PROPERTY, PLANT AND EQUIPMENT (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, plant and equipment
Property, plant and equipment, gross	$ 179,231	$ 184,304
Accumulated depreciation	(122,270)	(122,279)
Property, plant and equipment, net	56,961	62,025
Depreciation expense	6,600	7,000	$ 7,700
Land, buildings and improvements
Property, plant and equipment
Property, plant and equipment, gross	81,311	82,201
Machinery, equipment and fixtures
Property, plant and equipment
Property, plant and equipment, gross	75,177	79,176
Office furniture, equipment and vehicles
Property, plant and equipment
Property, plant and equipment, gross	22,471	22,689
Construction in progress
Property, plant and equipment
Property, plant and equipment, gross	$ 272	$ 238