Financial Guarantee Insurance Contracts - Summary of Rollforward of RMBS Subrogation, by Estimation Approach (Detail) - Successor [Member] - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Subrogation By Estimation Approach [Roll Forward]
Discounted RMBS subrogation (gross of reinsurance), beginning balance	$ 2,829,575
Changes recognized
Discounted RMBS subrogation (gross of reinsurance), ending balance	1,883,826
Random Samples [Member]
Subrogation By Estimation Approach [Roll Forward]
Discounted RMBS subrogation (gross of reinsurance), beginning balance	2,829,575	$ 2,523,540
Changes recognized
Impact of sponsor actions	(995,000)	0
Other Changes Rmbs Subrogation	49,251	33,034
Discounted RMBS subrogation (gross of reinsurance), ending balance	$ 1,883,826	$ 2,556,574