Note 6 - Defined Benefit Pension Plan (Details) - Components of Net Periodic Pension Cost - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Components of Net Periodic Pension Cost [Abstract]
Service cost including expected expenses and net of expected plan participant contributions	$ 297	$ 279	$ 892	$ 837
Interest cost	351	352	1,055	1,056
Expected return on plan assets	(770)	(752)	(2,314)	(2,256)
Amortization of prior service cost		4		11
Net pension credit	$ (122)	$ (117)	$ (367)	$ (352)