Note 9 - Accrued Retirement Benefits - Net Periodic Cost (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Interest cost	$ 203	$ 264	$ 406	$ 529
Expected return on plan assets	(164)	(306)	(328)	(612)
Amortization of net loss	82	156	165	312
Pension and other postretirement expenses	$ 121	$ 114	$ 243	$ 229