PROPERTY, PLANT AND EQUIPMENT (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Property, plant and equipment [Abstract]
Property, plant and equipment, gross	$ 149,624		$ 149,624		$ 149,104
Accumulated depreciation	(104,677)		(104,677)		(100,349)
Property, plant and equipment, net	44,947		44,947		48,755
Depreciation expense	3,400	$ 3,700	7,000	$ 7,400
Land [Member]
Property, plant and equipment [Abstract]
Property, plant and equipment, gross	2,250		2,250		2,234
Buildings and Improvements [Member]
Property, plant and equipment [Abstract]
Property, plant and equipment, gross	30,444		30,444		30,061
Machinery and Equipment [Member]
Property, plant and equipment [Abstract]
Property, plant and equipment, gross	114,628		114,628		113,780
Construction in Progress [Member]
Property, plant and equipment [Abstract]
Property, plant and equipment, gross	$ 2,302		$ 2,302		$ 3,029