Note 8 - Accrued Retirement Benefits - Net Periodic Cost (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Interest cost	$ 527	$ 495
Expected return on plan assets	(485)	(578)
Amortization of net loss	211	185
Pension and other postretirement expenses	$ 253	$ 102