Note 4 - Loans and Allowance for Loan Losses - Loans by Credit Quality (Details) - USD ($)	Mar. 31, 2018	Dec. 31, 2017
Loans receivable	$ 645,706,047	$ 637,375,018
Real Estate, Construction [Member]
Loans receivable	81,228,819	64,743,582
Commercial Real Estate Portfolio Segment [Member]
Loans receivable	254,715,822	261,866,285
Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable	105,840,035	106,300,790
Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable	81,982,799	85,225,074
Commercial Portfolio Segment [Member]
Loans receivable	97,830,737	94,522,840
Consumer and Other Loans [Member]
Loans receivable	24,107,835	24,716,447
Pass [Member]
Loans receivable	619,792,000	613,664,000
Pass [Member] | Real Estate, Construction [Member]
Loans receivable	76,778,000	60,291,000
Pass [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans receivable	244,309,000	254,658,000
Pass [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable	97,103,000	96,723,000
Pass [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable	81,220,000	84,450,000
Pass [Member] | Commercial Portfolio Segment [Member]
Loans receivable	96,355,000	93,102,000
Pass [Member] | Consumer and Other Loans [Member]
Loans receivable	24,027,000	24,440,000
Special Mention [Member]
Loans receivable	10,002,000	9,577,000
Special Mention [Member] | Real Estate, Construction [Member]
Loans receivable	0	0
Special Mention [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans receivable	6,573,000	5,578,000
Special Mention [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable	3,133,000	3,799,000
Special Mention [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable	0	0
Special Mention [Member] | Commercial Portfolio Segment [Member]
Loans receivable	296,000	200,000
Special Mention [Member] | Consumer and Other Loans [Member]
Loans receivable	0	0
Substandard [Member]
Loans receivable	15,912,000	13,621,000
Substandard [Member] | Real Estate, Construction [Member]
Loans receivable	4,451,000	4,453,000
Substandard [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans receivable	3,834,000	1,630,000
Substandard [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable	5,604,000	5,779,000
Substandard [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable	763,000	775,000
Substandard [Member] | Commercial Portfolio Segment [Member]
Loans receivable	1,179,000	708,000
Substandard [Member] | Consumer and Other Loans [Member]
Loans receivable	81,000	276,000
Doubtful [Member]
Loans receivable	0	513,000
Doubtful [Member] | Real Estate, Construction [Member]
Loans receivable	0	0
Doubtful [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans receivable	0	0
Doubtful [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable	0	0
Doubtful [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable	0	0
Doubtful [Member] | Commercial Portfolio Segment [Member]
Loans receivable	0	513,000
Doubtful [Member] | Consumer and Other Loans [Member]
Loans receivable	$ 0	$ 0