Property and Equipment, Net - Property and Equipment Table (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 399,120	$ 392,930
Less: Accumulated depreciation	212,050	202,680
Property and equipment, net	187,070	190,250
Land and Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	15,410	15,500
Building [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	74,310	73,550
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 309,400	$ 303,880