Note 12 - Retirement Fund and Profit Sharing Plan - Components of SERP Expense (Details) - Supplemental Employee Retirement Plan [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Service cost	$ 126	$ 169
Interest cost	159	135
Net amortization	78	127
Net periodic benefit cost	$ 363	$ 431