Note 10 - Stock-based Compensation - Options/SARs Activity (Details) - Options/SARs [Member] $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended
	Oct. 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	(127)
Exercised, weighted average exercise price (in dollars per share) | $ / shares	$ 10.54
Expired (in shares) | shares	(10)
Expired, weighted average exercise price (in dollars per share) | $ / shares	$ 9.75
Forfeited (in shares) | shares
Forfeited, weighted average exercise price (in dollars per share) | $ / shares
Outstanding (in shares) | shares	3,036
Outstanding, weighted average exercise price (in dollars per share) | $ / shares	$ 17.75
Outstanding at October 31, 2017 (Year)	4 years 73 days
Outstanding at October 31, 2017 | $	$ 56,056
Vested and exercisable (in shares) | shares	2,085
Vested and exercisable, weighted average exercise price (in dollars per share) | $ / shares	$ 14.23
Vested and exercisable, weighted average remaining contractual term (Year)	3 years 36 days
Vested and exercisable, aggregate intrinsic value | $	$ 45,683