Note 3 - Loans and Allowance for Loan Losses - Aging of Recorded Investment in Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Past Due	$ 5,822	$ 6,194
Current	418,425	408,025
Loans	424,649	414,617
Financial Asset Acquired with Credit Deterioration [Member]
Loans	402	398
Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Past Due	4,121	4,205
Current	131,703	132,405
Loans	136,176	136,960
Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member] | Financial Asset Acquired with Credit Deterioration [Member]
Loans	352	350
Real Estate Mortgage Portfolio Segment [Member] | Land Loan [Member]
Past Due	198	281
Current	21,245	18,028
Loans	21,443	18,309
Real Estate Mortgage Portfolio Segment [Member] | Land Loan [Member] | Financial Asset Acquired with Credit Deterioration [Member]
Loans
Real Estate Mortgage Portfolio Segment [Member] | Construction Loans [Member]
Past Due
Current	21,917	21,034
Loans	21,917	21,034
Real Estate Mortgage Portfolio Segment [Member] | Construction Loans [Member] | Financial Asset Acquired with Credit Deterioration [Member]
Loans
Real Estate Mortgage Portfolio Segment [Member] | Commercial Real Estate Loan [Member]
Past Due	728	518
Current	104,198	99,774
Loans	104,976	100,340
Real Estate Mortgage Portfolio Segment [Member] | Commercial Real Estate Loan [Member] | Financial Asset Acquired with Credit Deterioration [Member]
Loans	50	48
Commercial Portfolio Segment [Member]
Past Due	268	197
Current	33,593	34,006
Loans	33,861	34,203
Commercial Portfolio Segment [Member] | Financial Asset Acquired with Credit Deterioration [Member]
Loans
Consumer Portfolio Segment [Member] | Home Equity and Second Mortgage [Member]
Past Due	126	508
Current	52,368	50,470
Loans	52,494	50,978
Consumer Portfolio Segment [Member] | Home Equity and Second Mortgage [Member] | Financial Asset Acquired with Credit Deterioration [Member]
Loans
Consumer Portfolio Segment [Member] | All Other Consumer Excluding Home Equity and Second Mortgage [Member]
Past Due	381	485
Current	53,401	52,308
Loans	53,782	52,793
Consumer Portfolio Segment [Member] | All Other Consumer Excluding Home Equity and Second Mortgage [Member] | Financial Asset Acquired with Credit Deterioration [Member]
Loans
Financing Receivables, 30 to 59 Days Past Due [Member]
Past Due	3,922	4,111
Financing Receivables, 30 to 59 Days Past Due [Member] | Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Past Due	2,468	2,612
Financing Receivables, 30 to 59 Days Past Due [Member] | Real Estate Mortgage Portfolio Segment [Member] | Land Loan [Member]
Past Due	103	186
Financing Receivables, 30 to 59 Days Past Due [Member] | Real Estate Mortgage Portfolio Segment [Member] | Construction Loans [Member]
Past Due
Financing Receivables, 30 to 59 Days Past Due [Member] | Real Estate Mortgage Portfolio Segment [Member] | Commercial Real Estate Loan [Member]
Past Due	728	379
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member]
Past Due	201	46
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Home Equity and Second Mortgage [Member]
Past Due	125	468
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member] | All Other Consumer Excluding Home Equity and Second Mortgage [Member]
Past Due	297	420
Financing Receivables, 60 to 89 Days Past Due [Member]
Past Due	609	451
Financing Receivables, 60 to 89 Days Past Due [Member] | Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Past Due	554	338
Financing Receivables, 60 to 89 Days Past Due [Member] | Real Estate Mortgage Portfolio Segment [Member] | Land Loan [Member]
Past Due
Financing Receivables, 60 to 89 Days Past Due [Member] | Real Estate Mortgage Portfolio Segment [Member] | Construction Loans [Member]
Past Due
Financing Receivables, 60 to 89 Days Past Due [Member] | Real Estate Mortgage Portfolio Segment [Member] | Commercial Real Estate Loan [Member]
Past Due
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member]
Past Due		49
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Home Equity and Second Mortgage [Member]
Past Due	1	27
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member] | All Other Consumer Excluding Home Equity and Second Mortgage [Member]
Past Due	54	37
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past Due	1,291	1,632
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Past Due	1,099	1,255
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Real Estate Mortgage Portfolio Segment [Member] | Land Loan [Member]
Past Due	95	95
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Real Estate Mortgage Portfolio Segment [Member] | Construction Loans [Member]
Past Due
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Real Estate Mortgage Portfolio Segment [Member] | Commercial Real Estate Loan [Member]
Past Due		139
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member]
Past Due	67	102
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Home Equity and Second Mortgage [Member]
Past Due		13
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Portfolio Segment [Member] | All Other Consumer Excluding Home Equity and Second Mortgage [Member]
Past Due	$ 30	$ 28