Net Income Per Share - Reconciliation of Common Shares Used for Basic and Diluted Earnings Per Share (Detail)	3 Months Ended
	Mar. 31, 2014 Successor Ambac [Member]	Mar. 31, 2014 Successor Ambac [Member] Employee Stock Option [Member]	Mar. 31, 2014 Successor Ambac [Member] Restricted Stock Units [Member]	Mar. 31, 2014 Successor Ambac [Member] Warrants [Member]	Mar. 31, 2014 Successor Ambac [Member] Employee Stock Option [Member]	Mar. 31, 2013 Predecessor Ambac [Member]	Mar. 31, 2013 Predecessor Ambac [Member] Employee Stock Option [Member]	Mar. 31, 2013 Predecessor Ambac [Member] Restricted Stock Units [Member]	Mar. 31, 2013 Predecessor Ambac [Member] Warrants [Member]	Mar. 31, 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	45,042,823					302,469,516
Effect of potential dilutive shares:
Effect of potential dilutive shares				1,998,028	4,891			109,738
Weighted average number of common shares and potential dilutive shares used for diluted earnings per share	47,045,742					302,579,254
Anti-dilutive shares excluded from reconciliation			1,599				480,350