Property, Plant and Equipment, Net - Property, Plant and Equipment Details (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	$ 439,681	$ 422,255
Accumulated depreciation	(145,678)	(114,417)
Property, plant and equipment, net	294,003	307,838
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	13,187	12,925
Buildings
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	114,051	112,583
Plant machinery
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	281,786	275,010
Mobile equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	10,366	6,721
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	$ 20,291	$ 15,016