SIGNIFICANT ACCOUNTING POLICIES - Property, Plant and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment
Property, plant and equipment	$ 180,278	$ 174,741
Land
Property, Plant and Equipment
Property, plant and equipment	3,634	3,551
Buildings and improvements
Property, Plant and Equipment
Property, plant and equipment	$ 59,556	58,069
Buildings and improvements | Minimum
Property, Plant and Equipment
Estimated useful life	15 years
Buildings and improvements | Maximum
Property, Plant and Equipment
Estimated useful life	40 years
Manufacturing equipment and tooling
Property, Plant and Equipment
Property, plant and equipment	$ 72,992	72,081
Manufacturing equipment and tooling | Minimum
Property, Plant and Equipment
Estimated useful life	3 years
Manufacturing equipment and tooling | Maximum
Property, Plant and Equipment
Estimated useful life	15 years
Furniture, fixtures and computer equipment
Property, Plant and Equipment
Property, plant and equipment	$ 22,194	21,683
Furniture, fixtures and computer equipment | Minimum
Property, Plant and Equipment
Estimated useful life	3 years
Furniture, fixtures and computer equipment | Maximum
Property, Plant and Equipment
Estimated useful life	10 years
Other
Property, Plant and Equipment
Property, plant and equipment	$ 7,261	6,041
Other | Minimum
Property, Plant and Equipment
Estimated useful life	3 years
Other | Maximum
Property, Plant and Equipment
Estimated useful life	10 years
Construction in process
Property, Plant and Equipment
Property, plant and equipment	$ 14,641	$ 13,316