Note 5 - Share-based Compensation - Stock Option Activity Under Equity Incentive Plans and Director Plan (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Exercised, number of options (in shares)	75,283	20,938
Performance based Stock Options [Member]
Beginning balance, outstanding, number of options (in shares)	0
Beginning balance, outstanding, weighted average exercise price (in dollars per share)	$ 0
Granted, number of options (in shares)	404,833		0
Granted, weighted average exercise price (in dollars per share)	$ 39.54
Exercised, number of options (in shares)	0
Exercised, weighted average exercise price (in dollars per share)	$ 0
Forfeited, number of options (in shares)	0
Forfeited, weighted average exercise price (in dollars per share)	$ 0
Ending balance, outstanding, number of options (in shares)	404,833		0
Ending balance, outstanding, weighted average exercise price (in dollars per share)	$ 39.54		$ 0
Outstanding, weighted average remaining contractual term (Year)	5 years 9 months 18 days
Outstanding, aggregate intrinsic value	$ 28
Exercisable, number of options (in shares)	0
Weighted average exercise price (in dollars per share)	$ 0
Service based Stock Options [Member]
Beginning balance, outstanding, number of options (in shares)	569,168
Beginning balance, outstanding, weighted average exercise price (in dollars per share)	$ 35.72
Granted, number of options (in shares)	0	59,429
Granted, weighted average exercise price (in dollars per share)	$ 0
Exercised, number of options (in shares)	75,283
Exercised, weighted average exercise price (in dollars per share)	$ 23.27
Forfeited, number of options (in shares)	37,556
Forfeited, weighted average exercise price (in dollars per share)	$ 45.53
Ending balance, outstanding, number of options (in shares)	456,329		569,168
Ending balance, outstanding, weighted average exercise price (in dollars per share)	$ 36.96		$ 35.72
Outstanding, weighted average remaining contractual term (Year)	5 years 6 months 25 days
Outstanding, aggregate intrinsic value	$ 2,750
Exercisable, number of options (in shares)	307,070
Weighted average exercise price (in dollars per share)	$ 33.45
Exercisable, weighted average remaining contractual term (Year)	4 years 4 months 28 days
Exercisable, aggregate intrinsic value	$ 2,725