Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 564,581	$ 551,463
Less: accumulated depreciation	(394,397)	(384,425)
Property, plant and equipment, net	170,184	167,038
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	4,116	4,194
Buildings
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	125,393	125,223
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	403,403	397,287
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 31,669	$ 24,759

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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