Note 11 - Stock-based Compensation - RSUs Activity (Details) - Restricted Stock Units (RSUs) [Member] shares in Thousands	6 Months Ended
	Jul. 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	342
Granted, weighted average grant date fair value (in dollars per share) | $ / shares	$ 40.27
Released (in shares) | shares	(246)	[1]
Released, weighted average grant date fair value (in dollars per share) | $ / shares	$ 35.75	[1]
Forfeited (in shares) | shares	(10)
Forfeited, weighted average grant date fair value (in dollars per share) | $ / shares	$ 40.64
Restricted stock (in shares) | shares	713
Restricted stock, weighted average grant date fair value (in dollars per share) | $ / shares	$ 41.46

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