PENSION AND OTHER POSTRETIREMENT BENEFITS (Details 6) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 30, 2012	Dec. 25, 2011	Dec. 26, 2010
Pension Plans, Defined Benefit [Member]
Net actuarial loss (gain), beginning of year	$ 31,108	$ 9,708	$ 10,017
Amortization	(465)	(96)	(1)
Curtailment and settlement adjustments	0	0	(1,768)
Actuarial loss (gain)	24,872	12,072	6,675
Asset loss (gain)	(2,147)	9,424	(5,215)
Net actuarial loss (gain), end of year	53,368	31,108	9,708
Net prior service cost, beginning of year	0	19	58
Amortization	0	(19)	(39)
Net prior service cost, end of year	0	0	19
Other Postretirement Benefit Plans, Defined Benefit [Member]
Net actuarial loss (gain), beginning of year	(217)	(47)	(50)
Amortization	2	0	0
Curtailment and settlement adjustments	7	0	0
Actuarial loss (gain)	159	(170)	3
Asset loss (gain)	0	0	0
Net actuarial loss (gain), end of year	(49)	(217)	(47)
Net prior service cost, beginning of year	0	0	0
Amortization	0	0	0
Net prior service cost, end of year	$ 0	$ 0	$ 0