Note 4 - Defined Benefit Plan - Defined Benefit Plan Activity (Details) - Pension Plan [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Service cost	$ 203	$ 324	$ 406	$ 648
Interest cost	273	204	546	408
Expected return on plan assets	(518)	(629)	(1,036)	(1,258)
Amortization of prior service cost	0	0	0	0
Recognized net actuarial loss	17	110	34	220
Net periodic benefit (income) cost	$ (25)	$ 9	$ (50)	$ 18