Note 6 - Retirement Plans - Components of Net Periodic Benefit Cost for Pension Plans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Service cost		$ 1,279	$ 3,116	$ 3,886
Interest cost		1,099	4,448	3,336
Expected return on plan assets		(1,123)	(5,114)	(3,410)
Loss amortization		263	1,740	799
Net periodic benefit cost		$ 1,518	$ 4,190	$ 4,611