Property, Plant and Equipment - Summary of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment
Property, plant and equipment, gross	$ 211,334	$ 208,697
Less Accumulated Depreciation	86,572	82,867
Property, plant and equipment, net	124,762	125,830
Land
Property, Plant and Equipment
Property, plant and equipment, gross	11,266	11,237
Buildings and Improvements
Property, Plant and Equipment
Property, plant and equipment, gross	82,156	81,872
Machinery and Equipment
Property, Plant and Equipment
Property, plant and equipment, gross	107,959	105,827
Construction in Progress
Property, Plant and Equipment
Property, plant and equipment, gross	$ 9,953	$ 9,761