PENSION AND OTHER POSTRETIREMENT BENEFITS (Schedule of Net Defined Benefit Pension and Other Postretirement Costs) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 25, 2017	Jun. 26, 2016	Jun. 25, 2017	Jun. 26, 2016
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Interest cost	$ 1,393	$ 1,397	$ 2,786	$ 2,793
Estimated return on plan assets	(1,313)	(1,314)	(2,626)	(2,628)
Amortization of net loss	233	164	466	329
Net costs	313	247	626	494
Other Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Interest cost	12	14	25	26
Estimated return on plan assets	0	0	0	0
Amortization of net loss	0	0	0	0
Net costs	$ 12	$ 14	$ 25	$ 26