Basis of Presentation and Significant Accounting Policies Supplemental Cash Flow information (Details) - Successor [Member] - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Income Taxes Paid	$ 26,910	$ 16,012
Decrease in long-term debt as a result of an exchange for investment securities	0	55,426
Non Cash Impact of Rehabilitation Exit Transaction	1,918,561	0
Cash and cash equivalents	44,398	54,238	$ 623,703
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	45,450	59,253	624,681	$ 95,898
Long-term Debt [Member]
Interest Paid	157,896	37,471
Variable Interest Entity, Primary Beneficiary [Member]
Restricted cash	$ 1,052	$ 5,015	$ 978