SIGNIFICANT ACCOUNTING POLICIES - Property (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property, plant and equipment:
Depreciation expense			$ 18,184	$ 18,779	$ 18,669
Impairment charges of long-lived assets				$ 377	$ 1,126
Buildings | Minimum
Property, plant and equipment:
Useful lives			20 years
Buildings | Maximum
Property, plant and equipment:
Useful lives			40 years
Machinery and equipment | Minimum
Property, plant and equipment:
Useful lives			5 years
Machinery and equipment | Maximum
Property, plant and equipment:
Useful lives			20 years
Selling, Marketing, and Administrative Expense
Property, plant and equipment:
Impairment charges of long-lived assets	$ 377	$ 1,126