Note 11 - Stock-based Compensation - Options/SARs Activity (Details) - Options/SARs [Member] $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended
	Oct. 31, 2018 USD ($) $ / shares shares
Outstanding (in shares) | shares	3,024
Outstanding, weighted average exercise price (in dollars per share) | $ / shares	$ 17.78
Granted (in shares) | shares	380
Granted, weighted average exercise price (in dollars per share) | $ / shares	$ 53.50
Exercised (in shares) | shares	(386)
Exercised, weighted average exercise price (in dollars per share) | $ / shares	$ 9.41
Expired (in shares) | shares	(5)
Expired, weighted average exercise price (in dollars per share) | $ / shares	$ 8.97
Forfeited (in shares) | shares	(476)
Forfeited, weighted average exercise price (in dollars per share) | $ / shares	$ 37.14
Outstanding (in shares) | shares	2,537
Outstanding, weighted average exercise price (in dollars per share) | $ / shares	$ 20.80
Outstanding at October 31, 2018 (Year)	3 years 292 days
Outstanding at October 31, 2018 | $	$ 53,606
Vested and exercisable (in shares) | shares	2,062
Vested and exercisable, weighted average exercise price (in dollars per share) | $ / shares	$ 17.03
Vested and exercisable, weighted average remaining contractual term (Year)	3 years 36 days
Vested and exercisable, aggregate intrinsic value | $	$ 49,271