Note 4 - Periodic Pension Cost - Net Periodic Benefit Cost (Details) - Supplemental Employee Retirement Plan [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Service cost on benefits earned during the period	$ 0	$ 51	$ 21	$ 153
Interest cost on projected benefit obligation	159	100	477	300
Recognized actuarial loss	55	428	165	1,284
Net periodic pension cost	$ 214	$ 579	$ 663	$ 1,737