Note 16 - Employee Benefit Plans - Components of the Net Periodic Benefit Cost of the Defined Benefit Plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Components of net periodic benefit cost:
Service cost
Interest cost	79	87	83
Expected return on plan assets
Amortization of prior service cost
Amortization of net losses	71	47	59
Net periodic benefit cost	$ 150	$ 134	$ 142