Fair Value of TSR Performance-Based Awards Valuation Assumption (Parenthetical) (Detail) |
3 Months Ended | 9 Months Ended | ||||
|---|---|---|---|---|---|---|
Apr. 30, 2017 |
Apr. 30, 2016 |
Apr. 30, 2017 |
Apr. 30, 2016 |
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| Restricted Stock Units (RSUs) | ||||||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||||
| Expected annual dividend yield | [1] | 0.00% | 0.00% | 0.00% | 0.00% | |
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