Note 4 - Periodic Pension Expense - Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Service cost - benefits earned during the period	$ 38	$ 29
Interest cost on projected benefit obligation	216	271
Expected return on plan assets	(389)	(337)
Recognized actuarial loss	320	325
Settlement loss	138
Net periodic pension cost after settlements	$ 323	$ 288