PENSION AND OTHER POSTRETIREMENT BENEFITS (Schedule of Defined Benefit Plan Obligations and Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2018	Dec. 31, 2017	Dec. 25, 2016	Dec. 27, 2015
Change in plan assets:
Fair value of plan assets, beginning of year	$ 112,570
Fair value of plan assets, end of year	102,414	$ 112,570
Pension Benefits
Change in projected benefit obligation:
Projected benefit obligation, beginning of year	178,247	167,159
Interest cost	5,463	5,571	$ 5,585
Actuarial losses (gains)	(15,635)	15,745
Benefits paid	(10,456)	(10,228)
Settlements(a)	0	0
Projected benefit obligation, end of year	157,619	178,247	167,159
Change in plan assets:
Fair value of plan assets, beginning of year	112,570	97,526
Actual return on plan assets	(10,881)	12,325
Contributions by employer	11,181	12,947
Benefits paid	(10,456)	(10,228)
Settlements	0	0
Fair value of plan assets, end of year	102,414	112,570	97,526
Funded status:
Unfunded benefit obligation, end of year	(55,205)	(65,677)
Amounts recognized in the Consolidated Balance Sheets at end of year:
Current liability	(8,267)	(12,168)
Long-term liability	(46,938)	(53,509)
Recognized liability	(55,205)	(65,677)
Amounts recognized in accumulated other comprehensive loss at end of year:
Net actuarial loss (gain)	54,343	54,235	46,494	$ 38,115
Other Benefits
Change in projected benefit obligation:
Projected benefit obligation, beginning of year	1,603	1,648
Interest cost	46	51
Actuarial losses (gains)	(72)	68
Benefits paid	0	0
Settlements(a)	(115)	(164)
Projected benefit obligation, end of year	1,462	1,603	1,648
Change in plan assets:
Fair value of plan assets, beginning of year	0	0
Actual return on plan assets	0	0
Contributions by employer	115	164
Benefits paid	0	0
Settlements	(115)	(164)
Fair value of plan assets, end of year	0	0	0
Funded status:
Unfunded benefit obligation, end of year	(1,462)	(1,603)
Amounts recognized in the Consolidated Balance Sheets at end of year:
Current liability	(149)	(149)
Long-term liability	(1,313)	(1,454)
Recognized liability	(1,462)	(1,603)
Amounts recognized in accumulated other comprehensive loss at end of year:
Net actuarial loss (gain)	$ (34)	$ 35	$ (31)	$ (79)