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
	Jul. 01, 2018	Jun. 25, 2017	Jul. 01, 2018	Jun. 25, 2017
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Interest cost	$ 1,365	$ 1,393	$ 2,731	$ 2,786
Estimated return on plan assets	(1,516)	(1,313)	(3,033)	(2,626)
Amortization of net loss	301	233	602	466
Net costs	150	313	300	626
Other Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Interest cost	11	12	23	25
Estimated return on plan assets	0	0	0	0
Amortization of net loss	0	0	0	0
Net costs	$ 11	$ 12	$ 23	$ 25