Property and Equipment, Net - Property and Equipment Table (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 392,930	$ 367,190
Less: Accumulated depreciation	202,680	188,030
Property and equipment, net	190,250	179,160
Land and Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	15,500	14,910
Building [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	73,550	71,100
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 303,880	$ 281,180