Postretirement Benefits (Change In Benefit Obligation And Fair Value Of Plan Assets) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 25, 2010	Dec. 26, 2009
Defined Benefit Plan Disclosure [Line Items]
Benefit payments	$ (3,146,000)	$ (2,626,000)	$ (4,483,000)
Unfunded status of the plan as of end of year	107,624,000	94,776,000
Current liability	4,029,000	3,841,000
Noncurrent liability	103,595,000	90,935,000
Total recognized liability	107,624,000	94,776,000
Change In Benefit Obligation [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation as of beginning of year	94,776,000	86,890,000
Service cost	163,000	175,000
Interest cost	5,301,000	5,291,000
Actuarial loss	10,530,000	5,046,000
Benefit payments	(3,146,000)	(2,626,000)
Benefit obligation as of end of year	107,624,000	94,776,000
Change In Fair Value Of Plan Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets as of beginning of year
Employer contributions	3,146,000	2,626,000
Benefit payments	(3,146,000)	(2,626,000)
Fair value of plan assets as of end of year