PENSION AND OTHER POSTRETIREMENT BENEFITS (Schedule of Defined Benefit Plan Obligations and Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 25, 2016	Dec. 27, 2015	Dec. 28, 2014
Change in plan assets:
Fair value of plan assets, beginning of year	$ 97,526
Fair value of plan assets, end of year	112,570	$ 97,526
Pension Benefits
Change in projected benefit obligation:
Projected benefit obligation, beginning of year	167,159	165,952
Interest cost	5,571	5,585	$ 7,754
Actuarial losses (gains)	15,745	10,305
Benefits paid	(10,228)	(6,098)
Settlements(a)	0	(8,585)
Projected benefit obligation, end of year	178,247	167,159	165,952
Change in plan assets:
Fair value of plan assets, beginning of year	97,526	96,947
Actual return on plan assets	12,325	4,460
Contributions by employer	12,947	10,802
Benefits paid	(10,228)	(6,098)
Settlements	0	(8,585)
Fair value of plan assets, end of year	112,570	97,526	96,947
Funded status:
Unfunded benefit obligation, end of year	(65,677)	(69,633)
Amounts recognized in the Consolidated and Combined Balance Sheets at end of year:
Current liability	(12,168)	(13,113)
Long-term liability	(53,509)	(56,520)
Recognized liability	(65,677)	(69,633)
Amounts recognized in accumulated other comprehensive loss at end of year:
Net actuarial loss (gain)	54,235	46,494	38,115	$ 43,907
Other Benefits
Change in projected benefit obligation:
Projected benefit obligation, beginning of year	1,648	1,672
Interest cost	51	51
Actuarial losses (gains)	68	46
Benefits paid	0	0
Settlements(a)	(164)	(121)
Projected benefit obligation, end of year	1,603	1,648	1,672
Change in plan assets:
Fair value of plan assets, beginning of year	0	0
Actual return on plan assets	0	0
Contributions by employer	164	121
Benefits paid	0	0
Settlements	(164)	(121)
Fair value of plan assets, end of year	0	0	0
Funded status:
Unfunded benefit obligation, end of year	(1,603)	(1,648)
Amounts recognized in the Consolidated and Combined Balance Sheets at end of year:
Current liability	(149)	(147)
Long-term liability	(1,454)	(1,501)
Recognized liability	(1,603)	(1,648)
Amounts recognized in accumulated other comprehensive loss at end of year:
Net actuarial loss (gain)	$ 35	$ (31)	$ (79)	$ (127)