Note 9 - Employee Benefit Plans - Net Periodic Benefit Costs (Details) - Pension Plan And Supplemental Plan [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Interest cost	$ 579	$ 543	$ 1,157	$ 1,086
Expected return on plan assets	(751)	(544)	(1,503)	(1,087)
Amortization of net actuarial losses	16	37	32	73
Net periodic pension cost (benefit)	$ (156)	$ 36	$ (314)	$ 72