Note 1 - Summary of Earnings Per Share, Basic, Two Class Method (Details) - USD ($) $ / shares in Units, shares in Thousands	3 Months Ended									12 Months Ended
	Aug. 27, 2016	[1]	May 28, 2016	Feb. 27, 2016	Nov. 28, 2015	Aug. 29, 2015	May 30, 2015	Feb. 28, 2015	Nov. 29, 2014	Aug. 27, 2016	Aug. 29, 2015	Aug. 30, 2014
Common Class A [Member]
Income allocated to – Basic:
Allocation of net income for Basic	$ 28,097,000		$ 23,939,000	$ 18,691,000	$ 28,539,000	$ 23,011,000	$ 25,817,000	$ 20,182,000	$ 29,649,000	$ 99,282,000	$ 98,665,000	$ 94,849,000
Weighted average number of shares outstanding – Basic:
Weighted average number of shares for Basic (in shares)										15,245	15,182	15,080
Earnings per share for Basic:
Earnings per share for Basic (in dollars per share)	$ 1.84		$ 1.57	$ 1.23	$ 1.88	$ 1.51	$ 1.70	$ 1.33	$ 1.96	$ 6.51	$ 6.50	$ 6.29
Common Class B [Member]
Income allocated to – Basic:
Allocation of net income for Basic	$ 7,139,000		$ 6,061,000	$ 4,704,000	$ 7,193,000	$ 5,803,000	$ 6,483,000	$ 5,041,000	$ 7,434,000	$ 25,093,000	$ 24,761,000	$ 23,705,000
Weighted average number of shares outstanding – Basic:
Weighted average number of shares for Basic (in shares)										4,816	4,763	4,711
Earnings per share for Basic:
Earnings per share for Basic (in dollars per share)	$ 1.47		$ 1.26	$ 0.98	$ 1.50	$ 1.21	$ 1.36	$ 1.06	$ 1.57	$ 5.21	$ 5.20	$ 5.03
Unvested Participating Shares [Member]
Income allocated to – Basic:
Allocation of net income for Basic										$ 651,000	$ 873,000	$ 1,371,000
Weighted average number of shares outstanding – Basic:
Weighted average number of shares for Basic (in shares)										107	153	249
Net income	$ 35,494,000		$ 30,144,000	$ 23,498,000	$ 35,890,000	$ 28,941,000	$ 32,499,000	$ 25,446,000	$ 37,413,000	$ 125,026,000	$ 124,299,000	$ 119,925,000
Net income	$ 35,494,000		$ 30,144,000	$ 23,498,000	$ 35,890,000	$ 28,941,000	$ 32,499,000	$ 25,446,000	$ 37,413,000	$ 125,026,000	$ 124,299,000	$ 119,925,000
Weighted average number of shares for Basic (in shares)										20,168	20,098	20,040

[1] In the fourth fiscal quarter of 2016, operating results benefited from a settlement of environmental litigation that resulted in the Company recording a $15.9 million pre-tax gain. This gain translated into a $0.48 benefit to the Company's diluted earnings per share.