Note 11 - Stock-based Compensation - RSUs Activity (Details) - Restricted Stock Units (RSUs) [Member] shares in Thousands	9 Months Ended
	Oct. 31, 2020 $ / shares shares
Restricted stock (in shares) | shares	627
Restricted stock, weighted average grant date fair value (in dollars per share) | $ / shares	$ 39.86
Granted (in shares) | shares	343
Granted, weighted average grant date fair value (in dollars per share) | $ / shares	$ 40.28
Released (in shares) | shares	(248)	[1]
Released, weighted average grant date fair value (in dollars per share) | $ / shares	$ 35.69	[1]
Forfeited (in shares) | shares	(19)
Forfeited, weighted average grant date fair value (in dollars per share) | $ / shares	$ 41.67
Restricted stock (in shares) | shares	703
Restricted stock, weighted average grant date fair value (in dollars per share) | $ / shares	$ 41.49

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