Note 10 - Stock-based Compensation - Options/SARs Activity (Details) - Options/SARs [Member] $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended
	Jul. 31, 2017 USD ($) $ / shares shares
Outstanding (in shares) | shares	2,793
Outstanding, weighted average exercise price (in dollars per share) | $ / shares	$ 15.51
Granted (in shares) | shares	380
Granted, weighted average exercise price (in dollars per share) | $ / shares	$ 31.65
Exercised (in shares) | shares	(73)
Exercised, weighted average exercise price (in dollars per share) | $ / shares	$ 10.70
Expired (in shares) | shares	(1)
Expired, weighted average exercise price (in dollars per share) | $ / shares	$ 9.09
Forfeited (in shares) | shares
Forfeited, weighted average exercise price (in dollars per share) | $ / shares
Outstanding (in shares) | shares	3,099
Outstanding, weighted average exercise price (in dollars per share) | $ / shares	$ 17.60
Outstanding at July 31, 2017 (Year)	4 years 146 days
Outstanding at July 31, 2017 | $	$ 40,378
Vested and exercisable (in shares) | shares	2,146
Vested and exercisable, weighted average exercise price (in dollars per share) | $ / shares	$ 14.11
Vested and exercisable, weighted average remaining contractual term (Year)	3 years 109 days
Vested and exercisable, aggregate intrinsic value | $	$ 35,187