Intangible assets and goodwill (Schedule of finite-lived intangible assets) (Details) - USD ($) $ in Thousands |
Apr. 30, 2019 |
Jan. 31, 2019 |
|---|---|---|
| Finite-Lived Intangible Assets [Line Items] | ||
| Intangible assets, gross | $ 138,482 | $ 132,827 |
| Accumulated amortization | (57,045) | (53,161) |
| Intangible assets, net | 81,437 | 79,666 |
| Capitalized software development costs | ||
| Finite-Lived Intangible Assets [Line Items] | ||
| Intangible assets, gross | 44,328 | 40,583 |
| Software | ||
| Finite-Lived Intangible Assets [Line Items] | ||
| Intangible assets, gross | 6,162 | 4,252 |
| Other intangible assets | ||
| Finite-Lived Intangible Assets [Line Items] | ||
| Intangible assets, gross | 2,882 | 2,882 |
| Acquired intangible member assets | ||
| Finite-Lived Intangible Assets [Line Items] | ||
| Intangible assets, gross | $ 85,110 | $ 85,110 |