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		9 Months Ended
	May 31, 2014	May 25, 2013	May 31, 2014	May 25, 2013
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ 30,944	$ 28,722	$ 91,053	$ 86,124
Allocation of net income for Basic	30,944	28,722	91,053	86,124
Weighted average number of shares for Basic (in Shares)	20,053	19,999	20,038	19,982
Common Class A [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Allocation of net income for Basic	24,493	22,638	71,971	67,793
Weighted average number of shares for Basic (in Shares)	15,102	14,993	15,069	14,960
Earnings per share for Basic (in Dollars per share)	$ 1.62	$ 1.51	$ 4.78	$ 4.53
Common Class B [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Allocation of net income for Basic	6,127	5,647	17,962	16,880
Weighted average number of shares for Basic (in Shares)	4,722	4,675	4,701	4,656
Earnings per share for Basic (in Dollars per share)	$ 1.30	$ 1.21	$ 3.82	$ 3.63
Unvested Participating Shares [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Allocation of net income for Basic	$ 324	$ 437	$ 1,120	$ 1,451
Weighted average number of shares for Basic (in Shares)	229	331	268	366