Share-Based Compensation - Unrecognized Compensation Expense and Period for Recognition (Details) $ in Millions |
3 Months Ended |
|---|---|
|
Apr. 30, 2016
USD ($)
| |
| Stock Options [Member] | |
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |
| Unrecognized share-based compensation expense | $ 3.8 |
| Period for recognition | 1 year 9 months 24 days |
| Restricted Stock Units and Restricted Stock [Member] | |
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |
| Unrecognized share-based compensation expense | $ 33.1 |
| Period for recognition | 2 years 2 months 17 days |