Stock-Based Compensation - Performance-based Awards (Details) - USD ($) |
1 Months Ended | 9 Months Ended |
|---|---|---|
Oct. 31, 2016 |
Apr. 30, 2017 |
|
| Stock-based awards, additional disclosure | ||
| Total unrecognized stock-based compensation expense, before income taxes, related to total nonvested stock options and stock awards (in dollars) | $ 10,963,000 | |
| Remaining weighted average period over which unrecognized stock-based compensation expense is expected to be recognized | 20 months | |
| Performance Share Units | ||
| Stock-based awards, additional disclosure | ||
| Maximum attainment of initial grant (as a percent) | 200.00% | |
| TSR-Based | ||
| Stock-based awards, additional disclosure | ||
| Vesting period | 3 years |