PROPERTY, PLANT AND EQUIPMENT (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Gross property, plant and equipment	$ 381,202	$ 378,212
Less: accumulated depreciation	154,689	150,116
Property, plant and equipment, net	226,513	228,096
Land
Property, Plant and Equipment [Abstract]
Gross property, plant and equipment	11,923	12,215
Building
Property, Plant and Equipment [Abstract]
Gross property, plant and equipment	87,677	86,873
Equipment
Property, Plant and Equipment [Abstract]
Gross property, plant and equipment	248,326	247,884
Construction in progress
Property, Plant and Equipment [Abstract]
Gross property, plant and equipment	$ 33,276	$ 31,240

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.

+ References

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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