PROPERTY, PLANT AND EQUIPMENT (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Property, plant and equipment
Property, plant and equipment, gross	$ 188,693	$ 183,786
Accumulated depreciation	(122,355)	(117,912)
Property, plant and equipment, net	66,338	65,874
Land, buildings and improvements
Property, plant and equipment
Property, plant and equipment, gross	85,858	83,119
Machinery, equipment and fixtures
Property, plant and equipment
Property, plant and equipment, gross	79,445	78,003
Office furniture, equipment and vehicles
Property, plant and equipment
Property, plant and equipment, gross	22,679	22,265
Construction in progress
Property, plant and equipment
Property, plant and equipment, gross	$ 711	$ 399