PENSION AND OTHER POSTRETIREMENT BENEFITS (Schedule of Unrecognized Benefit Amounts) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 26, 2016	Jun. 28, 2015	Jun. 26, 2016	Jun. 28, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Actuarial loss	$ 1,844	$ (8,792)	$ 8,729	$ (6,723)
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			(329)	(357)
Curtailment and settlement adjustments			0	(3,272)
Actuarial loss			12,736	(7,033)
Asset loss (gain)			1,543	(112)
Net actuarial loss (gain), end of period	52,065	33,133	52,065	33,133
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			72	(26)
Asset loss (gain)			0	0
Net actuarial loss (gain), end of period	$ (7)	$ (153)	$ (7)	$ (153)