Note 4 - Loans and Allowance for Loan Losses - Loans by Aging (Details) - USD ($)	Sep. 30, 2017	Dec. 31, 2016
Loans receivable, past due	$ 4,831,000	$ 1,596,000
Loans receivable, current	619,761,000	542,802,000
Loans receivable	624,592,058	544,398,300
Loans receivable, past due and accruing
Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable, past due	2,435,000	965,000
Loans receivable, current	105,316,000	105,446,000
Loans receivable	107,750,990	106,410,559
Loans receivable, past due and accruing
Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable, past due	783,000
Loans receivable, current	73,870,000	48,483,000
Loans receivable	74,653,469	48,483,523
Loans receivable, past due and accruing
Real Estate, Construction [Member]
Loans receivable, past due
Loans receivable, current	62,047,000	40,912,000
Loans receivable	62,046,871	40,912,307
Loans receivable, past due and accruing
Commercial Real Estate Portfolio Segment [Member]
Loans receivable, past due	215,000
Loans receivable, current	266,077,000	249,581,000
Loans receivable	266,292,510	249,580,873
Loans receivable, past due and accruing
Commercial Portfolio Segment [Member]
Loans receivable, past due	1,384,000	593,000
Loans receivable, current	88,803,000	74,812,000
Loans receivable	90,186,600	75,404,732
Loans receivable, past due and accruing
Consumer and Other Loans [Member]
Loans receivable, past due	14,000	38,000
Loans receivable, current	23,648,000	23,568,000
Loans receivable	23,661,618	23,606,306
Loans receivable, past due and accruing
Financing Receivables, 30 to 59 Days Past Due [Member]
Loans receivable, past due	2,335,000	367,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable, past due	1,542,000	367,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable, past due	783,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Real Estate, Construction [Member]
Loans receivable, past due
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans receivable, past due
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member]
Loans receivable, past due
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer and Other Loans [Member]
Loans receivable, past due	10,000
Financing Receivables, 60 to 89 Days Past Due [Member]
Loans receivable, past due	648,000	495,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable, past due	644,000	495,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable, past due
Financing Receivables, 60 to 89 Days Past Due [Member] | Real Estate, Construction [Member]
Loans receivable, past due
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans receivable, past due
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member]
Loans receivable, past due
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer and Other Loans [Member]
Loans receivable, past due	4,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans receivable, past due	1,848,000	734,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable, past due	249,000	103,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable, past due
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Real Estate, Construction [Member]
Loans receivable, past due
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans receivable, past due	215,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member]
Loans receivable, past due	1,384,000	593,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer and Other Loans [Member]
Loans receivable, past due		$ 38,000