Note 1 - Summary of Significant Accounting Policies (Details Textual) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2018	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Period Look-back, Quarters				28	24
Allowance for Loan and Lease Losses, Period Increase (Decrease)		$ 474
Goodwill, Impairment Loss				$ 0
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent				35.00%	35.00%	35.00%
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability	$ 5,900
Unrecognized Tax Benefits	$ 40			$ 40	$ 40	$ 40
Aggregate Number of Full Service Branche Locations	37			37
Number of Operating Segments				2
Fair Value Hedging [Member]
Derivative, Number of Instruments Held	0			0	0
Scenario, Forecast [Member]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent			21.00%
Minimum [Member]
Property, Plant and Equipment, Useful Life				3 years
Maximum [Member]
Property, Plant and Equipment, Useful Life				40 years