Note 13 - Common Stock and Earnings Per Share (Details Textual) - USD ($) $ / shares in Units, $ in Millions			12 Months Ended
May 17, 2019	May 16, 2019	Aug. 31, 2019	Aug. 31, 2018	Aug. 31, 2017
Increase in Dividend Rate	12.50%
Common Stock, Dividends, Per Share, Cash Paid	$ 0.72	$ 0.64
Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation			31,644	8,070	49,771
Payment, Tax Withholding, Share-based Payment Arrangement			$ 7.2	$ 1.5	$ 7.8
Share-based Payment Arrangement, Option [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount			11,481	0	704,786
Performance Shares [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount			0	249,443	415,061

This item represents the percentage increase in dividends per share paid.

No definition available.

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- Definition

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

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- Definition

Aggregate dividends paid during the period for each share of common stock outstanding.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

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- Definition

Amount of cash outflow to satisfy grantee's tax withholding obligation for award under share-based payment arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3291-108585

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- Definition

Number of shares used to settle grantee's tax withholding obligation for award under share-based payment arrangement.

+ References

No definition available.

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