Note 11 - Changes to Environmental Liabilities (Details) - USD ($)	12 Months Ended
	Aug. 27, 2016	Aug. 29, 2015	Aug. 30, 2014
Beginning balance	$ 23,307,000	$ 19,846,000
Costs incurred for which reserves have been provided	(1,417,000)	(2,014,000)
Insurance proceeds	101,000	121,000
Accretion on environmental contingencies	669,000	603,000	$ 716,000
Changes in discount rates	1,348,000	224,000
Revisions in estimates	2,740,000	4,527,000
Ending balance	$ 26,748,000	$ 23,307,000	$ 19,846,000