Note 7 - Summary of Earnings Per Share, Diluted, Two Class Method (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Feb. 27, 2016	Feb. 28, 2015	Feb. 27, 2016	Feb. 28, 2015
Common Class A [Member]
Income allocated to – Basic	$ 18,691	$ 20,182	$ 47,232	$ 49,834
Weighted average number of shares outstanding – Basic (in shares)	15,241	15,185	15,230	15,156
Income per share – Basic (in dollars per share)	$ 1.23	$ 1.33	$ 3.10	$ 3.29
Dilutive potential common shares
Dilutive potential common shares (in shares)	102	139	102	131
Dilutive potential common shares
Income allocated to – Diluted	$ 23,401	$ 25,235	$ 59,141	$ 62,335
Weighted average number of shares outstanding – Diluted (in shares)	20,138	20,065	20,127	20,028
Income per share – Diluted (in dollars per share)	$ 1.16	$ 1.26	$ 2.94	$ 3.11
Common Class B [Member]
Income allocated to – Basic	$ 4,704	$ 5,041	$ 11,896	$ 12,472
Weighted average number of shares outstanding – Basic (in shares)	4,795	4,741	4,795	4,741
Income per share – Basic (in dollars per share)	$ 0.98	$ 1.06	$ 2.48	$ 2.63
Dilutive potential common shares	$ 4,704	$ 5,041	$ 11,896	$ 12,472
Dilutive potential common shares (in shares)	4,795	4,741	4,795	4,741
Dilutive potential common shares	$ 4,704	$ 5,041	$ 11,896	$ 12,472
Income allocated to – Basic	23,498	25,446	59,388	62,859
Add: Undistributed earnings allocated to unvested participating shares	100	217	253	540
Less: Undistributed earnings reallocated to unvested participating shares	(94)	(205)	(240)	(511)
Income allocated to – Diluted	$ 23,401	$ 25,235	$ 59,141	$ 62,335
Weighted average number of shares outstanding – Diluted (in shares)	20,138	20,065	20,127	20,028
Income per share – Diluted (in dollars per share)	$ 1.16	$ 1.26	$ 2.94	$ 3.11