PENSION AND OTHER POSTRETIREMENT BENEFITS (Schedule of Unrecognized Benefit Amounts) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 28, 2021	Mar. 29, 2020
Pension Benefits
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Net actuarial loss, beginning of period	$ 95,522	$ 58,239
Amortization	(570)	(376)
Actuarial gain	(27,980)	(29,447)
Asset loss (gain)	(1,505)	40,578
Currency translation loss (gain)	364	(303)
Net actuarial loss, end of period	65,831	68,691
Other Benefits
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Net actuarial loss, beginning of period	174	91
Amortization	(1)	0
Actuarial gain	(53)	(17)
Asset loss (gain)	0	0
Currency translation loss (gain)	0	0
Net actuarial loss, end of period	$ 120	$ 74