PENSION AND OTHER POSTRETIREMENT BENEFITS (Schedule of Economic Assumptions and Impact of Change in Discount Rate on Benefit Obligation) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 26, 2017	Mar. 27, 2016	Dec. 25, 2016
Assumptions used to measure net pension and other postretirement cost:
Increase in Discount Rate of 0.25% - Impact on defined benefit obligation for pension benefits	$ (4,617)
Decrease in Discount Rate of 0.25% - Impact on defined benefit obligation for pension benefits	$ 4,909
Pension Benefits
Assumptions used to measure benefit obligation at end of period:
Discount rate	4.29%		4.31%
Assumptions used to measure net pension and other postretirement cost:
Discount rate	4.31%	4.47%
Expected return on plan assets	5.50%	5.50%
Other Benefits
Assumptions used to measure benefit obligation at end of period:
Discount rate	3.78%		3.81%
Assumptions used to measure net pension and other postretirement cost:
Discount rate	3.81%	4.47%