Segment Information - Reconciliation of Capital Expenditures (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2017
Successor
Segment Reporting Information [Line Items]
Capital Expenditures	$ 16,885	$ 6,014		$ 28,263
Successor | Segment Reconciling Items
Segment Reporting Information [Line Items]
Capital Expenditures	792	671		1,677
Predecessor
Segment Reporting Information [Line Items]
Capital Expenditures			$ 5,422
Predecessor | Segment Reconciling Items
Segment Reporting Information [Line Items]
Capital Expenditures			834
Mining | Successor | Operating Segments
Segment Reporting Information [Line Items]
Capital Expenditures	$ 16,093	$ 5,343		$ 26,586
Mining | Predecessor | Operating Segments
Segment Reporting Information [Line Items]
Capital Expenditures			$ 4,588