PENSION AND OTHER POSTRETIREMENT BENEFITS (Schedule of Unrecognized Benefit Amounts) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 25, 2016	Sep. 27, 2015	Sep. 25, 2016	Sep. 27, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Actuarial loss (gain)	$ (1,878)	$ 10,234	$ 6,851	$ 3,511
Pension Benefits [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Net actuarial loss (gain), beginning of period			38,115	43,907
Amortization			(494)	(536)
Curtailment and settlement adjustments			0	(3,629)
Actuarial loss (gain)			12,233	981
Asset loss (gain)			(828)	8,835
Net actuarial loss (gain), end of period	49,026	49,558	49,026	49,558
Other Benefits [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Net actuarial loss (gain), beginning of period			(79)	(127)
Amortization			0	0
Curtailment and settlement adjustments			0	0
Actuarial loss (gain)			95	(11)
Asset loss (gain)			0	0
Net actuarial loss (gain), end of period	$ 16	$ (138)	$ 16	$ (138)