Note 11 - Stock-based Compensation - PSUs Activity (Details) - Performance Shares [Member] shares in Thousands	9 Months Ended
	Oct. 31, 2020 $ / shares shares
Restricted stock (in shares) | shares	90
Restricted stock, weighted average grant date fair value (in dollars per share) | $ / shares	$ 39.82
Granted (in shares) | shares	93
Granted, weighted average grant date fair value (in dollars per share) | $ / shares	$ 40.54
Released (in shares) | shares	(21)	[1]
Released, weighted average grant date fair value (in dollars per share) | $ / shares	$ 39.82	[1]
Forfeited (in shares) | shares	(9)
Forfeited, weighted average grant date fair value (in dollars per share) | $ / shares	$ 39.82
Restricted stock (in shares) | shares	153
Restricted stock, weighted average grant date fair value (in dollars per share) | $ / shares	$ 40.26

[1] The number of PSUs released includes shares withheld on behalf of employees to satisfy the minimum statutory tax withholding requirements.