Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Percentage of vesting of award under share-based payment arrangement.

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Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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Equity impact of the value of stock that has been repurchased during the period and has not been retired and is not held in treasury. Some state laws may mandate the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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Stockholders' Equity (Detail) - USD ($)	3 Months Ended
Stockholders' Equity (Detail) - USD ($)	Oct. 31, 2019	Oct. 31, 2018	Jun. 19, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock repurchased (in shares)	0	0
Stock repurchased	$ 0	$ 0
Performance Shares (PSUs) \| Share-based Compensation Award, Tranche Two \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentages	50.00%
Performance Shares (PSUs) \| Share-based Compensation Award, Tranche Two \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentages	150.00%
Performance Shares (PSUs) \| Share-based Compensation Award, Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentages	50.00%
Performance Shares (PSUs) \| Share-based Compensation Award, Tranche Three
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentages	15000.00%
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 5,013,000	$ 4,530,000
Stock repurchase program authorized amount			$ 250,000,000