PENSION AND OTHER POSTRETIREMENT BENEFITS (Schedule of Defined Benefit Plan Obligations and Assets) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 27, 2015	Sep. 28, 2014	Sep. 27, 2015	Sep. 28, 2014	Dec. 28, 2014	Dec. 29, 2013
Change in plan assets:
Fair value of plan assets, beginning of period			$ 113,552
Fair value of plan assets, end of period	$ 98,446		98,446
Pension Benefits [Member]
Change in projected benefit obligation:
Projected benefit obligation, beginning of period			190,401	$ 170,030
Interest cost	1,938	$ 2,026	5,815	6,078
Actuarial losses (gains)			981	14,908
Benefits paid			(4,622)	(8,636)
Curtailments and settlements			(14,265)	0
Projected benefit obligation, end of period	178,310	182,380	178,310	182,380
Change in plan assets:
Fair value of plan assets, beginning of period			113,552	108,496
Actual return on plan assets			(3,822)	3,549
Contributions by employer			7,603	11,492
Benefits paid			(4,622)	(8,636)
Curtailments and settlements			(14,265)	0
Fair value of plan assets, end of period	98,446	114,901	98,446	114,901
Funded status:
Unfunded benefit obligation, end of period	(79,864)		(79,864)		$ (76,849)
Amounts recognized in the Condensed Consolidated Balance Sheets at end of period:
Current liability	(9,358)		(9,358)		(9,373)
Long-term liability	(70,506)		(70,506)		(67,476)
Recognized liability	(79,864)		(79,864)		(76,849)
Amounts recognized in accumulated other comprehensive loss at end of period:
Net actuarial loss (gain)	49,558	33,055	49,558	33,055	43,907	$ 16,957
Other Benefits [Member]
Change in projected benefit obligation:
Projected benefit obligation, beginning of period			1,657	1,705
Interest cost	16	20	50	60
Actuarial losses (gains)			(11)	76
Benefits paid			(96)	(111)
Curtailments and settlements			0	0
Projected benefit obligation, end of period	1,600	1,730	1,600	1,730
Change in plan assets:
Fair value of plan assets, beginning of period			0	0
Actual return on plan assets			0	0
Contributions by employer			96	111
Benefits paid			(96)	(111)
Curtailments and settlements			0	0
Fair value of plan assets, end of period	0	0	0	0
Funded status:
Unfunded benefit obligation, end of period	(1,600)		(1,600)		(1,657)
Amounts recognized in the Condensed Consolidated Balance Sheets at end of period:
Current liability	(129)		(129)		(129)
Long-term liability	(1,471)		(1,471)		(1,528)
Recognized liability	(1,600)		(1,600)		(1,657)
Amounts recognized in accumulated other comprehensive loss at end of period:
Net actuarial loss (gain)	$ (138)	$ (50)	$ (138)	$ (50)	$ (127)	$ (126)