Property, Plant and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Components of Property, plant and equipment
Property, plant and equipment, gross	$ 589,783		$ 589,783		$ 581,098
Less accumulated depreciation	(104,641)		(104,641)		(80,768)
Property, plant and equipment excluding construction in progress	485,142		485,142		500,330
Construction in progress	10,224		10,224		16,088
Total property, plant and equipment, net	495,366	$ 531,643	495,366	$ 531,643	516,418
Total depreciation expense	8,000	$ 5,700	24,900	$ 18,500
Land
Components of Property, plant and equipment
Property, plant and equipment, gross	13,492		13,492		13,492
Land improvements
Components of Property, plant and equipment
Property, plant and equipment, gross	42,755		42,755		42,148
Buildings
Components of Property, plant and equipment
Property, plant and equipment, gross	140,050		140,050		137,092
Machinery and equipment
Components of Property, plant and equipment
Property, plant and equipment, gross	387,643		387,643		382,740
Vehicles
Components of Property, plant and equipment
Property, plant and equipment, gross	609		609		513
Furniture and office equipment
Components of Property, plant and equipment
Property, plant and equipment, gross	$ 5,234		$ 5,234		$ 5,113