Financial Guarantee Insurance Contracts - Summary of Balance of RMBS Subrogation Recoveries and Related Claim Liabilities, by Estimation Approach (Detail) (Successor Ambac [Member], USD $) In Thousands, unless otherwise specified	Mar. 31, 2014 Transactions	Dec. 31, 2013 Transactions
Schedule Of Balance Of Rmbs Subrogation Recoveries And Related Claim Liabilities By Estimation Approach [Line Items]
Count	48	48
Gross loss reserve before subrogation recoveries	$ 3,086,342	$ 3,163,772
Subrogation recoveries	(2,224,295)	(2,206,598)
Gross loss reserve after subrogation recoveries	862,047	957,174
Adverse Samples [Member]
Schedule Of Balance Of Rmbs Subrogation Recoveries And Related Claim Liabilities By Estimation Approach [Line Items]
Count	27	27
Gross loss reserve before subrogation recoveries	2,009,647	2,084,911
Subrogation recoveries	(1,218,681)	(1,252,773)
Gross loss reserve after subrogation recoveries	790,966	832,138
Random Samples [Member]
Schedule Of Balance Of Rmbs Subrogation Recoveries And Related Claim Liabilities By Estimation Approach [Line Items]
Count	21	21
Gross loss reserve before subrogation recoveries	1,076,695	1,078,861
Subrogation recoveries	(1,005,614)	(953,825)
Gross loss reserve after subrogation recoveries	$ 71,081	$ 125,036