BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Property, Plant and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property, plant and equipment
Property, plant and equipment, gross	$ 90,361	$ 73,685
Less accumulated depreciation	(42,326)	(35,282)
Property, plant and equipment, net	48,035	38,403
Depreciation expense	7,921	7,055	$ 6,545
Land
Property, plant and equipment
Property, plant and equipment, gross	981	993
Building and improvements
Property, plant and equipment
Property, plant and equipment, gross	$ 13,054	10,678
Building and improvements | Minimum
Property, plant and equipment
Useful lives	5 years
Building and improvements | Maximum
Property, plant and equipment
Useful lives	39 years
Machinery, equipment, tools and dies
Property, plant and equipment
Property, plant and equipment, gross	$ 60,755	49,083
Machinery, equipment, tools and dies | Minimum
Property, plant and equipment
Useful lives	3 years
Machinery, equipment, tools and dies | Maximum
Property, plant and equipment
Useful lives	15 years
Furniture, fixtures and other
Property, plant and equipment
Property, plant and equipment, gross	$ 15,571	$ 12,931
Furniture, fixtures and other | Minimum
Property, plant and equipment
Useful lives	3 years
Furniture, fixtures and other | Maximum
Property, plant and equipment
Useful lives	10 years