Employee and Retiree Benefits (Deferred Compensation Narrative) (Details) (USD $)	12 Months Ended
	Aug. 25, 2012	Aug. 27, 2011	Aug. 28, 2010
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Requiste service period prior to December 1992	20 years
Employer discretionary contribution amount	$ 676,000	$ 676,000	$ 685,000
Key Employees [Member] | Non-Qualified Deferred Compensation Program (1981) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Vesting age	55 years
Requisite service period	5 years
Deferred compensation expense	1,600,000	1,800,000	1,900,000
Deferred compensation liabilities	23,600,000	24,600,000
Officers and Managers [Member] | Supplemental Employee Retirement Plan (SERP) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Deferred compensation liabilities	3,300,000	3,100,000
Contractual amount of years after retirement	15 years
Officers and Key Employees [Member] | Executive Deferred Compensation Plan (2007) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Deferred compensation liabilities	102,000	93,000
Deferred compensation assets	102,000	93,000
Maximum salary deferral	50.00%
Maximum cash incentive award deferral	100.00%
Non-Qualified Share Option Program (2001) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Deferred compensation assets	9,400,000	11,500,000
Deferred share-based compensation liabilities	$ 7,800,000	$ 9,300,000
Additional contribution at initiation	25.00%
Required option exercise period	15 years