Note 11 - Stock-based Compensation - PSUs Activity (Details) - Performance Shares [Member] shares in Thousands	6 Months Ended
	Jul. 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)
Released, weighted average grant date fair value (in dollars per share) | $ / shares	$ 39.82
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