Note 4 - Loans - Average Balance and Interest Income by Loan Category Recognized on Impaired Loans (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
Average Balance		$ 15,172	$ 12,978
Interest Income	[1]	91	104
Residential Portfolio Segment [Member] | Real Estate Loan [Member]
Average Balance		2,569	1,839
Interest Income	[1]	20	21
Commercial Real Estate Portfolio Segment [Member] | Real Estate Loan [Member]
Average Balance		11,321	9,630
Interest Income	[1]	68	77
Construction, Land Acquisition and Development [Member] | Real Estate Loan [Member]
Average Balance		75	82
Interest Income	[1]	1	1
Commercial and Industrial [Member]
Average Balance		1,014	1,047
Interest Income	[1]
Consumer Portfolio Segment [Member]
Average Balance		193	380
Interest Income	[1]	2	5
State and Political Subdivisions [Member]
Average Balance
Interest Income	[1]

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