PENSION AND OTHER POSTRETIREMENT BENEFITS (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 30, 2012	Dec. 25, 2011	Dec. 26, 2010	Dec. 27, 2009
Change in plan assets:
Fair value of plan assets, end of year	$ 92,283	$ 81,193
Pension Plans, Defined Benefit [Member]
Change in projected benefit obligation:
Projected benefit obligation, beginning of year	167,931	155,653
Service cost	51	173	165
Interest cost	8,272	8,213	8,659
Actuarial losses (gains)	24,872	12,072
Benefits paid	(6,692)	(8,180)
Curtailments and settlements	0	0
Projected benefit obligation, end of year	194,434	167,931	155,653
Change in plan assets:
Fair value of plan assets, beginning of year	81,193	84,863
Actual return on plan assets	8,013	(3,247)
Contributions by employer	9,769	7,757
Benefits paid	(6,692)	(8,180)
Curtailments and settlements	0	0
Fair value of plan assets, end of year	92,283	81,193	84,863
Funded status:
Unfunded benefit obligation, end of year	(102,151)	(86,738)
Amounts recognized in the Consolidated Balance Sheets at end of year:
Current liability	(6,656)	(10,993)
Long-term liability	(95,495)	(75,745)
Recognized liability	(102,151)	(86,738)
Amounts recognized in accumulated other comprehensive loss at end of year:
Net actuarial loss (gain)	53,368	31,108	9,708	10,017
Other Postretirement Benefit Plans, Defined Benefit [Member]
Change in projected benefit obligation:
Projected benefit obligation, beginning of year	1,961	2,127
Service cost	0	0
Interest cost	96	112
Actuarial losses (gains)	159	(170)
Benefits paid	0	(108)
Curtailments and settlements	(283)	0
Projected benefit obligation, end of year	1,933	1,961
Change in plan assets:
Fair value of plan assets, beginning of year	0	0
Actual return on plan assets	0	0
Contributions by employer	283	108
Benefits paid	0	(108)
Curtailments and settlements	(283)	0
Fair value of plan assets, end of year	0	0
Funded status:
Unfunded benefit obligation, end of year	(1,933)	(1,961)
Amounts recognized in the Consolidated Balance Sheets at end of year:
Current liability	(158)	(166)
Long-term liability	(1,775)	(1,795)
Recognized liability	(1,933)	(1,961)
Amounts recognized in accumulated other comprehensive loss at end of year:
Net actuarial loss (gain)	$ (49)	$ (217)	$ (47)	$ (50)