Note 4 - Defined Benefit Plan - Defined Benefit Plan Activity (Details) - Pension Plan [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Service cost	$ 203	$ 324	$ 609	$ 972
Interest cost	273	204	819	612
Expected return on plan assets	(518)	(629)	(1,553)	(1,887)
Amortization of prior service cost	0	0	0	0
Recognized net actuarial loss	17	110	52	330
Net periodic benefit (income) cost	$ (25)	$ 9	$ (73)	$ 27