PROPERTY, PLANT AND EQUIPMENT (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Property, plant and equipment
Property, plant and equipment, gross	$ 83,443		$ 83,443		$ 73,685
Less accumulated depreciation	(40,417)		(40,417)		(35,282)
Property, plant and equipment, net	43,026		43,026		38,403
Depreciation expense	1,960	$ 1,817	5,820	$ 5,185
Land
Property, plant and equipment
Property, plant and equipment, gross	985		985		993
Building and improvements
Property, plant and equipment
Property, plant and equipment, gross	11,083		11,083		10,678
Machinery, equipment, tools and dies
Property, plant and equipment
Property, plant and equipment, gross	57,213		57,213		49,083
Furniture, fixtures and other
Property, plant and equipment
Property, plant and equipment, gross	$ 14,162		$ 14,162		$ 12,931