Net Income Per Share, Schedule of Earnings Per Share, Diluted, Two Class Method (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Feb. 25, 2012	Feb. 26, 2011	Feb. 25, 2012	Feb. 26, 2011
Common Class A [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net Income	$ 15,081	$ 12,750	$ 35,341	$ 31,356
Earning per share - basic (in amounts per share)	$ 1.01	$ 0.86	$ 2.38	$ 2.12
Common Stock options (in shares)	92,000	89,000	79,000	75,000
Undistributed earnings allocated to unvested participating shares	337	295	799	737
Undistributed earnings reallocated to unvested participating shares	(320)	(280)	(759)	(700)
Diluted EPS - Common Stock	18,863	15,983	44,213	39,314
Diluted EPS - Common Stock (in dollars per share)	$ 0.96	$ 0.82	$ 2.26	$ 2.02
Common stock excluded from the calculation of diluted earnings per share (in shares)	17,454	19,197	16,369	127,780
Diluted EPS - Common Stock (in shares)	19,605,000	19,528,000	19,575,000	19,503,000
Common Class B [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net Income	$ 3,765	$ 3,218	$ 8,832	$ 7,921
Earning per share - basic (in amounts per share)	$ 0.81	$ 0.69	$ 1.90	$ 1.70
Common Stock options (in shares)	4,640,000	4,661,000	4,640,000	4,662,000