Note 8 - Accumulated Other Comprehensive Loss (Details Textual) $ in Thousands	3 Months Ended
Apr. 30, 2020 USD ($)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	$ 0

Amount after tax of reclassification adjustments of other comprehensive income (loss).

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Name:	us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration