Segment Information - Summary of Financial Information by Reportable Segment (Detail) - Successor [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Revenues:
Total revenues before expenses and reorganization items	$ 106,732	$ 230,752	$ 123,634	$ 386,243
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	61,511	286,095	74,365	502,675
Total assets	23,199,111	25,513,636	23,199,111	25,513,636	$ 23,728,070
Net investment income	70,758	64,753	131,579	137,736
Amortization of insurance intangible assets	39,013	38,088	89,903	75,520
Interest expense	30,709	28,173	61,139	56,081
Unaffiliated Customers [Member]
Revenues:
Total revenues before expenses and reorganization items	105,582	229,697	121,353	384,160
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	60,361	285,040	72,084	500,592
Equity Method Investee [Member]
Revenues:
Total revenues before expenses and reorganization items	1,150	1,055	2,281	2,083
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	1,150	1,055	2,281	2,083
Inter-segment Eliminations [Member]
Revenues:
Total revenues before expenses and reorganization items				0
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations		163		163
Financial Guarantee [Member]
Revenues:
Total revenues before expenses and reorganization items	140,411	177,507	238,161	369,578
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	99,744	235,895	196,539	491,361
Financial Services [Member]
Revenues:
Total revenues before expenses and reorganization items	(36,507)	51,008	(120,059)	13,070
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	(37,283)	50,122	(121,584)	11,230
Corporate, Non-Segment [Member]
Revenues:
Total revenues before expenses and reorganization items	3,286	2,274	6,027	3,632
Inter-segment Eliminations [Member]
Revenues:
Total revenues before expenses and reorganization items	(458)	(37)	(495)	(37)
Operating Segments [Member] | Financial Guarantee [Member]
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations		(785)
Total assets	22,437,377	24,915,205	22,437,377	24,915,205
Net investment income	67,531	62,508	125,245	133,978
Amortization of insurance intangible assets	39,013	38,088	89,903	75,520
Interest expense	30,557	27,842	60,841	55,427
Operating Segments [Member] | Financial Guarantee [Member] | Unaffiliated Customers [Member]
Revenues:
Total revenues before expenses and reorganization items	139,947	177,502	237,322	369,316
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	99,327	236,680	197,745	492,685
Operating Segments [Member] | Financial Guarantee [Member] | Equity Method Investee [Member]
Revenues:
Total revenues before expenses and reorganization items	0	0	0	0
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	0	0	0	0
Operating Segments [Member] | Financial Guarantee [Member] | Inter-segment Eliminations [Member]
Revenues:
Total revenues before expenses and reorganization items	464	5	839	262
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	417		(1,206)	(1,324)
Operating Segments [Member] | Financial Services [Member]
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations		(252)
Total assets	407,942	316,954	407,942	316,954
Net investment income	198	134	401	262
Amortization of insurance intangible assets	0	0	0	0
Interest expense	152	331	298	654
Operating Segments [Member] | Financial Services [Member] | Unaffiliated Customers [Member]
Revenues:
Total revenues before expenses and reorganization items	(36,114)	51,139	(119,328)	13,431
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	(36,771)	50,374	(120,618)	11,794
Operating Segments [Member] | Financial Services [Member] | Equity Method Investee [Member]
Revenues:
Total revenues before expenses and reorganization items	0	0	0	0
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	0	0	0	0
Operating Segments [Member] | Financial Services [Member] | Inter-segment Eliminations [Member]
Revenues:
Total revenues before expenses and reorganization items	(393)	(131)	(731)	(361)
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	(512)		(966)	(564)
Inter-segment Eliminations [Member]
Revenues:
Total revenues before expenses and reorganization items	0	0	0
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	0	0	0	0
Total assets	4,242	5,379	4,242	5,379
Net investment income	0	0	0	0
Amortization of insurance intangible assets	0	0	0	0
Interest expense	0	0	0	0
Inter-segment Eliminations [Member] | Unaffiliated Customers [Member]
Revenues:
Total revenues before expenses and reorganization items	0	0	0	0
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	0	0	0	0
Inter-segment Eliminations [Member] | Equity Method Investee [Member]
Revenues:
Total revenues before expenses and reorganization items	0	0	0	0
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	0	0	0	0
Inter-segment Eliminations [Member] | Inter-segment Eliminations [Member]
Revenues:
Total revenues before expenses and reorganization items	(458)	(37)	(495)	(37)
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	0	163	0	163
Inter-segment Eliminations [Member] | Corporate, Non-Segment [Member]
Revenues:
Total revenues before expenses and reorganization items	387	163	387	136
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	95	874	2,172	1,725
Corporate, Non-Segment [Member]
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	(950)	(85)	(590)	(79)
Total assets	349,550	276,098	349,550	276,098
Net investment income	3,029	2,111	5,933	3,496
Amortization of insurance intangible assets	0	0	0	0
Corporate, Non-Segment [Member] | Unaffiliated Customers [Member]
Revenues:
Total revenues before expenses and reorganization items	1,749	1,056	3,359	1,413
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	(2,195)	(2,014)	(5,043)	(3,887)
Corporate, Non-Segment [Member] | Equity Method Investee [Member]
Revenues:
Total revenues before expenses and reorganization items	1,150	1,055	2,281	2,083
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	1,150	1,055	2,281	2,083
Corporate, Non-Segment [Member] | Corporate, Non-Segment [Member]
Pre-tax income (loss) from continuing operations:
Interest expense	$ 0	$ 0	$ 0	$ 0