Note 9 - Accrued Retirement Benefits - Net Periodic Cost (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Interest cost	$ 203	$ 264	$ 608	$ 793
Expected return on plan assets	(165)	(306)	(491)	(918)
Amortization of net loss	83	156	247	468
Pension and other postretirement expenses	$ 121	$ 114	$ 364	$ 343