Basis of presentation (Details) - USD ($) $ in Thousands |
Jan. 31, 2021 |
Jan. 31, 2020 |
|---|---|---|
| Reclassifications [Line Items] | ||
| Long-term debt and finance lease liabilities | $ 4,864 | $ 2,324 |
| Reclassification from current finance lease liabilities | (3,820) | |
| Long term debt and finance lease liabilities | 6,471 | 21,540 |
| Reclassification of long-term finance leases | (5,882) | |
| Revision of Prior Period, Adjustment | ||
| Reclassifications [Line Items] | ||
| Long-term debt and finance lease liabilities | 2,300 | |
| Reclassification from current finance lease liabilities | 2,300 | |
| Long term debt and finance lease liabilities | $ 2,100 | |
| Reclassification of long-term finance leases | $ 2,100 |