Note 8 - Employee Benefit Plans - Net Periodic Benefit Costs (Details) - Pension Plan And Supplemental Plan [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Interest cost	$ 846	$ 578
Expected return on plan assets	(688)	(752)
Amortization of net actuarial (gains) losses	(66)	16
Net periodic pension (benefit) cost	$ 92	$ (158)