BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Property, Plant and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property, plant and equipment
Property, plant and equipment, gross	$ 118,040	$ 104,034
Less accumulated depreciation	(62,612)	(51,026)
Property, plant and equipment, net	55,428	53,008
Depreciation expense	10,057	9,139	$ 7,921
Land
Property, plant and equipment
Property, plant and equipment, gross	999	977
Building and improvements
Property, plant and equipment
Property, plant and equipment, gross	$ 14,169	13,366
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	$ 79,738	58,358
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
Construction work in progress
Property, plant and equipment
Property, plant and equipment, gross	$ 6,821	15,536
Furniture, fixtures and other
Property, plant and equipment
Property, plant and equipment, gross	$ 16,313	$ 15,797
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