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		9 Months Ended
	May 31, 2014	May 25, 2013	May 31, 2014	May 25, 2013
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
As reported - Basic	$ 30,944	$ 28,722	$ 91,053	$ 86,124
Add: Undistributed earnings allocated to unvested participating shares	317	426	1,095	1,415
Less: Undistributed earnings reallocated to unvested participating shares	(300)	(404)	(1,036)	(1,341)
Diluted EPS – Common Stock	30,637	28,307	89,992	84,747
Diluted EPS – Common Stock (in Shares)	19,977	19,820	19,921	19,751
Diluted EPS – Common Stock (in Dollars per share)	$ 1.53	$ 1.43	$ 4.52	$ 4.29
Common Class A [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
As reported - Basic	24,493	22,638	71,971	67,793
As reported - Basic (in Shares)	15,102	14,993	15,069	14,960
As reported - Basic (in Dollars per share)	$ 1.62	$ 1.51	$ 4.78	$ 4.53
Effect of dilutive potential common shares (in Shares)	153	152	151	135
Diluted EPS – Common Stock	30,637	28,307	89,992	84,747
Diluted EPS – Common Stock (in Shares)	19,977	19,820	19,921	19,751
Diluted EPS – Common Stock (in Dollars per share)	$ 1.53	$ 1.43	$ 4.52	$ 4.29
Common Class B [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
As reported - Basic	6,127	5,647	17,962	16,880
As reported - Basic (in Shares)	4,722	4,675	4,701	4,656
As reported - Basic (in Dollars per share)	$ 1.30	$ 1.21	$ 3.82	$ 3.63
Effect of dilutive potential common shares	$ 6,127	$ 5,647	$ 17,962	$ 16,880
Effect of dilutive potential common shares (in Shares)	4,722	4,675	4,701	4,656