Note 5 - Employee Benefit Plan - Net Periodic Pension Costs (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Interest cost	$ 36	$ 41	$ 72	$ 82
Expected return on plan assets	(174)	(157)	(348)	(314)
Recognized net actuarial (gain)/loss	9	7	18	14
Net periodic benefit cost	$ (129)	$ (109)	$ (258)	$ (218)