Note 4 - Loans and Allowance for Loan Losses - Loans by Credit Quality (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Loans receivable	$ 786,894,894	$ 637,375,018
Real Estate, Construction [Member]
Loans receivable	88,553,995	64,743,582
Commercial Real Estate Portfolio Segment [Member]
Loans receivable	322,921,323	261,866,285
Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable	132,410,810	106,300,790
Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable	90,548,265	85,225,074
Commercial Portfolio Segment [Member]
Loans receivable	119,369,484	94,522,840
Consumer and Other Loans [Member]
Loans receivable	33,091,017	24,716,447
Pass [Member]
Loans receivable	753,254,000	613,664,000
Pass [Member] | Real Estate, Construction [Member]
Loans receivable	84,375,000	60,291,000
Pass [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans receivable	310,486,000	254,658,000
Pass [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable	126,586,000	96,723,000
Pass [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable	84,596,000	84,450,000
Pass [Member] | Commercial Portfolio Segment [Member]
Loans receivable	114,525,000	93,102,000
Pass [Member] | Consumer and Other Loans [Member]
Loans receivable	32,686,000	24,440,000
Special Mention [Member]
Loans receivable	8,927,000	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	5,524,000	5,578,000
Special Mention [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable	372,000	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	3,031,000	200,000
Special Mention [Member] | Consumer and Other Loans [Member]
Loans receivable	0	0
Substandard [Member]
Loans receivable	24,714,000	13,621,000
Substandard [Member] | Real Estate, Construction [Member]
Loans receivable	4,179,000	4,453,000
Substandard [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans receivable	6,911,000	1,630,000
Substandard [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable	5,453,000	5,779,000
Substandard [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable	5,952,000	775,000
Substandard [Member] | Commercial Portfolio Segment [Member]
Loans receivable	1,814,000	708,000
Substandard [Member] | Consumer and Other Loans [Member]
Loans receivable	405,000	276,000
Doubtful [Member]
Loans receivable		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		513,000
Doubtful [Member] | Consumer and Other Loans [Member]
Loans receivable	$ 0	$ 0