Segment Information - Summary of Financial Information by Reportable Segment (Detail) (USD $) In Thousands, unless otherwise specified			3 Months Ended		5 Months Ended	9 Months Ended	3 Months Ended		5 Months Ended	9 Months Ended	3 Months Ended		5 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended	4 Months Ended			3 Months Ended		5 Months Ended	9 Months Ended	3 Months Ended		5 Months Ended	9 Months Ended	3 Months Ended		5 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended	3 Months Ended		5 Months Ended	9 Months Ended	3 Months Ended		5 Months Ended	9 Months Ended	3 Months Ended		5 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended	3 Months Ended		5 Months Ended	9 Months Ended	3 Months Ended		5 Months Ended	9 Months Ended	3 Months Ended		5 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended	3 Months Ended		5 Months Ended	9 Months Ended	3 Months Ended		5 Months Ended	9 Months Ended	3 Months Ended		5 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended	4 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014 Successor [Member]	Sep. 30, 2013 Successor [Member]	Sep. 30, 2013 Successor [Member]	Sep. 30, 2014 Successor [Member]	Sep. 30, 2014 Successor [Member] Unaffiliated Customers [Member]	Sep. 30, 2013 Successor [Member] Unaffiliated Customers [Member]	Sep. 30, 2013 Successor [Member] Unaffiliated Customers [Member]	Sep. 30, 2014 Successor [Member] Unaffiliated Customers [Member]	Sep. 30, 2014 Successor [Member] Intersegment [Member]	Sep. 30, 2013 Successor [Member] Intersegment [Member]	Sep. 30, 2013 Successor [Member] Intersegment [Member]	Sep. 30, 2014 Successor [Member] Intersegment [Member]	Sep. 30, 2014 Successor [Member] Equity Method Investee [Member]	Sep. 30, 2014 Successor [Member] Equity Method Investee [Member]	Apr. 30, 2013 Predecessor [Member]	Apr. 30, 2013 Predecessor [Member] Unaffiliated Customers [Member]	Apr. 30, 2013 Predecessor [Member] Intersegment [Member]	Sep. 30, 2014 Operating Segments [Member] Successor [Member] Inter-segment Eliminations [Member]	Sep. 30, 2013 Operating Segments [Member] Successor [Member] Inter-segment Eliminations [Member]	Sep. 30, 2013 Operating Segments [Member] Successor [Member] Inter-segment Eliminations [Member]	Sep. 30, 2014 Operating Segments [Member] Successor [Member] Inter-segment Eliminations [Member]	Sep. 30, 2014 Operating Segments [Member] Successor [Member] Inter-segment Eliminations [Member] Unaffiliated Customers [Member]	Sep. 30, 2013 Operating Segments [Member] Successor [Member] Inter-segment Eliminations [Member] Unaffiliated Customers [Member]	Sep. 30, 2013 Operating Segments [Member] Successor [Member] Inter-segment Eliminations [Member] Unaffiliated Customers [Member]	Sep. 30, 2014 Operating Segments [Member] Successor [Member] Inter-segment Eliminations [Member] Unaffiliated Customers [Member]	Sep. 30, 2014 Operating Segments [Member] Successor [Member] Inter-segment Eliminations [Member] Intersegment [Member]	Sep. 30, 2013 Operating Segments [Member] Successor [Member] Inter-segment Eliminations [Member] Intersegment [Member]	Sep. 30, 2013 Operating Segments [Member] Successor [Member] Inter-segment Eliminations [Member] Intersegment [Member]	Sep. 30, 2014 Operating Segments [Member] Successor [Member] Inter-segment Eliminations [Member] Intersegment [Member]	Sep. 30, 2014 Operating Segments [Member] Successor [Member] Inter-segment Eliminations [Member] Equity Method Investee [Member]	Sep. 30, 2014 Operating Segments [Member] Successor [Member] Inter-segment Eliminations [Member] Equity Method Investee [Member]	Sep. 30, 2014 Operating Segments [Member] Successor [Member] Financial Guarantee [Member]	Sep. 30, 2013 Operating Segments [Member] Successor [Member] Financial Guarantee [Member]	Sep. 30, 2013 Operating Segments [Member] Successor [Member] Financial Guarantee [Member]	Sep. 30, 2014 Operating Segments [Member] Successor [Member] Financial Guarantee [Member]	Sep. 30, 2014 Operating Segments [Member] Successor [Member] Financial Guarantee [Member] Unaffiliated Customers [Member]	Sep. 30, 2013 Operating Segments [Member] Successor [Member] Financial Guarantee [Member] Unaffiliated Customers [Member]	Sep. 30, 2013 Operating Segments [Member] Successor [Member] Financial Guarantee [Member] Unaffiliated Customers [Member]	Sep. 30, 2014 Operating Segments [Member] Successor [Member] Financial Guarantee [Member] Unaffiliated Customers [Member]	Sep. 30, 2014 Operating Segments [Member] Successor [Member] Financial Guarantee [Member] Intersegment [Member]	Sep. 30, 2013 Operating Segments [Member] Successor [Member] Financial Guarantee [Member] Intersegment [Member]	Sep. 30, 2013 Operating Segments [Member] Successor [Member] Financial Guarantee [Member] Intersegment [Member]	Sep. 30, 2014 Operating Segments [Member] Successor [Member] Financial Guarantee [Member] Intersegment [Member]	Sep. 30, 2014 Operating Segments [Member] Successor [Member] Financial Guarantee [Member] Equity Method Investee [Member]	Sep. 30, 2014 Operating Segments [Member] Successor [Member] Financial Guarantee [Member] Equity Method Investee [Member]	Sep. 30, 2014 Operating Segments [Member] Successor [Member] Financial Services [Member]	Sep. 30, 2013 Operating Segments [Member] Successor [Member] Financial Services [Member]	Sep. 30, 2013 Operating Segments [Member] Successor [Member] Financial Services [Member]	Sep. 30, 2014 Operating Segments [Member] Successor [Member] Financial Services [Member]	Sep. 30, 2014 Operating Segments [Member] Successor [Member] Financial Services [Member] Unaffiliated Customers [Member]	Sep. 30, 2013 Operating Segments [Member] Successor [Member] Financial Services [Member] Unaffiliated Customers [Member]	Sep. 30, 2013 Operating Segments [Member] Successor [Member] Financial Services [Member] Unaffiliated Customers [Member]	Sep. 30, 2014 Operating Segments [Member] Successor [Member] Financial Services [Member] Unaffiliated Customers [Member]	Sep. 30, 2014 Operating Segments [Member] Successor [Member] Financial Services [Member] Intersegment [Member]	Sep. 30, 2013 Operating Segments [Member] Successor [Member] Financial Services [Member] Intersegment [Member]	Sep. 30, 2013 Operating Segments [Member] Successor [Member] Financial Services [Member] Intersegment [Member]	Sep. 30, 2014 Operating Segments [Member] Successor [Member] Financial Services [Member] Intersegment [Member]	Sep. 30, 2014 Operating Segments [Member] Successor [Member] Financial Services [Member] Equity Method Investee [Member]	Sep. 30, 2014 Operating Segments [Member] Successor [Member] Financial Services [Member] Equity Method Investee [Member]	Sep. 30, 2014 Operating Segments [Member] Successor [Member] Corporate and Other [Member]	Sep. 30, 2013 Operating Segments [Member] Successor [Member] Corporate and Other [Member]	Sep. 30, 2013 Operating Segments [Member] Successor [Member] Corporate and Other [Member]	Sep. 30, 2014 Operating Segments [Member] Successor [Member] Corporate and Other [Member]	Sep. 30, 2014 Operating Segments [Member] Successor [Member] Corporate and Other [Member] Unaffiliated Customers [Member]	Sep. 30, 2013 Operating Segments [Member] Successor [Member] Corporate and Other [Member] Unaffiliated Customers [Member]	Sep. 30, 2013 Operating Segments [Member] Successor [Member] Corporate and Other [Member] Unaffiliated Customers [Member]	Sep. 30, 2014 Operating Segments [Member] Successor [Member] Corporate and Other [Member] Unaffiliated Customers [Member]	Sep. 30, 2014 Operating Segments [Member] Successor [Member] Corporate and Other [Member] Intersegment [Member]	Sep. 30, 2013 Operating Segments [Member] Successor [Member] Corporate and Other [Member] Intersegment [Member]	Sep. 30, 2013 Operating Segments [Member] Successor [Member] Corporate and Other [Member] Intersegment [Member]	Sep. 30, 2014 Operating Segments [Member] Successor [Member] Corporate and Other [Member] Intersegment [Member]	Sep. 30, 2014 Operating Segments [Member] Successor [Member] Corporate and Other [Member] Equity Method Investee [Member]	Sep. 30, 2014 Operating Segments [Member] Successor [Member] Corporate and Other [Member] Equity Method Investee [Member]	Apr. 30, 2013 Operating Segments [Member] Predecessor [Member] Inter-segment Eliminations [Member]	Apr. 30, 2013 Operating Segments [Member] Predecessor [Member] Inter-segment Eliminations [Member] Unaffiliated Customers [Member]	Apr. 30, 2013 Operating Segments [Member] Predecessor [Member] Inter-segment Eliminations [Member] Intersegment [Member]	Apr. 30, 2013 Operating Segments [Member] Predecessor [Member] Financial Guarantee [Member]	Apr. 30, 2013 Operating Segments [Member] Predecessor [Member] Financial Guarantee [Member] Unaffiliated Customers [Member]	Apr. 30, 2013 Operating Segments [Member] Predecessor [Member] Financial Guarantee [Member] Intersegment [Member]	Apr. 30, 2013 Operating Segments [Member] Predecessor [Member] Financial Services [Member]	Apr. 30, 2013 Operating Segments [Member] Predecessor [Member] Financial Services [Member] Unaffiliated Customers [Member]	Apr. 30, 2013 Operating Segments [Member] Predecessor [Member] Financial Services [Member] Intersegment [Member]	Apr. 30, 2013 Operating Segments [Member] Predecessor [Member] Corporate and Other [Member]	Apr. 30, 2013 Operating Segments [Member] Predecessor [Member] Corporate and Other [Member] Unaffiliated Customers [Member]	Apr. 30, 2013 Operating Segments [Member] Predecessor [Member] Corporate and Other [Member] Intersegment [Member]	Sep. 30, 2013 Corporate and Other [Member] Successor [Member]	Apr. 30, 2013 Corporate and Other [Member] Predecessor [Member]
Revenues:
Total revenues before expenses and reorganization items			$ 155,339	$ 171,652	$ 414,067	$ 321,810	$ 154,968	$ 171,652	$ 414,067	$ 321,439	$ 0	$ 0	$ 0	$ 0	$ 371	$ 371	$ 640,388	$ 640,388	$ 0	$ (5,856)	$ (8,299)	$ (13,749)	$ (23,345)	$ 0	$ 0	$ 0	$ 0	$ (5,856)	$ (8,299)	$ (13,749)	$ (23,345)	$ 0	$ 0	$ 170,572	$ 157,894	$ 318,198	$ 438,528	$ 170,335	$ 157,382	$ 317,287	$ 437,591	$ 237	$ 512	$ 911	$ 937	$ 0	$ 0	$ (15,664)	$ 13,672	$ 95,788	$ (117,195)	$ (15,445)	$ 14,144	$ 96,634	$ (116,294)	$ (219)	$ (472)	$ (846)	$ (901)	$ 0	$ 0	$ 6,287	$ 8,385	$ 13,830	$ 23,822	$ 78	$ 126	$ 146	$ 142	$ 5,838	$ 8,259	$ 13,684	$ 23,309	$ 371	$ 371	$ (197,113)	$ 0	$ (197,113)	$ 633,950	$ 633,010	$ 940	$ 6,457	$ 7,339	$ (882)	$ 197,094	$ 39	$ 197,055
Pre-tax income (loss) from continuing operations:
Pre-tax income (loss) from continuing operations			84,773	231,601	437,396	33,659	84,402	231,601	437,396	33,288	0	0	0	0	371	371	3,348,033	3,348,033	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	95,534	210,342	329,735	132,556	101,975	219,006	343,896	157,551	(6,441)	(8,664)	(14,161)	(24,995)	0	0	(16,585)	12,189	93,358	(120,437)	(16,304)	12,812	94,504	(119,287)	(281)	(623)	(1,146)	(1,150)	0	0	5,824	9,070	14,303	21,540	(1,269)	(217)	(1,004)	(4,976)	6,722	9,287	15,307	26,145	371	371	0	0	0	1,632,978	1,830,165	(197,187)	2,132	3,233	(1,101)	1,712,923	1,514,635	198,288
Total assets	26,590,785	27,092,477	26,590,785	28,633,638	28,633,638	26,590,785											28,853,435			0	0	0	0											25,922,462	28,117,113	28,117,113	25,922,462											373,200	477,111	477,111	373,200											295,123	39,414	39,414	295,123														28,287,321			536,711						39,414	29,403
Total net investment income			83,581	52,126	78,322	234,475											116,740			0	0	0	0											82,978	51,637	77,652	232,995											154	474	632	967											449	15	38	513											0			115,129			1,572			39
Amortization of insurance intangible assets			41,908	37,473	62,425	109,878											0			0	0	0	0											41,908	37,473	62,425	109,878											0	0	0	0											0	0	0	0
Total expenses before reorganization items			31,841	31,817	52,961	96,122											31,025			0	0	0	0											31,491	31,281	52,057	94,886											350	536	904	1,236											0	0	0	0											0			29,718			1,307			0
Pre-tax (loss) income from continuing operations			$ 2	$ 4	$ 428	$ 211											$ (2,745,180)			$ 0	$ 0	$ 0	$ 0											$ 0	$ 0	$ 0	$ 0											$ 0	$ 0	$ 0	$ 0											$ 2	$ 4	$ 428	$ 211											$ 0			$ (1,231,550)			$ 1,505			$ (1,515,135)