Employee Benefits and Stock-based Compensation - Restricted Stock and Restricted Stock Units Activities (Detail) - Restricted stock and restricted stock units [Member] - $ / shares |
12 Months Ended | ||
|---|---|---|---|
Jan. 31, 2022 |
Jan. 31, 2021 |
Jan. 31, 2020 |
|
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||
| Shares, Unvested, beginning balance | 2,871,801 | 2,617,266 | 2,395,516 |
| Shares, Granted | 1,213,257 | 1,499,203 | 1,329,288 |
| Shares, Vested | (1,367,309) | (1,162,883) | (1,012,581) |
| Shares, Forfeited | (66,614) | (81,785) | (94,957) |
| Shares, Unvested, ending balance | 2,651,135 | 2,871,801 | 2,617,266 |
| Weighted-Average Grant-Date Fair Value, Unvested, beginning balance | $ 51.73 | $ 50.30 | $ 48.49 |
| Weighted-Average Grant-Date Fair Value, Granted | 128.80 | 53.45 | 54.54 |
| Weighted-Average Grant-Date Fair Value, Vested | 53.85 | 50.53 | 51.24 |
| Weighted-Average Grant-Date Fair Value, Forfeited | 71.59 | 54.48 | 54.26 |
| Weighted-Average Grant-Date Fair Value, Unvested, ending balance | $ 85.41 | $ 51.73 | $ 50.30 |