Note 9 - Accrued Retirement Benefits - Net Periodic Cost (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Interest cost	$ 264	$ 309
Expected return on plan assets	(306)	(414)
Amortization of net actuarial loss	156	221
Pension and other postretirement expenses	$ 114	$ 116