Income taxes (Details) - USD ($) $ in Thousands |
3 Months Ended | ||
|---|---|---|---|
Apr. 30, 2019 |
Apr. 30, 2018 |
Jan. 31, 2019 |
|
| Income Tax Disclosure [Abstract] | |||
| Income tax provision (benefit) | $ 9,456 | $ (2,038) | |
| Effective tax rate - (benefit) expense | 18.40% | (9.90%) | |
| Decrease in effective tax rate, primarily due to excess tax benefit on stock-based compensation expense | 4.50% | 31.80% | |
| Unrecognized tax benefits | $ 1,900 | $ 1,700 | |
| Unrecognized tax benefits that would impact the effective tax rate | $ 1,700 | ||
| X | ||||||||||
- Definition Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Percentage of difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying domestic federal statutory income tax rate to pretax income (loss) from continuing operation, attributable to excess tax benefit for share-based compensation cost. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- References No definition available.
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- Definition Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of unrecognized tax benefits. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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