Risk Concentrations (Schedule of Foreign Revenues) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2017	Dec. 31, 2015
Successor
foreign revenue [Line Items]
Revenues	$ 174,097		$ 793,594
Successor | Europe
foreign revenue [Line Items]
Revenues	61,408		388,926
Successor | Asia
foreign revenue [Line Items]
Revenues	55,634		264,503
Successor | North America
foreign revenue [Line Items]
Revenues	43,831		88,145
Successor | Central and South America
foreign revenue [Line Items]
Revenues	13,224		30,982
Successor | Africa
foreign revenue [Line Items]
Revenues	0		14,901
Successor | Brokered Sales
foreign revenue [Line Items]
Revenues	$ 0		$ 6,137
Predecessor
foreign revenue [Line Items]
Revenues		$ 280,879		$ 395,323
Predecessor | Europe
foreign revenue [Line Items]
Revenues		113,888		170,314
Predecessor | Asia
foreign revenue [Line Items]
Revenues		68,536		96,523
Predecessor | North America
foreign revenue [Line Items]
Revenues		56,594		40,315
Predecessor | Central and South America
foreign revenue [Line Items]
Revenues		41,861		55,323
Predecessor | Africa
foreign revenue [Line Items]
Revenues		0		0
Predecessor | Brokered Sales
foreign revenue [Line Items]
Revenues		$ 0		$ 32,848