SIGNIFICANT ACCOUNTING POLICIES - Property (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, plant and equipment:
Depreciation expense	$ 18,991	$ 19,627	$ 20,388
Carrying value of long-lived assets:
Impairment charges of long-lived assets	$ 2,371
Buildings | Minimum
Property, plant and equipment:
Useful lives	20 years
Buildings | Maximum
Property, plant and equipment:
Useful lives	35 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
Carrying value of long-lived assets:
Impairment charges of long-lived assets	$ 2,371	$ 0	$ 0