INVENTORIES (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Inventory Disclosure [Abstract]
Inventory valuation reserves	$ 3,036	$ 3,117
Inventories
Raw materials	15,188	15,208
Work-in-process	12,047	11,528
Finished goods	15,463	12,782
Supplies	529	583
Total inventory	$ 43,227	$ 40,101