Note 7 - Stock Plans - Summary of SSARs (Details) - Stock Settled Stock Appreciation Rights SSARs [Member] - $ / shares	3 Months Ended		12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Outstanding, awards (in shares)	87,133
Outstanding, weighted average grant date fair value (in dollars per share)	$ 9.69
Outstanding, weighted average remaining contractual term (Year)	4 years 3 months 18 days		4 years 6 months
Granted, awards (in shares)	0
Exercised, awards (in shares)	0	0
Forfeited, awards (in shares)	0
Outstanding, awards (in shares)	87,133		87,133
Outstanding, weighted average grant date fair value (in dollars per share)	$ 9.69		$ 9.69