PROPERTY, PLANT AND EQUIPMENT (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Gross property, plant and equipment	$ 321,902	$ 307,746
Less: accumulated depreciation	117,883	113,407
Property, plant and equipment, net	204,019	194,339
Land
Property, Plant and Equipment [Abstract]
Gross property, plant and equipment	11,671	7,965
Building
Property, Plant and Equipment [Abstract]
Gross property, plant and equipment	73,189	67,702
Equipment
Property, Plant and Equipment [Abstract]
Gross property, plant and equipment	214,137	213,909
Construction in progress
Property, Plant and Equipment [Abstract]
Gross property, plant and equipment	$ 22,905	$ 18,170

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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