 31, 2014 Successor Ambac [Member] Variable Interest Entity [Member]	Mar. 31, 2014 Successor Ambac [Member] Financial Services Derivatives Products [Member]	Mar. 31, 2014 Successor Ambac [Member] Credit Derivatives [Member] Financial Guarantee [Member] Net Change in Fair Value of Credit Derivatives [Member]	Mar. 31, 2014 Successor Ambac [Member] Interest Rate Swaps [Member] Income on Variable Interest Entities [Member] Variable Interest Entity [Member]	Mar. 31, 2014 Successor Ambac [Member] Interest Rate Swaps [Member] Financial Services Derivatives Products [Member] Derivative Products [Member]	Mar. 31, 2014 Successor Ambac [Member] Currency Swaps [Member] Income on Variable Interest Entities [Member] Variable Interest Entity [Member]	Mar. 31, 2014 Successor Ambac [Member] Futures Contracts [Member] Financial Services Derivatives Products [Member] Derivative Products [Member]	Mar. 31, 2014 Successor Ambac [Member] Other Contracts [Member] Financial Services Derivatives Products [Member] Derivative Products [Member]	Mar. 31, 2013 Predecessor Ambac [Member]	Mar. 31, 2013 Predecessor Ambac [Member] Variable Interest Entity [Member]	Mar. 31, 2013 Predecessor Ambac [Member] Financial Services Derivatives Products [Member]	Mar. 31, 2013 Predecessor Ambac [Member] Credit Derivatives [Member] Financial Guarantee [Member] Net Change in Fair Value of Credit Derivatives [Member]	Mar. 31, 2013 Predecessor Ambac [Member] Interest Rate Swaps [Member] Income on Variable Interest Entities [Member] Variable Interest Entity [Member]	Mar. 31, 2013 Predecessor Ambac [Member] Interest Rate Swaps [Member] Financial Services Derivatives Products [Member] Derivative Products [Member]	Mar. 31, 2013 Predecessor Ambac [Member] Currency Swaps [Member] Income on Variable Interest Entities [Member] Variable Interest Entity [Member]	Mar. 31, 2013 Predecessor Ambac [Member] Futures Contracts [Member] Financial Services Derivatives Products [Member] Derivative Products [Member]	Mar. 31, 2013 Predecessor Ambac [Member] Other Contracts [Member] Financial Services Derivatives Products [Member] Derivative Products [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative instruments, gain (loss) recognized in income, net, Total	$ (118,843)	$ (72,384)	$ (53,841)	$ 7,382	$ (77,792)	$ (51,860)	$ 5,408	$ (1,992)	$ 11	$ (83,626)	$ (95,844)	$ (569)	$ 12,787	$ (100,548)	$ (1,022)	$ 4,704	$ 455	$ (2)