PENSION AND OTHER POSTRETIREMENT BENEFITS (Schedule of Economic Assumptions and Impact of Change in Discount Rate on Benefit Obligation) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 26, 2016	Jun. 28, 2015	Dec. 27, 2015
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	$ 4,888
Decrease in Discount Rate of 0.25% - Impact on defined benefit obligation for pension benefits	$ 5,197
Pension Benefits [Member]
Assumptions used to measure benefit obligation at end of period:
Discount rate	3.88%		4.47%
Assumptions used to measure net pension and other postretirement cost:
Discount rate	4.47%	4.22%
Expected return on plan assets	5.50%	6.00%
Other Benefits [Member]
Assumptions used to measure benefit obligation at end of period:
Discount rate	3.35%		4.47%
Assumptions used to measure net pension and other postretirement cost:
Discount rate	4.47%	4.22%