PENSION AND OTHER POSTRETIREMENT BENEFITS (Schedule of Unrecognized Benefit Amounts) (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 01, 2018	Mar. 26, 2017
Pension Benefits
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Net actuarial loss (gain), beginning of period	$ 54,235	$ 46,494
Amortization	(301)	(233)
Actuarial loss (gain)	(6,829)	785
Asset loss (gain)	976	(2,652)
Net actuarial loss (gain), end of period	48,081	44,394
Other Benefits
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Net actuarial loss (gain), beginning of period	35	(31)
Amortization	0	0
Actuarial loss (gain)	(48)	(24)
Asset loss (gain)	0	0
Net actuarial loss (gain), end of period	$ (13)	$ (55)