Note 5 - Loans and Allowance for Loan Losses - Loans by Credit Quality (Details) - USD ($)	Mar. 31, 2020	Dec. 31, 2019
Loans receivable	$ 729,798,445	$ 728,914,025
Real Estate, Construction [Member]
Loans receivable	73,114,249	77,308,551
Commercial Real Estate Portfolio Segment [Member]
Loans receivable	300,704,999	300,619,387
Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable	124,387,549	118,823,731
Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable	82,548,977	87,448,418
Commercial Portfolio Segment [Member]
Loans receivable	118,181,468	114,047,753
Consumer and Other Loans [Member]
Loans receivable	30,861,203	30,666,185
Pass [Member]
Loans receivable	696,084,000	699,557,000
Pass [Member] | Real Estate, Construction [Member]
Loans receivable	68,611,000	73,489,000
Pass [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans receivable	290,039,000	292,674,000
Pass [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable	120,947,000	115,622,000
Pass [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable	82,549,000	87,448,000
Pass [Member] | Commercial Portfolio Segment [Member]
Loans receivable	104,154,000	100,658,000
Pass [Member] | Consumer and Other Loans [Member]
Loans receivable	29,784,000	29,666,000
Special Mention [Member]
Loans receivable	11,817,000	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	2,074,000	1,476,000
Special Mention [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable	850,000	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	8,893,000	8,793,000
Special Mention [Member] | Consumer and Other Loans [Member]
Loans receivable	0	0
Substandard [Member]
Loans receivable	21,897,000	18,553,000
Substandard [Member] | Real Estate, Construction [Member]
Loans receivable	4,503,000	3,820,000
Substandard [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans receivable	8,592,000	6,469,000
Substandard [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable	2,591,000	2,667,000
Substandard [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable
Substandard [Member] | Commercial Portfolio Segment [Member]
Loans receivable	5,134,000	4,597,000
Substandard [Member] | Consumer and Other Loans [Member]
Loans receivable	1,077,000	1,000,000
Doubtful [Member]
Loans receivable
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
Doubtful [Member] | Consumer and Other Loans [Member]
Loans receivable	$ 0	$ 0