Note 12 - Defined Benefit Plan - Components of the Net Periodic Benefit Cost of the Defined Benefit Plan (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Interest cost (1)	[1]	$ 19	$ 18	$ 59	$ 54
Service cost
Expected return on plan assets
Amortization of prior service cost
Amortization of net losses (1)	[1]	18	16	54	49
Net periodic benefit cost		$ 37	$ 34	$ 113	$ 103

[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.