Schedule II - Reorganization Items Schedule II - Reorganization Items (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Apr. 30, 2013
Reorganization Items [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired				50.00%
Successor [Member]
Reorganization Items [Line Items]
Total reorganization items	$ 0	$ 0	$ 211
Ambac Financial Group, Inc Parent Company Only [Member] | Successor [Member]
Reorganization Items [Line Items]
Total reorganization items	$ 0	$ 0	$ 211