Note 8 - Benefit Plans - Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Service cost - benefits earned during the period	$ 108	$ 65	$ 57
Interest cost on projected benefit obligation	970	965	988
Expected return on plan assets	(1,717)	(1,218)	(1,188)
Recognized actuarial loss	1,132	1,042	1,027
Settlement loss		435	445
Net periodic pension cost after settlements	$ 493	$ 1,289	$ 1,329