Note 9 - Employee Benefit Plans - Net Periodic Benefit Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Interest cost	$ 2,313	$ 2,168	$ 2,907
Administrational expenses	(0)	(0)	49
Pension Plan And Supplemental Plan [Member]
Service cost	0	0	109
Interest cost	2,313	2,168	2,907
Expected return on plan assets	(3,006)	(2,174)	(2,191)
Administrational expenses	0	0	49
Payroll tax of net pension costs	0	0	14
Amortization of net actuarial losses	63	145	(5)
Settlement/curtailment loss	0	0	738
Net periodic pension cost	$ (630)	$ 139	$ 1,621