Recent Accounting Standard Updates - Additional Information (Detail) - USD ($) $ in Thousands |
3 Months Ended | |
|---|---|---|
Apr. 30, 2017 |
Apr. 30, 2016 |
|
| Significant Accounting Policies [Line Items] | ||
| Excess tax benefit due to early adoption | $ 269 | $ 254 |
| ASU 2016-09 [Member] | ||
| Significant Accounting Policies [Line Items] | ||
| Excess tax benefit due to early adoption | $ 1,800 | |