Property and Equipment, Net - Property and Equipment Table (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 397,760	$ 392,930
Less: Accumulated depreciation	209,320	202,680
Property and equipment, net	188,440	190,250
Land and Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	15,540	15,500
Building [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	75,850	73,550
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 306,370	$ 303,880