Financial Guarantee Insurance Contracts - Summary of Balance of RMBS Subrogation Recoveries and Related Claim Liabilities, by Estimation Approach (Detail) - USD ($) $ in Thousands	4 Months Ended	8 Months Ended	12 Months Ended
	Apr. 30, 2013	Dec. 31, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2012
Successor [Member]
Schedule Of Balance Of Rmbs Subrogation Recoveries And Related Claim Liabilities By Estimation Approach [Line Items]
Subrogation recoveries	$ 2,482,918	$ 2,206,598	$ 2,829,575	$ 2,523,540
Additional Transactions Reviewed Changes in RMBS Subrogation		2,451	0	24,565
Changes in Estimation Approach In Rmbs Subrogation		0	0	198,875
Impact Of Sponsor Actions In Residential Mortgage Backed Securities Subrogation		98	0	(146,270)
Other Changes Rmbs Subrogation		(278,869)	306,035	239,772
Successor [Member] | Random Samples [Member]
Schedule Of Balance Of Rmbs Subrogation Recoveries And Related Claim Liabilities By Estimation Approach [Line Items]
Gross loss reserve before subrogation recoveries			1,850,804	1,897,426
Subrogation recoveries			2,829,575	2,523,540
Gross loss reserve after subrogation recoveries			(978,771)	(626,114)
Predecessor [Member]
Schedule Of Balance Of Rmbs Subrogation Recoveries And Related Claim Liabilities By Estimation Approach [Line Items]
Subrogation recoveries	2,482,918				$ 2,523,225
Additional Transactions Reviewed Changes in RMBS Subrogation	0
Changes in Estimation Approach In Rmbs Subrogation	0
Impact Of Sponsor Actions In Residential Mortgage Backed Securities Subrogation	(54,195)
Other Changes Rmbs Subrogation	13,888
Adverse Samples [Member] | Successor [Member]
Schedule Of Balance Of Rmbs Subrogation Recoveries And Related Claim Liabilities By Estimation Approach [Line Items]
Subrogation recoveries	1,478,666	1,252,773	0	0
Additional Transactions Reviewed Changes in RMBS Subrogation		0	0	0
Changes in Estimation Approach In Rmbs Subrogation		0	0	(1,218,681)
Impact Of Sponsor Actions In Residential Mortgage Backed Securities Subrogation		98	0	0
Other Changes Rmbs Subrogation		(225,991)	0	(34,092)
Adverse Samples [Member] | Predecessor [Member]
Schedule Of Balance Of Rmbs Subrogation Recoveries And Related Claim Liabilities By Estimation Approach [Line Items]
Subrogation recoveries	1,478,666				1,442,817
Additional Transactions Reviewed Changes in RMBS Subrogation	0
Changes in Estimation Approach In Rmbs Subrogation	0
Impact Of Sponsor Actions In Residential Mortgage Backed Securities Subrogation	0
Other Changes Rmbs Subrogation	35,849
Random Samples [Member] | Successor [Member]
Schedule Of Balance Of Rmbs Subrogation Recoveries And Related Claim Liabilities By Estimation Approach [Line Items]
Subrogation recoveries	1,004,252	953,825	2,829,575	2,523,540
Additional Transactions Reviewed Changes in RMBS Subrogation		2,451	0	24,565
Changes in Estimation Approach In Rmbs Subrogation		0	0	1,417,556
Impact Of Sponsor Actions In Residential Mortgage Backed Securities Subrogation		0	0	(146,270)
Other Changes Rmbs Subrogation		$ (52,878)	$ 306,035	$ 273,864
Random Samples [Member] | Predecessor [Member]
Schedule Of Balance Of Rmbs Subrogation Recoveries And Related Claim Liabilities By Estimation Approach [Line Items]
Subrogation recoveries	1,004,252				$ 1,080,408
Additional Transactions Reviewed Changes in RMBS Subrogation	0
Changes in Estimation Approach In Rmbs Subrogation	0
Impact Of Sponsor Actions In Residential Mortgage Backed Securities Subrogation	(54,195)
Other Changes Rmbs Subrogation	$ (21,961)