Basis of Presentation and Significant Accounting Policies FX gain (loss) (Details) - Successor [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Foreign Currency Transaction Gain (Loss), before Tax			$ 14,786	$ (29,150)
Loss and Loss Reserves [Member]
Foreign Currency Transaction Gain (Loss), before Tax			17,622	(48,260)
Gain (Loss) on Investments [Member]
Foreign Currency Transaction Gain (Loss), before Tax	$ (2,349)	$ 10,849	(432)	13,632
Premiums Receivable [Member]
Foreign Currency Transaction Gain (Loss), before Tax			(981)	6,945
Unrealized Gains Or (Losses) On Credit Derivative Contracts [Member]
Foreign Currency Transaction Gain (Loss), before Tax			$ (920)	$ (502)