PENSION AND OTHER POSTRETIREMENT BENEFITS (Schedule of Unrecognized Benefit Amounts) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jul. 01, 2018	Jun. 25, 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	(602)	(466)
Actuarial loss (gain)	(9,465)	8,885
Asset loss (gain)	2,936	(4,515)
Net actuarial loss (gain), end of period	47,104	50,398
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)	(62)	101
Asset loss (gain)	0	0
Net actuarial loss (gain), end of period	$ (27)	$ 70