Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands |
3 Months Ended | |
|---|---|---|
Apr. 30, 2018 |
Apr. 30, 2017 |
|
| Earnings Per Share [Abstract] | ||
| Net income | $ 33,699 | $ 30,654 |
| Weighted average common shares - basic | 38,281,000 | 37,251,000 |
| Equity based awards | 280,000 | 217,000 |
| Weighted average common shares - diluted | 38,561,000 | 37,468,000 |
| Basic Earnings Per Share | $ 0.88 | $ 0.82 |
| Diluted Earnings Per Share | $ 0.87 | $ 0.82 |
| Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount | 8,439 | 0 |