Note 3 - Loans Receivable - Past Due and Non-accrual Status of Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Loans, past due	$ 1,616	$ 4,141
Loans, current	459,836	440,054
Loans	461,452	444,195
Loans, nonaccrual loans	1,639	1,144
Construction Loan Portfolio Segment [Member] | Residential [Member]
Loans, past due	839
Loans, current	19,304	15,221
Loans	20,143	15,221
Loans, nonaccrual loans
Construction Loan Portfolio Segment [Member] | Land Acquisition Development And Commercial [Member]
Loans, past due		317
Loans, current	21,343	35,284
Loans	21,343	35,601
Loans, nonaccrual loans	308	274
Real Estate Portfolio Segment [Member] | Residential [Member]
Loans, past due	99	2,005
Loans, current	134,622	119,644
Loans	134,721	121,649
Loans, nonaccrual loans	460	173
Real Estate Portfolio Segment [Member] | Commercial [Member]
Loans, past due	460	506
Loans, current	188,217	173,493
Loans	188,677	173,999
Loans, nonaccrual loans	471	209
Commercial Industrial and Agricultural Portfolio Segment [Member]
Loans, past due	13	665
Loans, current	59,578	60,532
Loans	59,591	61,197
Loans, nonaccrual loans	278	403
Equity Lines Portfolio Segment [Member]
Loans, past due	193	593
Loans, current	29,101	28,242
Loans	29,294	28,835
Loans, nonaccrual loans	122	49
Consumer Portfolio Segment [Member]
Loans, past due	12	55
Loans, current	7,671	7,638
Loans	7,683	7,693
Loans, nonaccrual loans		36
Financing Receivables, 30 to 59 Days Past Due [Member]
Loans, past due	1,516	1,601
Financing Receivables, 30 to 59 Days Past Due [Member] | Construction Loan Portfolio Segment [Member] | Residential [Member]
Loans, past due	839
Financing Receivables, 30 to 59 Days Past Due [Member] | Construction Loan Portfolio Segment [Member] | Land Acquisition Development And Commercial [Member]
Loans, past due		43
Financing Receivables, 30 to 59 Days Past Due [Member] | Real Estate Portfolio Segment [Member] | Residential [Member]
Loans, past due	99	589
Financing Receivables, 30 to 59 Days Past Due [Member] | Real Estate Portfolio Segment [Member] | Commercial [Member]
Loans, past due	460	278
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Industrial and Agricultural Portfolio Segment [Member]
Loans, past due	13	130
Financing Receivables, 30 to 59 Days Past Due [Member] | Equity Lines Portfolio Segment [Member]
Loans, past due	93	544
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member]
Loans, past due	12	17
Financing Receivables, 60 to 89 Days Past Due [Member]
Loans, past due	100	1,083
Financing Receivables, 60 to 89 Days Past Due [Member] | Construction Loan Portfolio Segment [Member] | Residential [Member]
Loans, past due
Financing Receivables, 60 to 89 Days Past Due [Member] | Construction Loan Portfolio Segment [Member] | Land Acquisition Development And Commercial [Member]
Loans, past due
Financing Receivables, 60 to 89 Days Past Due [Member] | Real Estate Portfolio Segment [Member] | Residential [Member]
Loans, past due		870
Financing Receivables, 60 to 89 Days Past Due [Member] | Real Estate Portfolio Segment [Member] | Commercial [Member]
Loans, past due		19
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Industrial and Agricultural Portfolio Segment [Member]
Loans, past due		143
Financing Receivables, 60 to 89 Days Past Due [Member] | Equity Lines Portfolio Segment [Member]
Loans, past due	100	49
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member]
Loans, past due		2
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans, past due		1,457
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Construction Loan Portfolio Segment [Member] | Residential [Member]
Loans, past due
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Construction Loan Portfolio Segment [Member] | Land Acquisition Development And Commercial [Member]
Loans, past due		274
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Real Estate Portfolio Segment [Member] | Residential [Member]
Loans, past due		546
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Real Estate Portfolio Segment [Member] | Commercial [Member]
Loans, past due		209
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Industrial and Agricultural Portfolio Segment [Member]
Loans, past due		392
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Equity Lines Portfolio Segment [Member]
Loans, past due
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Portfolio Segment [Member]
Loans, past due		$ 36