Investments - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		3 Months Ended		3 Months Ended							3 Months Ended			5 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014 Successor Ambac [Member]	Dec. 31, 2013 Successor Ambac [Member]	Mar. 31, 2013 Predecessor Ambac [Member]	Mar. 31, 2014 Below Investment Grade Securities and Non-Rated Securities [Member]	Dec. 31, 2013 Below Investment Grade Securities and Non-Rated Securities [Member]	Mar. 31, 2014 Residential Mortgage-Backed Securities [Member]	Mar. 31, 2014 Ambac Wrapped Securities [Member]	Mar. 31, 2014 Asset-backed Securities [Member]	Mar. 31, 2014 Asset Backed, Military Housing, Fixed Rate Securities [Member] Security	Mar. 31, 2014 Gains (losses) on securities held as of reporting date [Member] Successor Ambac [Member]	Mar. 31, 2013 Gains (losses) on securities held as of reporting date [Member] Successor Ambac [Member]	Mar. 31, 2013 National Century Financial Enterprises, Inc. [Member]	Sep. 30, 2013 National Century Financial Enterprises, Inc. [Member]	Mar. 31, 2014 Fixed Income Securities [Member] Successor Ambac [Member]	Dec. 31, 2013 Fixed Income Securities [Member] Successor Ambac [Member]	Mar. 31, 2014 Fixed Income Securities [Member] Residential Mortgage-Backed Securities [Member] Successor Ambac [Member]	Dec. 31, 2013 Fixed Income Securities [Member] Residential Mortgage-Backed Securities [Member] Successor Ambac [Member]	Mar. 31, 2014 Fixed Income Securities [Member] Asset-backed Securities [Member] Successor Ambac [Member]	Dec. 31, 2013 Fixed Income Securities [Member] Asset-backed Securities [Member] Successor Ambac [Member]
Investment [Line Items]
Fair value of below investment grade securities and non-rated securities						$ 595,247	$ 826,969
Gross unrealized loss						33,433	36,946
Payment of permitted policy claim (percent)	25.00%
Future payment of permitted policy claim (percent)	45.00%
Unrealized losses on securities			83,446	116,634				20,408	16,258	24,618	24,333					83,446	116,634	20,408	18,105	24,618	36,598
Number of securities in unrealized loss position											5
Investment realized losses			16,289		46,060
Cash recoveries	7,760													39,978	1,441
Securities fair value	6,811	6,799
Fair value of securities held by bankruptcy remote trust	236,674	240,150
Other investments			$ 1,994		$ (543)							$ 2,449	$ 614