Postretirement Benefits (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011 years	Dec. 25, 2010	Dec. 26, 2009
Postretirement Benefits [Abstract]
Years of service that employees were required to have as of October 1, 2001 in order to qualify for postretirement benefits in the future	5.0
Age plus years of service that employees were required to have as of October 1, 2001 in order to qualify for postretirement benefits in the future	65.0
Minimum age that eligible employees are required to have in order to receive post retirement benefits	55.0
Minimum years of service that eligible employees are required to have in order to receive post retirement benefits	10.0
Net actuarial losses recognized in other comprehensive earnings	$ 9,459,000	$ 4,951,000	$ 3,225,000
Tax effect of gain (loss) recognized in other comprehensive earnings	3,655,000	1,913,000	1,246,000
Benefit payments	$ 3,146,000	$ 2,626,000	$ 4,483,000
Accumulation of losses, maximum percentage threshold	10.00%