Note 4 - Loans and Allowance for Loan Losses - Loans by Credit Quality (Details) - USD ($)	Mar. 31, 2021	Dec. 31, 2020
Loans receivable	$ 755,152,828	$ 753,408,413
Real Estate, Construction [Member]
Loans receivable	85,711,951	70,847,330
Commercial Real Estate Portfolio Segment [Member]
Loans receivable	308,660,565	305,673,212
Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable	114,706,270	115,799,200
Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable	88,353,385	90,028,775
Commercial Portfolio Segment [Member]
Loans receivable	133,076,722	144,326,350
Consumer and Other Loans [Member]
Loans receivable	24,643,935	26,733,546
Pass [Member]
Loans receivable	686,683,000	685,352,000
Pass [Member] | Real Estate, Construction [Member]
Loans receivable	79,581,000	64,531,000
Pass [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans receivable	264,614,000	262,771,000
Pass [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable	110,881,000	110,615,000
Pass [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable	86,924,000	90,029,000
Pass [Member] | Commercial Portfolio Segment [Member]
Loans receivable	120,230,000	130,874,000
Pass [Member] | Consumer and Other Loans [Member]
Loans receivable	24,453,000	26,532,000
Special Mention [Member]
Loans receivable	11,660,000	4,565,000
Special Mention [Member] | Real Estate, Construction [Member]
Loans receivable	0	0
Special Mention [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans receivable	4,490,000	4,442,000
Special Mention [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable	729,000	0
Special Mention [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable	1,429,000	0
Special Mention [Member] | Commercial Portfolio Segment [Member]
Loans receivable	5,012,000	123,000
Special Mention [Member] | Consumer and Other Loans [Member]
Loans receivable	0	0
Substandard [Member]
Loans receivable	56,810,000	63,491,000
Substandard [Member] | Real Estate, Construction [Member]
Loans receivable	6,131,000	6,316,000
Substandard [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans receivable	39,557,000	38,460,000
Substandard [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable	3,096,000	5,184,000
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	7,835,000	13,329,000
Substandard [Member] | Consumer and Other Loans [Member]
Loans receivable	191,000	202,000
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