Note 3 - Loans and Allowance for Loan Losses - Recorded Investment in Loans by Risk Category (Details) - USD ($)	Sep. 30, 2017	Dec. 31, 2016
Loans	$ 405,561,000	$ 385,764,000
Pass [Member]
Loans	394,616	372,497,000
Special Mention [Member]
Loans	4,200,000	3,087,000
Substandard [Member]
Loans	4,034,000	6,863,000
Doubtful [Member]
Loans	2,711,000	3,317,000
Unlikely to be Collected Financing Receivable [Member]
Loans	0	0
Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Loans	136,813,000	138,377,000
Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member] | Pass [Member]
Loans	133,323	135,328,000
Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member] | Special Mention [Member]
Loans	385,000	403,000
Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member] | Substandard [Member]
Loans	721,000	721,000
Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member] | Doubtful [Member]
Loans	2,384,000	1,925,000
Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member] | Unlikely to be Collected Financing Receivable [Member]
Loans	0	0
Real Estate Mortgage Portfolio Segment [Member] | Land Loan [Member]
Loans	17,737,000	13,951,000
Real Estate Mortgage Portfolio Segment [Member] | Land Loan [Member] | Pass [Member]
Loans	17,528	13,795,000
Real Estate Mortgage Portfolio Segment [Member] | Land Loan [Member] | Special Mention [Member]
Loans	85,000	86,000
Real Estate Mortgage Portfolio Segment [Member] | Land Loan [Member] | Substandard [Member]
Loans	124,000	70,000
Real Estate Mortgage Portfolio Segment [Member] | Land Loan [Member] | Doubtful [Member]
Loans	0	0
Real Estate Mortgage Portfolio Segment [Member] | Land Loan [Member] | Unlikely to be Collected Financing Receivable [Member]
Loans	0	0
Real Estate Mortgage Portfolio Segment [Member] | Construction Loans [Member]
Loans	23,019,000	19,489,000
Real Estate Mortgage Portfolio Segment [Member] | Construction Loans [Member] | Pass [Member]
Loans	22,952	19,489,000
Real Estate Mortgage Portfolio Segment [Member] | Construction Loans [Member] | Special Mention [Member]
Loans	67,000	0
Real Estate Mortgage Portfolio Segment [Member] | Construction Loans [Member] | Substandard [Member]
Loans	0	0
Real Estate Mortgage Portfolio Segment [Member] | Construction Loans [Member] | Doubtful [Member]
Loans	0	0
Real Estate Mortgage Portfolio Segment [Member] | Construction Loans [Member] | Unlikely to be Collected Financing Receivable [Member]
Loans	0	0
Real Estate Mortgage Portfolio Segment [Member] | Commercial Real Estate Loan [Member]
Loans	95,512,000	96,669,000
Real Estate Mortgage Portfolio Segment [Member] | Commercial Real Estate Loan [Member] | Pass [Member]
Loans	89,685	87,782,000
Real Estate Mortgage Portfolio Segment [Member] | Commercial Real Estate Loan [Member] | Special Mention [Member]
Loans	2,749,000	1,892,000
Real Estate Mortgage Portfolio Segment [Member] | Commercial Real Estate Loan [Member] | Substandard [Member]
Loans	3,045,000	5,991,000
Real Estate Mortgage Portfolio Segment [Member] | Commercial Real Estate Loan [Member] | Doubtful [Member]
Loans	33,000	1,004,000
Real Estate Mortgage Portfolio Segment [Member] | Commercial Real Estate Loan [Member] | Unlikely to be Collected Financing Receivable [Member]
Loans	0	0
Commercial Portfolio Segment [Member]
Loans	28,598,000	24,126,000
Commercial Portfolio Segment [Member] | Pass [Member]
Loans	27,620	23,246,000
Commercial Portfolio Segment [Member] | Special Mention [Member]
Loans	781,000	661,000
Commercial Portfolio Segment [Member] | Substandard [Member]
Loans	142,000	77,000
Commercial Portfolio Segment [Member] | Doubtful [Member]
Loans	55,000	142,000
Commercial Portfolio Segment [Member] | Unlikely to be Collected Financing Receivable [Member]
Loans	0	0
Consumer Portfolio Segment [Member] | Home Equity and Second Mortgage [Member]
Loans	50,079,000	43,831,000
Consumer Portfolio Segment [Member] | Home Equity and Second Mortgage [Member] | Pass [Member]
Loans	49,838	43,601,000
Consumer Portfolio Segment [Member] | Home Equity and Second Mortgage [Member] | Special Mention [Member]
Loans	0	0
Consumer Portfolio Segment [Member] | Home Equity and Second Mortgage [Member] | Substandard [Member]
Loans	2,000	4,000
Consumer Portfolio Segment [Member] | Home Equity and Second Mortgage [Member] | Doubtful [Member]
Loans	239,000	226,000
Consumer Portfolio Segment [Member] | Home Equity and Second Mortgage [Member] | Unlikely to be Collected Financing Receivable [Member]
Loans	0	0
Consumer Portfolio Segment [Member] | Other Consumer Loan [Member]
Loans	53,803,000	49,321,000
Consumer Portfolio Segment [Member] | Other Consumer Loan [Member] | Pass [Member]
Loans	53,670	49,256,000
Consumer Portfolio Segment [Member] | Other Consumer Loan [Member] | Special Mention [Member]
Loans	133,000	45,000
Consumer Portfolio Segment [Member] | Other Consumer Loan [Member] | Substandard [Member]
Loans	0	0
Consumer Portfolio Segment [Member] | Other Consumer Loan [Member] | Doubtful [Member]
Loans	0	20,000
Consumer Portfolio Segment [Member] | Other Consumer Loan [Member] | Unlikely to be Collected Financing Receivable [Member]
Loans	$ 0	$ 0