Investments - Summary of Fair Value, Including Financial Guarantee, and Weighted-Average Underlying Rating, Excluding Financial Guarantee, of Insured Securities (Detail) - Successor [Member] - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Standard & Poor's, CC Rating [Member] | Ambac Assurance Corporation [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors	$ 2,277,153
Standard & Poor's, A- Rating [Member] | National Public Finance Guarantee Corporation [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors	47,846	$ 67,895
Standard & Poor's, CCC+ Rating [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors	2,408,359
Standard & Poor's, CCC+ Rating [Member] | Ambac Assurance Corporation [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors		2,199,719
Standard & Poor's, A Rating [Member] | Assured Guaranty Municipal Corporation [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors		119,492
Standard & Poor's, A+ Rating [Member] | Assured Guaranty Municipal Corporation [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors	57,715
Standard & Poor's, A+ Rating [Member] | MBIA Insurance Corporation [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors	25,645	32,460
Standard & Poor's, CCC Rating [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors		2,419,566
Municipal Bonds [Member] | Standard & Poor's, CC Rating [Member] | Ambac Assurance Corporation [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors	60,836
Municipal Bonds [Member] | Standard & Poor's, A- Rating [Member] | National Public Finance Guarantee Corporation [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors	47,846	67,895
Municipal Bonds [Member] | Standard & Poor's, CCC+ Rating [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors	166,397
Municipal Bonds [Member] | Standard & Poor's, CCC+ Rating [Member] | Ambac Assurance Corporation [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors		53,164
Municipal Bonds [Member] | Standard & Poor's, A Rating [Member] | Assured Guaranty Municipal Corporation [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors		119,492
Municipal Bonds [Member] | Standard & Poor's, A+ Rating [Member] | Assured Guaranty Municipal Corporation [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors	57,715
Municipal Bonds [Member] | Standard & Poor's, CCC Rating [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors		240,551
Corporate Debt Securities [Member] | Standard & Poor's, A- Rating [Member] | National Public Finance Guarantee Corporation [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors	0	0
Corporate Debt Securities [Member] | Standard & Poor's, CCC+ Rating [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors	25,645
Corporate Debt Securities [Member] | Standard & Poor's, A Rating [Member] | Assured Guaranty Municipal Corporation [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors		0
Corporate Debt Securities [Member] | Standard & Poor's, A+ Rating [Member] | Assured Guaranty Municipal Corporation [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors	0
Corporate Debt Securities [Member] | Standard & Poor's, A+ Rating [Member] | MBIA Insurance Corporation [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors	25,645	32,460
Corporate Debt Securities [Member] | Standard & Poor's, CCC Rating [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors		32,460
Mortgage and Asset-Backed Securities [Member] | Standard & Poor's, CC Rating [Member] | Ambac Assurance Corporation [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors	2,216,317
Mortgage and Asset-Backed Securities [Member] | Standard & Poor's, CCC+ Rating [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors	2,216,317
Mortgage and Asset-Backed Securities [Member] | Standard & Poor's, CCC+ Rating [Member] | Ambac Assurance Corporation [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors		2,146,555
Mortgage and Asset-Backed Securities [Member] | Standard & Poor's, CCC Rating [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors		2,146,555
Short-Term [Member] | Standard & Poor's, CCC+ Rating [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors	$ 0
Short-Term [Member] | Standard & Poor's, CCC Rating [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors		$ 0