Summary of Significant Accounting Policies, Schedule of Earnings Per Share, Basic, Two Class Method (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended									12 Months Ended
	Aug. 25, 2012	May 26, 2012		Feb. 25, 2012	Nov. 26, 2011	Aug. 27, 2011	May 28, 2011	Feb. 26, 2011	Nov. 27, 2010	Aug. 25, 2012	Aug. 27, 2011	Aug. 28, 2010
Earnings per share, basic [Abstract]
Net income	$ 22,532	$ 27,459	[1]	$ 19,196	$ 25,802	$ 18,014	$ 18,431	$ 16,277	$ 23,764	$ 94,989	$ 76,486	$ 76,408
Weighted average number of shares - basic										19,916	19,854	19,564
Common Stock [Member]
Earnings per share, basic [Abstract]
Net income										74,643	59,944	59,921
Weighted average number of shares - basic										14,882	14,791	14,570
Earning per share - basic (in amounts per share)										$ 5.02	$ 4.05	$ 4.11
Common Class B [Member]
Earnings per share, basic [Abstract]
Net income										18,630	15,104	15,875
Weighted average number of shares - basic	4,647	4,644		4,640	4,641	4,653	4,656	4,661	4,663	4,643	4,658	4,823
Earning per share - basic (in amounts per share)	$ 0.95	$ 1.16	[1]	$ 0.81	$ 1.09	$ 0.76	$ 0.78	$ 0.69	$ 1.01	$ 4.01	$ 3.24	$ 3.29
Unvested Participating Shares [Member]
Earnings per share, basic [Abstract]
Net income										$ 1,716	$ 1,438	$ 612
Weighted average number of shares - basic										391	405	171

[1] In the third fiscal quarter of 2012, operating results benefited from a settlement of environmental litigation that resulted in the Company recording a $6.7 million pre-tax gain. This gain translated into a $0.21 benefit to the Company's diluted earnings per share.