Basis of Presentation and Significant Accounting Policies Supplemental Cash Flow information (Details) - Successor [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016
Income Taxes Paid	$ 9,718	$ 8,295
Decrease in long-term debt as a result of an exchange for investment securities	0	55,426
Cash and cash equivalents	38,485	118,772	$ 623,703
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	39,619	123,777	624,681	$ 95,898
Long-term Debt [Member]
Interest Paid	100,958	20,496
Variable Interest Entity, Primary Beneficiary [Member]
Restricted cash	$ 1,134	$ 5,005	$ 978