Note 5 - Loans - Average Balance and Interest Income by Loan Category Recognized on Impaired Loans (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018
Average Balance		$ 13,778	$ 11,637
Interest Income	[1]	398	417
Residential Portfolio Segment [Member] | Real Estate Loan [Member]
Average Balance		2,157	1,827
Interest Income	[1]	84	83
Commercial Real Estate Portfolio Segment [Member] | Real Estate Loan [Member]
Average Balance		10,092	8,580
Interest Income	[1]	297	311
Construction, Land Acquisition and Development [Member] | Real Estate Loan [Member]
Average Balance		79	83
Interest Income	[1]	5	5
Commercial and Industrial [Member]
Average Balance		1,207	759
Interest Income	[1]	1	1
Consumer Portfolio Segment [Member]
Average Balance		243	388
Interest Income	[1]	11	17
State and Political Subdivisions [Member]
Average Balance		0	0
Interest Income	[1]	$ 0	$ 0

[1] Interest income represents income recognized on performing TDRs.