Note 7 - Share-based Compensation - Stock Option Transactions (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended	12 Months Ended
		Mar. 31, 2022	Dec. 31, 2021
Outstanding, options (in shares)		779,938
Outstanding, weighted average exercise price (in dollars per share)		$ 16.12
Outstanding, weighted average remaining life (Year)		3 years 3 months 29 days	3 years 3 months 7 days
Outstanding, aggregate intrinsic value		$ 2,939	$ 5,097
Granted (in shares)	[1]	103,203
Granted, weighted average exercise price (in dollars per share)		$ 20.13
Exercised (in shares)		(21,108)
Exercised, weighted average exercise price (in dollars per share)		$ 16.25
Lapsed or cancelled (in shares)		(7,252)
Lapsed or cancelled, weighted average exercise price (in dollars per share)		$ 17.85
Outstanding, options (in shares)		854,781	779,938
Outstanding, weighted average exercise price (in dollars per share)		$ 16.59	$ 16.12
Exercisable, options (in shares)		564,335
Exercisable, weighted average exercise price, options (in dollars per share)		$ 13.87
Exercisable, weighted average remaining life, options (Year)		2 years 7 months 28 days
Exercisable, aggregate intrinsic value, options		$ 2,755

[1] The weighted average grant date fair value of stock options granted was $7.84 per share.