Note 4 - Periodic Pension Expense - Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Service cost - benefits earned during the period	$ 46	$ 38	$ 138	$ 114
Pension plan termination charge	0	0	6,945	0
Pension Plan [Member]
Interest cost on projected benefit obligation	84	216	424	648
Expected return on plan assets	0	(389)	(597)	(1,167)
Recognized actuarial loss	375	305	1,501	938
Settlement loss	0	82	0	413
Net periodic pension cost after settlements	$ 505	$ 252	$ 8,411	$ 946