Debt (Premiums, discounts and debt issuance costs) (Details) - USD ($) $ in Thousands		9 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2018
Debt Disclosure [Abstract]
Non-cash expense for write-off of debt issuance costs on Prior Senior Notes	$ 17,756
Non-cash expense for write-off of debt discount costs on Prior Senior Notes	4,014
Non-cash gain for write-off of debt premium on Prior Senior Notes	(4,800)
Total	$ 16,970	$ 0	$ 0