Note 12 - Defined Benefit Plans - Components of the Net Periodic Benefit Cost of the Defined Benefit Plan (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Components of net periodic benefit cost:
Service cost
Interest cost (1)	[1]	20	18
Expected return on plan assets
Amortization of prior service cost
Amortization of net losses (1)	[1]	18	16
Net periodic benefit cost		$ 38	$ 34

[1] Bancorp elected as a practical expedient to use amounts disclosed in the 2017 consolidated financial statements as a basis for estimating quarterly application of components of defined benefit cost.