Financial Guarantee Insurance Contracts Financial Guarantee Insurance Contracts Earned Premiums by Geographic Location (Details) - Successor [Member] - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Premiums Earned, Net, Financial Guarantee Insurance Contracts	$ 31,523	$ 52,989	$ 43,152	$ 47,613	$ 49,867	$ 53,218	$ 41,402	$ 52,800	$ 175,277	$ 197,287	$ 312,595
Reportable Geographical Components [Member] | UNITED STATES
Premiums Earned, Net, Financial Guarantee Insurance Contracts									134,099	168,646	229,658
Reportable Geographical Components [Member] | UNITED KINGDOM
Premiums Earned, Net, Financial Guarantee Insurance Contracts									32,928	24,470	68,799
Reportable Geographical Components [Member] | Other International [Member]
Premiums Earned, Net, Financial Guarantee Insurance Contracts									$ 8,250	$ 4,171	$ 14,138