INVENTORIES (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Inventory Disclosure [Abstract]
Inventory valuation reserves	$ 3,993	$ 3,682
Inventories
Raw materials	11,034	14,513
Work-in-process	7,580	8,112
Finished goods	14,798	12,320
Supplies	429	504
Total inventory	$ 33,841	$ 35,449