Note 4 - Loans - TDRs With Subsequent Default (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)
Number of TDR defaults	0	0	1	4
Recorded investment TDR defaults			$ 10	$ 825
Residential Portfolio Segment [Member]
Number of TDR defaults			0	3
Recorded investment TDR defaults			$ 0	$ 145
Commercial Real Estate Portfolio Segment [Member]
Number of TDR defaults		1	0	1
Recorded investment TDR defaults			$ 0	$ 680
Construction, Land Acquisition and Development [Member]
Number of TDR defaults			1	0
Recorded investment TDR defaults			$ 10	$ 0
Commercial and Industrial [Member]
Number of TDR defaults			0	0
Recorded investment TDR defaults			$ 0	$ 0
Consumer Portfolio Segment [Member]
Number of TDR defaults			0	0
Recorded investment TDR defaults			$ 0	$ 0
State and Political Subdivisions [Member]
Number of TDR defaults			0	0
Recorded investment TDR defaults			$ 0	$ 0