Segment Information - Summary of Financial Information by Reportable Segment (Detail) - Successor [Member] - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues:
Total revenues before expenses and reorganization items									$ 506,149	$ 644,658	$ 328,670
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations	$ (86,059)	$ 116,720	$ 61,511	$ 12,854	$ 395,576	$ (388,193)	$ 286,095	$ 216,580	105,026	510,058	493,253
Total assets	22,635,702				23,728,070				22,635,702	23,728,070	25,159,864
Net investment income	90,871	90,917	70,758	60,821	64,358	64,195	64,753	72,983	313,367	266,289	300,946
Amortization of insurance intangible assets	40,152	44,553	39,013	50,890	54,357	39,680	38,088	37,432	174,608	169,557	151,830
Interest expense	31,712	31,493	30,709	30,430	30,557	29,899	28,173	27,908	124,344	116,537	127,476
Goodwill, Impairment Loss	0	$ 0	$ 0	$ 0	0	$ (514,511)	$ 0	$ 0	0	514,511	0
Reorganization items									0	0	211
Unaffiliated Customers [Member]
Revenues:
Total revenues before expenses and reorganization items									501,485	640,322	327,275
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations									100,362	505,722	491,858
Equity Method Investee [Member]
Revenues:
Total revenues before expenses and reorganization items									4,664	4,336	1,395
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations									4,664	4,336	1,395
Intersegment [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
Financial Guarantee [Member]
Revenues:
Total revenues before expenses and reorganization items									524,403	680,011	507,802
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations									136,872	557,588	659,307
Total assets	21,987,068				23,108,387				21,987,068	23,108,387	24,448,346
Net investment income									300,102	256,636	298,020
Amortization of insurance intangible assets									174,608	169,557	151,830
Interest expense									123,720	115,630	125,892
Reorganization items											0
Financial Guarantee [Member] | Unaffiliated Customers [Member]
Revenues:
Total revenues before expenses and reorganization items									543,955	679,662	506,559
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations									159,978	560,332	684,750
Financial Guarantee [Member] | Equity Method Investee [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
Financial Guarantee [Member] | Intersegment [Member]
Revenues:
Total revenues before expenses and reorganization items									(19,552)	349	1,243
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations									(23,106)	(2,744)	(25,443)
Financial Services [Member]
Revenues:
Total revenues before expenses and reorganization items									(29,640)	(44,852)	(180,888)
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations									(32,723)	(48,252)	(184,486)
Total assets	313,710				348,130				313,710	348,130	412,510
Net investment income									778	548	1,123
Amortization of insurance intangible assets									0	0	0
Interest expense									624	907	1,584
Reorganization items											0
Financial Services [Member] | Unaffiliated Customers [Member]
Revenues:
Total revenues before expenses and reorganization items									(49,434)	(44,003)	(179,691)
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations									(52,013)	(46,869)	(182,941)
Financial Services [Member] | Equity Method Investee [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
Financial Services [Member] | Intersegment [Member]
Revenues:
Total revenues before expenses and reorganization items									19,794	(849)	(1,197)
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations									19,290	(1,383)	(1,545)
Corporate and Other [Member]
Revenues:
Total revenues before expenses and reorganization items									12,501	9,644	25,101
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations									877	722	18,432
Total assets	353,482				268,388				353,482	268,388	284,278
Net investment income									12,487	9,105	1,803
Amortization of insurance intangible assets									0	0	0
Interest expense									0	0	0
Reorganization items											211
Corporate and Other [Member] | Unaffiliated Customers [Member]
Revenues:
Total revenues before expenses and reorganization items									6,964	4,663	407
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations									(7,603)	(7,741)	(9,951)
Corporate and Other [Member] | Equity Method Investee [Member]
Revenues:
Total revenues before expenses and reorganization items									4,664	4,336	1,395
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations									4,664	4,336	1,395
Corporate and Other [Member] | Intersegment [Member]
Revenues:
Total revenues before expenses and reorganization items									873	645	23,299
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations									3,816	4,127	26,988
Operating Segments [Member] | Financial Guarantee [Member]
Pre-tax income (loss) from continuing operations:
Goodwill, Impairment Loss										514,511
Operating Segments [Member] | Financial Services [Member]
Pre-tax income (loss) from continuing operations:
Goodwill, Impairment Loss										0
Inter-segment Eliminations [Member]
Revenues:
Total revenues before expenses and reorganization items											(23,345)
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations											0
Total assets											14,730
Net investment income											0
Interest expense											0
Goodwill, Impairment Loss										0
Reorganization items											0
Inter-segment Eliminations [Member] | Unaffiliated Customers [Member]
Revenues:
Total revenues before expenses and reorganization items											0
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations											0
Inter-segment Eliminations [Member] | Intersegment [Member]
Revenues:
Total revenues before expenses and reorganization items									(1,115)	(145)	(23,345)
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations											0
Inter-segment Eliminations [Member] | Inter-segment Eliminations [Member]
Revenues:
Total revenues before expenses and reorganization items									(1,115)	(145)
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations									0	0
Total assets	$ (18,558)				$ 3,165				(18,558)	3,165
Net investment income									0	0
Amortization of insurance intangible assets									0	0	0
Interest expense									0	0
Inter-segment Eliminations [Member] | 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] | Inter-segment Eliminations [Member] | Equity Method Investee [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
Inter-segment Eliminations [Member] | Inter-segment Eliminations [Member] | Intersegment [Member]
Pre-tax income (loss) from continuing operations:
Pre-tax (loss) income from continuing operations									$ 0	0
Corporate, Non-Segment [Member] | Corporate, Non-Segment [Member]
Pre-tax income (loss) from continuing operations:
Goodwill, Impairment Loss										$ 0