Income taxes (Component of income tax (benefit) expense from continuing operations) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Mar. 21, 2017	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2016
Current income taxes
Federal		$ (162)	$ (77)
State		(187)	0
Total current income taxes		(349)	(77)
Deferred income taxes
Federal		0	0
State		0	0
Total deferred income taxes		0	0
Income tax (benefit) expense		$ (349)	$ (77)
Predecessor
Current income taxes
Federal	$ 0			$ (10)
State	37			(92)
Total current income taxes	37			(102)
Deferred income taxes
Federal	0			0
State	0			0
Total deferred income taxes	0			0
Income tax (benefit) expense	$ 37			$ (102)