Net Income Per Share - Reconciliation of Common Shares Used for Basic and Diluted Earnings Per Share (Detail)	2 Months Ended	3 Months Ended	6 Months Ended	2 Months Ended	3 Months Ended	6 Months Ended	2 Months Ended	3 Months Ended	6 Months Ended	2 Months Ended	3 Months Ended	6 Months Ended	2 Months Ended	3 Months Ended	6 Months Ended	2 Months Ended	3 Months Ended	6 Months Ended	1 Months Ended	4 Months Ended	1 Months Ended	4 Months Ended	1 Months Ended	4 Months Ended	1 Months Ended	4 Months Ended	1 Months Ended	4 Months Ended	1 Months Ended	4 Months Ended
	Jun. 30, 2013 Successor Ambac [Member]	Jun. 30, 2014 Successor Ambac [Member]	Jun. 30, 2014 Successor Ambac [Member]	Jun. 30, 2013 Successor Ambac [Member] Employee Stock Option [Member]	Jun. 30, 2014 Successor Ambac [Member] Employee Stock Option [Member]	Jun. 30, 2014 Successor Ambac [Member] Employee Stock Option [Member]	Jun. 30, 2013 Successor Ambac [Member] Restricted Stock Units [Member]	Jun. 30, 2014 Successor Ambac [Member] Restricted Stock Units [Member]	Jun. 30, 2014 Successor Ambac [Member] Restricted Stock Units [Member]	Jun. 30, 2013 Successor Ambac [Member] Performance Shares [Member]	Jun. 30, 2014 Successor Ambac [Member] Performance Shares [Member]	Jun. 30, 2014 Successor Ambac [Member] Performance Shares [Member]	Jun. 30, 2013 Successor Ambac [Member] Warrants [Member]	Jun. 30, 2014 Successor Ambac [Member] Warrants [Member]	Jun. 30, 2014 Successor Ambac [Member] Warrants [Member]	Jun. 30, 2013 Successor Ambac [Member] Employee Stock Option [Member]	Jun. 30, 2014 Successor Ambac [Member] Employee Stock Option [Member]	Jun. 30, 2014 Successor Ambac [Member] Employee Stock Option [Member]	Apr. 30, 2013 Predecessor Ambac [Member]	Apr. 30, 2013 Predecessor Ambac [Member]	Apr. 30, 2013 Predecessor Ambac [Member] Employee Stock Option [Member]	Apr. 30, 2013 Predecessor Ambac [Member] Employee Stock Option [Member]	Apr. 30, 2013 Predecessor Ambac [Member] Restricted Stock Units [Member]	Apr. 30, 2013 Predecessor Ambac [Member] Restricted Stock Units [Member]	Apr. 30, 2013 Predecessor Ambac [Member] Performance Shares [Member]	Apr. 30, 2013 Predecessor Ambac [Member] Performance Shares [Member]	Apr. 30, 2013 Predecessor Ambac [Member] Warrants [Member]	Apr. 30, 2013 Predecessor Ambac [Member] Warrants [Member]	Apr. 30, 2013 Predecessor Ambac [Member] Employee Stock Option [Member]	Apr. 30, 2013 Predecessor Ambac [Member] Employee Stock Option [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average number of common shares used for basic earnings per share	45,000,653	45,091,983	45,067,539																302,469,626	302,469,544
Effect of potential dilutive shares:
Effect of potential dilutive shares							0	0	0	0	0	0	1,575,064	0	0	0	0	0					109,593	109,701	0	0	0	0	0	0
Weighted average number of common shares and potential dilutive shares used for diluted earnings per share	46,575,717	45,091,983	45,067,539																302,579,219	302,579,245
Anti-dilutive shares excluded from reconciliation					66,668	66,668		74,341	94,131					5,040,775	5,040,784						461,150	475,550	0		0		0