Note 4 - Loans - Average Balance and Interest Income by Loan Category Recognized on Impaired Loans (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018		Jun. 30, 2017
Average Balance		$ 10,898	$ 10,734	$ 10,939	[1]	$ 9,315	[1]
Interest Income	[1]	101	106	204		176
Residential Portfolio Segment [Member] | Real Estate Loan [Member]
Average Balance		1,805	1,841	1,837	[1]	1,884	[1]
Interest Income	[1]	21	21	42		42
Commercial Real Estate Portfolio Segment [Member] | Real Estate Loan [Member]
Average Balance		7,826	7,452	7,833	[1]	6,133	[1]
Interest Income	[1]	75	72	152		112
Construction, Land Acquisition and Development [Member] | Real Estate Loan [Member]
Average Balance		84	87	84	[1]	123	[1]
Interest Income	[1]	1	1	2		2
Commercial and Industrial [Member]
Average Balance		794	1,059	794	[1]	879	[1]
Interest Income	[1]	1	9	1		14
Consumer Portfolio Segment [Member]
Average Balance		389	295	391	[1]	296	[1]
Interest Income	[1]	3	3	7		6
State and Political Subdivisions [Member]
Average Balance		0	0		[1]		[1]
Interest Income	[1]	$ 0	$ 0

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