Note 7 - Stock Compensation - Summary of the Status of the Stock Option Plan (Details) - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Balance, vested (in shares)	43,100	34,200
Balance, weighted average exercise price per share (in dollars per share)	$ 28.45	$ 28.43
Balance, non-vested shares (in shares)	1,900	10,800
Balance, weighted average exercise price per share, non-vested (in dollars per share)	$ 30.46	$ 28.86
Balance (in shares)	45,000	45,000
Balance, weighted average exercise price (in dollars per share)	$ 28.54	$ 28.54
Granted, vested (in shares)	0	0
Granted, weighted average exercise price per share (in dollars per share)	$ 0	$ 0
Granted, weighted average exercise price (in dollars per share)	$ 0
Forfeited, vested (in shares)	(35,000)
Forfeited, weighted average exercise price (in dollars per share)	$ 27.99
Forfeited, non-vested shares (in shares)	0	0
Forfeited, weighted average exercise price per share, non-vested (in dollars per share)	$ 0	$ 0
Exercised, vested (in shares)	0
Exercised, weighted average exercise price per share (in dollars per share)	$ 0
Exercised, vested (in shares)	0
Vested, vested (in shares)	1,400	8,900
Vested, weighted average exercise price per share (in dollars per share)	$ 30.58	$ 28.52
Vested, non-vested shares (in shares)	(1,400)	(8,900)
Vested, weighted average exercise price per share, non-vested (in dollars per share)	$ 30.58	$ 28.52
Balance, vested (in shares)	9,500	43,100
Balance, weighted average exercise price per share (in dollars per share)	$ 30.46	$ 28.45
Balance, non-vested shares (in shares)	500	1,900
Balance, weighted average exercise price per share, non-vested (in dollars per share)	$ 30.14	$ 30.46
Balance (in shares)	10,000	45,000
Balance, weighted average exercise price (in dollars per share)	$ 30.45	$ 28.54
Options exercisable at year end, vested (in shares)	0
Options exercisable at year end, weighted average exercise price per share, vested (in dollars per share)	$ 0
Options exercisable at year end (in shares)	0
Remaining contractual life (years), vested (Year)	1 year	2 months 12 days
Remaining contractual life (years), non-vested shares (Year)	1 year 6 months	1 year 2 months 12 days
Remaining contractual life (years), outstanding shares (Year)	1 year	3 months 18 days