Note 9 - Accrued Retirement Benefits - Net Periodic Cost (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Interest cost	$ 264	$ 309	$ 529	$ 618
Expected return on plan assets	(306)	(418)	(612)	(836)
Amortization of net loss	156	221	312	442
Pension and other postretirement expenses	$ 114	$ 112	$ 229	$ 224