Note 6 - Accrued Retirement Benefits - Net Periodic Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Pension and other benefits:
Interest cost	$ 1,034	$ 1,237
Expected return on plan assets	(1,226)	(1,680)
Recognized net actuarial loss	585	933
Settlement expense	7,492	4,252
Pension expense	7,885	4,742
Other changes in plan assets and benefit obligations recognized in comprehensive income:
Net loss (gain)	696	(865)
Amortization of recognized loss	(8,077)	(5,185)
Total recognized gain in comprehensive income	$ (7,381)	$ (6,050)