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Summary of Weighted-Average Grant-Date Fair Value of Options, Total Intrinsic Value of Options Exercised, and Cash Receipts from Options Exercised (Detail) - USD ($) $ / shares in Units, $ in Thousands | 12 Months Ended
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Aug. 31, 2019 | Aug. 31, 2018 | Aug. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract] |  |  |
Weighted-average fair value of options granted (per share) |  |  | $ 11.88
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value | $ 429 | $ 5,284 | $ 2,208
Proceeds from Stock Options Exercised | $ 1,404 | $ 15,140 | $ 7,762
Expected forfeiture rate | 10.00% | 10.00% | 11.00%

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- Definition Amount of cash inflow from exercise of stock options granted under share-based compensation arrangement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2A -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109197908&loc=SL79508275-113901 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 14 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3255-108585 + Details
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- Definition Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d)(2) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d)(1) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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