Segment Information - Schedule of Gross Premiums Written, Net Premiums Earned and Net Change in Fair Value of Credit Derivatives (Detail) - USD ($) $ in Thousands	3 Months Ended								4 Months Ended	8 Months Ended	12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Apr. 30, 2013	Dec. 31, 2013	Dec. 31, 2015	Dec. 31, 2014
Successor [Member]
Segment Reporting Information [Line Items]
Gross Premiums Written	$ (18,732)	$ (8,710)	$ (11,192)	$ 1,062	$ (223,358)	$ (13,700)	$ (45,486)	$ (5,766)		$ (80,309)	$ (37,572)	$ (288,310)
Net premiums earned	114,463	71,535	60,879	65,718	33,969	64,831	65,013	82,547		213,518	312,595	246,360
Net Change In Fair Value Of Credit Derivatives	$ (3,045)	$ 36,952	$ 10,293	$ (2,499)	$ 10,327	$ 7,416	$ (1,219)	$ 7,382		192,869	41,701	23,906
Successor [Member] | Reportable Geographical Components [Member] | United States [Member]
Segment Reporting Information [Line Items]
Gross Premiums Written										(61,255)	(13,028)	(46,279)
Net premiums earned										165,099	229,658	197,154
Net Change In Fair Value Of Credit Derivatives										122,696	39,633	8,669
Successor [Member] | Reportable Geographical Components [Member] | United Kingdom [Member]
Segment Reporting Information [Line Items]
Gross Premiums Written										(7,368)	3,652	(221,516)
Net premiums earned										35,387	68,799	31,672
Net Change In Fair Value Of Credit Derivatives										22,548	0	0
Successor [Member] | Reportable Geographical Components [Member] | Other International [Member]
Segment Reporting Information [Line Items]
Gross Premiums Written										(11,686)	(28,196)	(20,515)
Net premiums earned										13,032	14,138	17,534
Net Change In Fair Value Of Credit Derivatives										$ 47,625	$ 2,068	$ 15,237
Predecessor [Member]
Segment Reporting Information [Line Items]
Gross Premiums Written									$ (14,125)
Net premiums earned									130,000
Net Change In Fair Value Of Credit Derivatives									(60,384)
Predecessor [Member] | Reportable Geographical Components [Member] | United States [Member]
Segment Reporting Information [Line Items]
Gross Premiums Written									(16,102)
Net premiums earned									104,594
Net Change In Fair Value Of Credit Derivatives									(31,134)
Predecessor [Member] | Reportable Geographical Components [Member] | United Kingdom [Member]
Segment Reporting Information [Line Items]
Gross Premiums Written									10,673
Net premiums earned									18,071
Net Change In Fair Value Of Credit Derivatives									(5,861)
Predecessor [Member] | Reportable Geographical Components [Member] | Other International [Member]
Segment Reporting Information [Line Items]
Gross Premiums Written									(8,696)
Net premiums earned									7,335
Net Change In Fair Value Of Credit Derivatives									$ (23,389)