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		6 Months Ended
	Mar. 01, 2014	Feb. 23, 2013	Mar. 01, 2014	Feb. 23, 2013
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ 25,647	$ 26,642	$ 60,109	$ 57,402
Allocation of net income for Basic	25,647	26,642	60,109	57,402
Weighted average number of shares for Basic (in Shares)	20,052	19,992	20,031	19,973
Common Class A [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Allocation of net income for Basic	20,267	20,963	47,479	45,155
Weighted average number of shares for Basic (in Shares)	15,077	14,962	15,053	14,943
Earnings per share for Basic (in Dollars per share)	$ 1.34	$ 1.40	$ 3.15	$ 3.02
Common Class B [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Allocation of net income for Basic	5,041	5,209	11,836	11,233
Weighted average number of shares for Basic (in Shares)	4,687	4,647	4,690	4,647
Earnings per share for Basic (in Dollars per share)	$ 1.08	$ 1.12	$ 2.52	$ 2.42
Unvested Participating Shares [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Allocation of net income for Basic	$ 339	$ 470	$ 794	$ 1,014
Weighted average number of shares for Basic (in Shares)	288	383	288	383