Segment Information - Summary of Financial Information by Reportable Segment (Detail) - Successor [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Revenues:
Total revenues before expenses and reorganization items	$ 16,902	$ 155,491
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	12,854	216,580
Total assets	23,718,591	25,386,610	$ 23,728,070
Net investment income	60,821	72,983
Amortization of insurance intangible assets	50,890	37,432
Interest expense	30,430	27,908
Unaffiliated Customers [Member]
Revenues:
Total revenues before expenses and reorganization items	15,770	154,463
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	11,722	215,552
Equity Method Investee [Member]
Revenues:
Total revenues before expenses and reorganization items	1,132	1,028
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	1,132	1,028
Financial Guarantee [Member]
Revenues:
Total revenues before expenses and reorganization items	96,602
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	96,794	255,466
Financial Services [Member]
Revenues:
Total revenues before expenses and reorganization items	(83,552)
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	(84,301)	(38,892)
Corporate, Non-Segment [Member]
Revenues:
Total revenues before expenses and reorganization items	3,890	1,358
Inter-segment Eliminations [Member]
Revenues:
Total revenues before expenses and reorganization items	(38)	0
Operating Segments [Member] | Financial Guarantee [Member]
Revenues:
Total revenues before expenses and reorganization items		192,071
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations		(539)
Total assets	23,045,239	24,676,608
Net investment income	57,713	71,470
Amortization of insurance intangible assets	50,890	37,432
Interest expense	30,284	27,585
Operating Segments [Member] | Financial Guarantee [Member] | Unaffiliated Customers [Member]
Revenues:
Total revenues before expenses and reorganization items	97,374	191,814
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	98,417	256,005
Operating Segments [Member] | Financial Guarantee [Member] | Equity Method Investee [Member]
Revenues:
Total revenues before expenses and reorganization items	0	0
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	0	0
Operating Segments [Member] | Financial Guarantee [Member] | Inter-segment Eliminations [Member]
Revenues:
Total revenues before expenses and reorganization items	(772)	257
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	(1,623)
Operating Segments [Member] | Financial Services [Member]
Revenues:
Total revenues before expenses and reorganization items		(37,938)
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations		(312)
Total assets	390,661	408,090
Net investment income	203	128
Amortization of insurance intangible assets	0	0
Interest expense	146	323
Operating Segments [Member] | Financial Services [Member] | Unaffiliated Customers [Member]
Revenues:
Total revenues before expenses and reorganization items	(83,214)	(37,708)
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	(83,847)	(38,580)
Operating Segments [Member] | Financial Services [Member] | Equity Method Investee [Member]
Revenues:
Total revenues before expenses and reorganization items	0	0
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	0	0
Operating Segments [Member] | Financial Services [Member] | Inter-segment Eliminations [Member]
Revenues:
Total revenues before expenses and reorganization items	(338)	(230)
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	(454)
Inter-segment Eliminations [Member]
Revenues:
Total revenues before expenses and reorganization items	(38)	0
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	0	0
Total assets	5,806	18,474
Net investment income	0	0
Amortization of insurance intangible assets	0	0
Interest expense	0	0
Inter-segment Eliminations [Member] | Unaffiliated Customers [Member]
Revenues:
Total revenues before expenses and reorganization items	0	0
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	0	0
Inter-segment Eliminations [Member] | Equity Method Investee [Member]
Revenues:
Total revenues before expenses and reorganization items	0	0
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	0	0
Inter-segment Eliminations [Member] | Corporate, Non-Segment [Member]
Revenues:
Total revenues before expenses and reorganization items	1,148	(27)
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	2,077	851
Corporate, Non-Segment [Member]
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	361	6
Total assets	276,885	283,438
Net investment income	2,905	1,385
Amortization of insurance intangible assets	0	0
Corporate, Non-Segment [Member] | Unaffiliated Customers [Member]
Revenues:
Total revenues before expenses and reorganization items	1,610	357
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	(2,848)	(1,873)
Corporate, Non-Segment [Member] | Equity Method Investee [Member]
Revenues:
Total revenues before expenses and reorganization items	1,132	1,028
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	1,132	1,028
Corporate, Non-Segment [Member] | Corporate, Non-Segment [Member]
Pre-tax income (loss) from continuing operations:
Interest expense	$ 0	$ 0