Schedule II - Reorganization Items Schedule II - Reorganization Items (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
Reorganization Items [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired									50.00%
Successor [Member]
Reorganization Items [Line Items]
Professional fees										$ 460	$ 0	$ 204
Gain from cancellation and satisfaction of Predecessor Ambac debt										0	0	0
Fresh start reporting adjustments										0	0	0
Total reorganization items	$ 0	$ 0	$ 0	$ 0	$ 0	$ 2	$ 186	$ 23		493	0	211
Predecessor [Member]
Reorganization Items [Line Items]
Professional fees									$ 4,483
Gain from cancellation and satisfaction of Predecessor Ambac debt									(1,521,435)
Fresh start reporting adjustments									(1,228,251)
Total reorganization items									(2,745,180)
Ambac Financial Group, Inc Parent Company Only [Member] | Successor [Member]
Reorganization Items [Line Items]
Total reorganization items										$ 493	$ 0	$ 211
Ambac Financial Group, Inc Parent Company Only [Member] | Predecessor [Member]
Reorganization Items [Line Items]
Total reorganization items									$ (2,745,180)