Property, Plant and Equipment - Schedule of Property, Plant and Equipment (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 787,530	$ 787,162
Less: accumulated depreciation	212,647	166,948
Total property, plant and equipment, net	574,883	620,214
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment	3,371	3,371
Plant and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment	768,399	766,263
Buildings
Property, Plant and Equipment [Line Items]
Property, plant and equipment	14,685	14,685
Vehicles
Property, Plant and Equipment [Line Items]
Property, plant and equipment	55	55
Furniture, fixtures & office equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment	629	629
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 391	$ 2,159