Note 12 - Pension Plan - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Amortization of net actuarial loss and prior service cost		$ (2)		$ (4)
Pension Plan [Member]
Service cost	15	16	30	33
Interest cost	18	17	36	33
Expected return on plan assets	(18)	(16)	(36)	(33)
Amortization of net actuarial loss and prior service cost		2		5
Net periodic pension cost	$ 15	$ 19	$ 30	$ 38