Debt (Prior senior notes) (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2015	Mar. 21, 2017	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Gains on extinguishment of debt			$ (635)	$ 0
Predecessor
Debt Instrument [Line Items]
Gains on extinguishment of debt		$ 0			$ 0
Senior Notes
Debt Instrument [Line Items]
Senior note repurchase amount	$ 42,045					$ 42,045
Debt instrument cash paid for repurchase	$ 9,995
Gains on extinguishment of debt						$ 31,590
Senior Notes | Predecessor
Debt Instrument [Line Items]
Interest expense		$ 22,582			$ 65,225