Income Taxes - Additional Information (Detail) - USD ($) |
6 Months Ended | |
|---|---|---|
Jan. 31, 2018 |
Jan. 31, 2017 |
|
| Income Tax Contingency [Line Items] | ||
| Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent | 26.90% | 35.00% |
| Federal Statutory Income Tax Rate, Percent | 21.00% | |
| Provisional Income Tax Expense Resulting from Changes in Tax Legislation (repatriation) | $ 402 | |
| Provisional Income Tax Expense Resulting from Changes in Tax Legislation (net of other disclosures) | 18,832 | |
| Provisional Income Tax Expense Resulting from Changes in Tax Legislation (APB 23) | $ 1,826 | |