SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Comprehensive Income (Details) $ in Thousands	6 Months Ended
	Jun. 29, 2019 USD ($)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at the beginning of the period	$ (303,185)
Balance at the end of the period	(303,072)
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at the beginning of the period	(230,261)
Current-period comprehensive income (loss)	3,146
Balance at the end of the period	(227,115)
Gain/(Loss) on Hedging Activities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at the beginning of the period	11,171
Current-period comprehensive income (loss)	(3,033)
Balance at the end of the period	8,138
Defined Benefit Pension Plan
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at the beginning of the period	(84,095)
Current-period comprehensive income (loss)	0
Balance at the end of the period	(84,095)
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at the beginning of the period	(303,185)
Current-period comprehensive income (loss)	113
Balance at the end of the period	$ (303,072)