Income Taxes - Effective Income Tax Rate - Narrative (Detail) - USD ($) $ in Thousands |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Jan. 29, 2017 |
Jan. 31, 2016 |
Jan. 29, 2017 |
Jan. 31, 2016 |
|
| Income Tax Disclosure [Abstract] | ||||
| Income taxes | $ 643 | $ 2,317 | $ 6,560 | $ 7,398 |
| Effective income tax rate | 28.90% | 35.70% | ||