Property, Plant and Equipment - Summary of Property, Plant and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 315,980	$ 310,256
Accumulated depreciation	(212,870)	(206,970)
Total property, plant and equipment, net	103,110	103,286
Building and Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	49,403	47,859
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	228,107	223,450
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	1,620	2,710
Forklifts and Tractors [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	9,799	10,167
Computer Equipment and Software [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	9,680	10,481
Construction in Process [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	5,954	4,172
Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 11,417	$ 11,417