Note 6 - Net Income Per Share (Details) - Summary of Earnings Per Share Basic 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, Basic, by Common Class, Including Two Class Method [Line Items]
Net income available to shareholders	$ 34,462	$ 30,760
Allocation of net income for Basic	34,462	30,760
Weighted average number of shares for Basic (in Shares)	20,010	19,955
Common Class A [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Allocation of net income for Basic	27,208	24,191
Weighted average number of shares for Basic (in Shares)	15,029	14,925
Earnings per share for Basic (in Dollars per share)	$ 1.81	$ 1.62
Common Class B [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Allocation of net income for Basic	6,798	6,025
Weighted average number of shares for Basic (in Shares)	4,693	4,647
Earnings per share for Basic (in Dollars per share)	$ 1.45	$ 1.30
Unvested Participating Shares [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Allocation of net income for Basic	$ 456	$ 544
Weighted average number of shares for Basic (in Shares)	288	383