Note 5 - Defined Benefit Plan - Defined Benefit Plan Activity (Details) - Pension Plan [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Service cost	$ 324	$ 361	$ 648	$ 722
Interest cost	204	184	408	368
Expected return on plan assets	(629)	(555)	(1,258)	(1,110)
Amortization of prior service cost	0	(3)	0	(6)
Recognized net actuarial loss	110	208	220	416
Net periodic benefit cost	$ 9	$ 195	$ 18	$ 390