Note 6 - Net Income Per Share (Details) - Summary of Earnings Per Share Diluted Two Class Method (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Nov. 30, 2013	Nov. 24, 2012
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
As reported - Basic	$ 34,462	$ 30,760
Add: effect of dilutive potential common shares
Add: Undistributed earnings allocated to unvested participating shares	447	531
Less: Undistributed earnings reallocated to unvested participating shares	(422)	(503)
Diluted EPS – Common Stock	34,031	30,244
Diluted EPS – Common Stock (in Shares)	19,891	19,693
Diluted EPS – Common Stock (in Dollars per share)	$ 1.71	$ 1.54
Common Class A [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
As reported - Basic	27,208	24,191
As reported - Basic (in Shares)	15,029	14,925
As reported - Basic (in Dollars per share)	$ 1.81	$ 1.62
Add: effect of dilutive potential common shares
Effect of dilutive potential common shares (in Shares)	169	121
Diluted EPS – Common Stock	34,031	30,244
Diluted EPS – Common Stock (in Shares)	19,891	19,693
Diluted EPS – Common Stock (in Dollars per share)	$ 1.71	$ 1.54
Common Class B [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
As reported - Basic	6,798	6,025
As reported - Basic (in Shares)	4,693	4,647
As reported - Basic (in Dollars per share)	$ 1.45	$ 1.30
Add: effect of dilutive potential common shares
Effect of dilutive potential common shares	$ 6,798	$ 6,025
Effect of dilutive potential common shares (in Shares)	4,693	4,647