Fair Value Measurements - Additional Information (Detail) - USD ($) $ in Thousands |
3 Months Ended | 9 Months Ended | |||
|---|---|---|---|---|---|
Apr. 30, 2020 |
Apr. 30, 2019 |
Apr. 30, 2020 |
Apr. 30, 2019 |
Jul. 31, 2019 |
|
| Disclosure Fair Value Measurements Additional Information [Abstract] | |||||
| Long-term Debt, Fair Value | $ 48,988 | $ 48,988 | $ 51,566 | ||
| Asset Impairment Charges | $ 13,821 | $ 0 | $ 13,821 | $ 0 | |