Note 9 - Commitments and Contingencies (Details) - Anticipated Payments and Insurance Proceeds of Identified Environmental Remediation Liabilities (USD $) In Thousands, unless otherwise specified	May 31, 2014	Aug. 31, 2013
Anticipated Payments and Insurance Proceeds of Identified Environmental Remediation Liabilities [Abstract]
Estimated costs – current dollars	$ 4,308
Estimated costs – current dollars	2,620
Estimated costs – current dollars	1,887
Estimated costs – current dollars	865
Estimated costs – current dollars	797
Estimated costs – current dollars	12,421
Estimated costs – current dollars	22,898
Estimated insurance proceeds	0
Estimated insurance proceeds	(173)
Estimated insurance proceeds	(159)
Estimated insurance proceeds	(173)
Estimated insurance proceeds	(159)
Estimated insurance proceeds	(1,592)
Estimated insurance proceeds	(2,256)
Net anticipated costs	4,308
Net anticipated costs	2,447
Net anticipated costs	1,728
Net anticipated costs	692
Net anticipated costs	638
Net anticipated costs	10,829
Net anticipated costs	20,642
Effect of inflation	7,591
Effect of discounting	(8,219)
Balance as of May 31, 2014	$ 20,014	$ 19,680