Income taxes (Details) |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jan. 31, 2016 |
Jan. 31, 2015 |
Jan. 31, 2016 |
Jan. 31, 2015 |
|
| Income Tax Disclosure [Abstract] | ||||
| Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent | 2.90% | 2.70% | 2.50% | 2.50% |
| Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent | 34.00% | |||
| X | ||||||||||
- Definition Percentage of domestic federal statutory tax rate applicable to pretax income (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to state and local income tax expense (benefit), net of federal tax expense (benefit). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- References No definition available.
|