Note 4 - Loans and Allowance for Credit Losses - Loans by Risk Category (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Gross loans	$ 250,713,446	$ 238,554,157
Pass [Member]
Gross loans	83,340,683	81,726,371
Special Mention [Member]
Gross loans	40,429	335,758
Substandard [Member]
Gross loans	2,252,362	1,503,940
Doubtful [Member]
Gross loans
Not Rated [Member]
Gross loans	165,079,972	154,988,088
Residential Portfolio Segment [Member]
Gross loans	161,004,509	148,555,764
Residential Portfolio Segment [Member] | One- to Four-family Loan [Member]
Gross loans	155,143,081	141,779,340
Residential Portfolio Segment [Member] | One- to Four-family Loan [Member] | Pass [Member]
Gross loans	29,089,454	29,653,633
Residential Portfolio Segment [Member] | One- to Four-family Loan [Member] | Special Mention [Member]
Gross loans	40,429	335,758
Residential Portfolio Segment [Member] | One- to Four-family Loan [Member] | Substandard [Member]
Gross loans	1,889,452	1,048,744
Residential Portfolio Segment [Member] | One- to Four-family Loan [Member] | Doubtful [Member]
Gross loans
Residential Portfolio Segment [Member] | One- to Four-family Loan [Member] | Not Rated [Member]
Gross loans	124,123,746	110,741,205
Residential Portfolio Segment [Member] | Multi-family Loans [Member]
Gross loans	5,861,428	6,776,424
Residential Portfolio Segment [Member] | Multi-family Loans [Member] | Pass [Member]
Gross loans
Residential Portfolio Segment [Member] | Multi-family Loans [Member] | Special Mention [Member]
Gross loans
Residential Portfolio Segment [Member] | Multi-family Loans [Member] | Substandard [Member]
Gross loans
Residential Portfolio Segment [Member] | Multi-family Loans [Member] | Doubtful [Member]
Gross loans
Residential Portfolio Segment [Member] | Multi-family Loans [Member] | Not Rated [Member]
Gross loans	5,861,428	6,776,424
Nonresidential Real Estate Portfolio Segment [Member]
Gross loans	30,679,614	35,286,236
Nonresidential Real Estate Portfolio Segment [Member] | Pass [Member]
Gross loans	30,335,894	34,831,040
Nonresidential Real Estate Portfolio Segment [Member] | Special Mention [Member]
Gross loans
Nonresidential Real Estate Portfolio Segment [Member] | Substandard [Member]
Gross loans	343,720	455,196
Nonresidential Real Estate Portfolio Segment [Member] | Doubtful [Member]
Gross loans
Nonresidential Real Estate Portfolio Segment [Member] | Not Rated [Member]
Gross loans
Commercial Portfolio Segment [Member]
Gross loans	23,915,335	17,241,698
Commercial Portfolio Segment [Member] | Pass [Member]
Gross loans	23,915,335	17,241,698
Commercial Portfolio Segment [Member] | Special Mention [Member]
Gross loans
Commercial Portfolio Segment [Member] | Substandard [Member]
Gross loans
Commercial Portfolio Segment [Member] | Doubtful [Member]
Gross loans
Commercial Portfolio Segment [Member] | Not Rated [Member]
Gross loans
Consumer Portfolio Segment [Member]
Gross loans	20,562,789	15,390,263
Consumer Portfolio Segment [Member] | Pass [Member]
Gross loans
Consumer Portfolio Segment [Member] | Special Mention [Member]
Gross loans
Consumer Portfolio Segment [Member] | Substandard [Member]
Gross loans
Consumer Portfolio Segment [Member] | Doubtful [Member]
Gross loans
Consumer Portfolio Segment [Member] | Not Rated [Member]
Gross loans	20,562,789	15,390,263
Purchased Auto Loans [Member]
Gross loans	14,551,199	22,080,196
Purchased Auto Loans [Member] | Pass [Member]
Gross loans
Purchased Auto Loans [Member] | Special Mention [Member]
Gross loans
Purchased Auto Loans [Member] | Substandard [Member]
Gross loans	19,190
Purchased Auto Loans [Member] | Doubtful [Member]
Gross loans
Purchased Auto Loans [Member] | Not Rated [Member]
Gross loans	$ 14,532,009	$ 22,080,196