Note 6 - Stock-based Compensation - Options/SARs Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2019
Options/SARs [Member]
Outstanding (in shares)	1,349	2,533	3,024
Outstanding, weighted average exercise price (in dollars per share)	$ 24.86	$ 20.81	$ 17.78
Granted (in shares)	0	0	380
Granted, weighted average exercise price (in dollars per share)	$ 0	$ 0	$ 53.50
Exercised (in shares)	(205)	(1,184)	(390)
Exercised, weighted average exercise price (in dollars per share)	$ 12.91	$ 16.19	$ 9.43
Expired (in shares)	0	0	(5)
Expired, weighted average exercise price (in dollars per share)	$ 0	$ 0	$ 9.17
Forfeited (in shares)		0	(476)
Forfeited, weighted average exercise price (in dollars per share)		$ 0	$ 37.14
Outstanding (in shares)	1,144	1,349	2,533
Outstanding, weighted average exercise price (in dollars per share)	$ 27.01	$ 24.86	$ 20.81
Outstanding, weighted average remaining contractual term (Year)	2 years 10 months 24 days
Outstanding, aggregate intrinsic value	$ 40,971
Vested and exercisable (in shares)	1,002
Vested and exercisable, weighted average exercise price (in dollars per share)	$ 24.28
Vested and exercisable, weighted average remaining contractual term (Year)	2 years 6 months
Vested and exercisable, aggregate intrinsic value	$ 38,324
Stock Appreciation Rights (SARs) [Member]
Forfeited (in shares)	0
Forfeited, weighted average exercise price (in dollars per share)	$ 0