Basis of Presentation and Significant Accounting Policies (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended		2 Months Ended	3 Months Ended						8 Months Ended	1 Months Ended	3 Months Ended	4 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Jun. 30, 2013	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Dec. 31, 2013	Apr. 30, 2013	Mar. 31, 2013	Apr. 30, 2013	Dec. 31, 2012
Fresh-Start Adjustment [Line Items]
Deferred Amounts and Junior Deferred Amounts Accrued Interest Rate	5.10%
Business Acquisition, Percentage of Voting Interests Acquired											50.00%		50.00%
Goodwill [Roll Forward]
Ending balance											$ 514,511		$ 514,511
Currency Translation, Weighted Average Risk Free Discount Rate	2.70%	3.00%		2.70%				3.00%		3.00%
Financial Guarantee Insurance Contracts, Premium Received over Contract Period, Premium Receivable, Weighted Average Collection Period	10 years 1 month 6 days	9 years 7 months 6 days
Successor [Member]
Goodwill [Roll Forward]
Beginning balance	514,511		514,511				514,511			514,511
Goodwill recorded in connection with emergence from Chapter 11	0									514,511
Accumulated impairment loss	0									0
Ending balance	514,511	514,511		514,511				514,511		514,511
Financial Guarantee Insurance Contracts, Accelerated Premium Revenue, Amount	29,964									56,541
U.S. Trustee Fees	7									33
Professional fees	204									460
Gain From Cancellation and Satisfaction of Predecessor Ambac Debt	0									0
Fresh Start Adjustments	0									0
Reorganization items	211		424	0	2	186	23	65	4	493
Predecessor [Member]
Fresh-Start Adjustment [Line Items]
Deferred Policy Acquisition Cost, Amortization Expense													6,480	25,465
Goodwill [Roll Forward]
Beginning balance		0										0	0	0
Goodwill recorded in connection with emergence from Chapter 11													0	0
Accumulated impairment loss													0	0
Ending balance											0		0	0
Financial Guarantee Insurance Contracts, Accelerated Premium Revenue, Amount													36,433	127,628
U.S. Trustee Fees													23	50
Professional fees													4,483	7,165
Gain From Cancellation and Satisfaction of Predecessor Ambac Debt													(1,521,435)	0
Fresh Start Adjustments													(1,228,251)	0
Reorganization items											$ (2,747,239)	$ 2,059	$ (2,745,180)	$ 7,215