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		6 Months Ended
	Mar. 01, 2014	Feb. 23, 2013	Mar. 01, 2014	Feb. 23, 2013
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
As reported - Basic	$ 25,647	$ 26,642	$ 60,109	$ 57,402
Add: Undistributed earnings allocated to unvested participating shares	329	457	776	989
Less: Undistributed earnings reallocated to unvested participating shares	(311)	(433)	(734)	(937)
Diluted EPS – Common Stock	25,326	26,196	59,357	56,440
Diluted EPS – Common Stock (in Shares)	19,924	19,747	19,897	19,714
Diluted EPS – Common Stock (in Dollars per share)	$ 1.27	$ 1.33	$ 2.98	$ 2.86
Common Class A [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
As reported - Basic	20,267	20,963	47,479	45,155
As reported - Basic (in Shares)	15,077	14,962	15,053	14,943
As reported - Basic (in Dollars per share)	$ 1.34	$ 1.40	$ 3.15	$ 3.02
Effect of dilutive potential common shares (in Shares)	160	138	154	124
Diluted EPS – Common Stock	25,326	26,196	59,357	56,440
Diluted EPS – Common Stock (in Shares)	19,924	19,747	19,897	19,714
Diluted EPS – Common Stock (in Dollars per share)	$ 1.27	$ 1.33	$ 2.98	$ 2.86
Common Class B [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
As reported - Basic	5,041	5,209	11,836	11,233
As reported - Basic (in Shares)	4,687	4,647	4,690	4,647
As reported - Basic (in Dollars per share)	$ 1.08	$ 1.12	$ 2.52	$ 2.42
Effect of dilutive potential common shares	$ 5,041	$ 5,209	$ 11,836	$ 11,233
Effect of dilutive potential common shares (in Shares)	4,687	4,647	4,690	4,647