Note 5 - Loans and Allowance for Loan Losses - Loans by Credit Quality (Details) - USD ($)	Sep. 30, 2020	Dec. 31, 2019
Loans receivable	$ 783,278,283	$ 728,914,025
Real Estate, Construction [Member]
Loans receivable	69,915,937	77,308,551
Commercial Real Estate Portfolio Segment [Member]
Loans receivable	304,555,366	300,619,387
Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable	128,467,837	118,823,731
Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable	89,762,581	87,448,418
Commercial Portfolio Segment [Member]
Loans receivable	163,097,935	114,047,753
Consumer and Other Loans [Member]
Loans receivable	27,478,627	30,666,185
Pass [Member]
Loans receivable	745,238,000	699,557,000
Pass [Member] | Real Estate, Construction [Member]
Loans receivable	62,798,000	73,489,000
Pass [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans receivable	293,510,000	292,674,000
Pass [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable	122,995,000	115,622,000
Pass [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable	89,763,000	87,448,000
Pass [Member] | Commercial Portfolio Segment [Member]
Loans receivable	148,922,000	100,658,000
Pass [Member] | Consumer and Other Loans [Member]
Loans receivable	27,251,000	29,666,000
Special Mention [Member]
Loans receivable	6,904,000	10,804,000
Special Mention [Member] | Real Estate, Construction [Member]
Loans receivable	0	0
Special Mention [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans receivable	620,000	1,476,000
Special Mention [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable	1,023,000	535,000
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	5,261,000	8,793,000
Special Mention [Member] | Consumer and Other Loans [Member]
Loans receivable	0	0
Substandard [Member]
Loans receivable	31,136,000	18,553,000
Substandard [Member] | Real Estate, Construction [Member]
Loans receivable	7,118,000	3,820,000
Substandard [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans receivable	10,425,000	6,469,000
Substandard [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable	4,450,000	2,667,000
Substandard [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable	0	0
Substandard [Member] | Commercial Portfolio Segment [Member]
Loans receivable	8,915,000	4,597,000
Substandard [Member] | Consumer and Other Loans [Member]
Loans receivable	228,000	1,000,000
Doubtful [Member]
Loans receivable	0	0
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	0
Doubtful [Member] | Consumer and Other Loans [Member]
Loans receivable	$ 0	$ 0