Note 13 - Stock Option Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Roll Forward
Outstanding-Number of options (in shares)	113,950	116,550	103,350
Exercised-Number of options (in shares)		(19,025)	(9,550)
Forfeited-Number of options (in shares)	(34,150)	(8,575)	(2,250)
Granted-Number of options (in shares)	29,350	25,000	25,000
Outstanding ending-Number of options (in shares)	109,150	113,950	116,550
Exercisable-Number of options (in shares)	43,225
Outstanding-Weighted average exercise price (in dollars per share)	$ 37.58	$ 37.42	$ 36.96
Exercised-Weighted average exercise price (in dollars per share)		30.97	29.39
Forfeited-Weighted average exercise price (in dollars per share)	37.07	35.27	39.86
Granted-Weighted average exercise price (in dollars per share)	37.26	32.50	36.50
Outstanding ending-Weighted average exercise price (in dollars per share)	37.65	$ 37.58	$ 37.42
Exercisable-Weighted average exercise price (in dollars per share)	$ 40.82
Outstanding ending-Weighted average remaining contractual term	2 years 2 months 12 days
Exercisable-Weighted average remaining contractual term	7 months 20 days