Note 14 - Benefit Plans - Components of Net Periodic (Benefit) Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Interest cost	$ 2,575	$ 2,688	$ 2,747
Expected return on plan assets	(3,525)	(3,011)	(2,868)
Amortization of net loss	802	883	941
Net periodic pension cost (benefit)	$ (148)	$ 560	$ 820