Note 13 - Retirement, Savings and Deferred Compensation Plans - Components of SERP Expense (Details) - Supplemental Employee Retirement Plan [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Service cost	$ 99	$ 92
Interest cost	226	221
Net amortization	20	18
Net periodic benefit cost	$ 345	$ 331