HEDGING ACTIVITIES - Gain (Loss) on Derivatives (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 28, 2019	Sep. 29, 2018	Sep. 28, 2019	Sep. 29, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivatives recognized in earnings	$ (453)	$ 758	$ 1,450	$ (501)
Commodity forward contracts | Product cost of sales
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivatives recognized in earnings	(1,329)	717	(1,425)	717
Foreign currency forward contracts | Other income (expenses)
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivatives recognized in earnings	123	230	827	230
Foreign currency forward contracts | Loss from divestiture of grinding media business
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivatives recognized in earnings	0	0	0	(1,215)
Interest rate hedges | Interest expense
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivatives recognized in earnings	(16)	(395)	(48)	(439)
Cross currency swap contracts | Interest expense
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivatives recognized in earnings	$ 769	$ 206	$ 2,096	$ 206