Property, Plant and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 334,152	$ 315,980
Depreciation expense	13,400	14,700	$ 14,200
Construction in Process [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 16,392	$ 5,954