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
	Nov. 26, 2011	Nov. 27, 2010
Common Class A [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Earning per share - basic (in amounts per share)	$ 1.37	$ 1.26
Common Stock options (in shares)	78,000	71,000
Undistributed earnings allocated to unvested participating shares	$ 463	$ 443
Undistributed earnings reallocated to unvested participating shares	(439)	(421)
Diluted EPS - Common Stock	25,350	23,330
Diluted EPS - Common Stock (in dollars per share)	$ 1.30	$ 1.20
Common stock excluded from the calculation of diluted earnings per share (in shares)	18,014	119,088
Diluted EPS - Common Stock (in shares)	19,557,000	19,487,000
Common Class B [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net Income	$ 5,068	$ 4,704
Earning per share - basic (in amounts per share)	$ 1.09	$ 1.01