Note 7 - Net Income Per Share - Summary of Earnings Per Share, Diluted, Two Class Method (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Nov. 26, 2016	Nov. 28, 2015
Allocation of net income for Basic	$ 28,214	$ 35,890
Add: Undistributed earnings allocated to unvested participating shares	199	154
Less: Undistributed earnings reallocated to unvested participating shares	(189)	(145)
Diluted EPS – Common Stock	$ 28,020	$ 35,741
Diluted EPS – Common Stock (in shares)	20,249	20,132
Diluted EPS – Common Stock (in dollars per share)	$ 1.38	$ 1.78
Common Class A [Member]
Allocation of net income for Basic	$ 22,342	$ 28,539
As reported - Basic (in shares)	15,285	15,218
Earnings per share for Basic (in dollars per share)	$ 1.46	$ 1.88
Dilutive potential common shares	$ 0	$ 0
Dilutive potential common shares (in shares)	117	119
Dilutive potential common shares	$ 0	$ 0
Diluted EPS – Common Stock	$ 28,020	$ 35,741
Diluted EPS – Common Stock (in shares)	20,249	20,132
Diluted EPS – Common Stock (in dollars per share)	$ 1.38	$ 1.78
Common Class B [Member]
Allocation of net income for Basic	$ 5,668	$ 7,193
As reported - Basic (in shares)	4,847	4,795
Earnings per share for Basic (in dollars per share)	$ 1.17	$ 1.50
Dilutive potential common shares	$ 5,668	$ 7,193
Dilutive potential common shares (in shares)	4,847	4,795
Dilutive potential common shares	$ 5,668	$ 7,193