Note 4 - Periodic Pension Cost - Net Periodic Benefit Cost (Details) - Supplemental Employee Retirement Plan [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Service cost on benefits earned during the period	$ 21	$ 51
Interest cost on projected benefit obligation	159	100
Recognized actuarial loss	55	428
Net periodic pension cost	$ 235	$ 579