Note 6 - Accrued Retirement Benefits - Net Periodic Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Pension and other benefits:
Interest cost	$ 1,974	$ 2,216
Expected return on plan assets	(2,319)	(2,255)
Recognized net actuarial loss	764	840
Settlement/Curtailment Expense
Pension expense	419	801
Other changes in plan assets and benefit obligations recognized in comprehensive income:
Net gain	2,314	(1,201)
Recognized gain	(764)	(840)
Total recognized gain in comprehensive income	$ 1,550	$ (2,041)