Note 4 - Loans and Allowance for Credit Losses - Aging of the Recorded Investment in Loans (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Loans past due	$ 5,225,158	$ 4,361,693
Loans, current	245,488,288	234,192,464
Total loans	250,713,446	238,554,157
Financial Asset, 30 to 59 Days Past Due [Member]
Loans past due	3,474,498	2,751,238
Financial Asset, 60 to 89 Days Past Due [Member]
Loans past due	745,441	694,864
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans past due	1,005,219	915,591
Residential Portfolio Segment [Member]
Total loans	161,004,509	148,555,764
Residential Portfolio Segment [Member] | One- to Four-family Loan [Member]
Loans past due	4,228,516	2,630,600
Loans, current	150,914,565	139,148,740
Total loans	155,143,081	141,779,340
Residential Portfolio Segment [Member] | One- to Four-family Loan [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Loans past due	2,635,464	1,293,142
Residential Portfolio Segment [Member] | One- to Four-family Loan [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Loans past due	607,023	549,331
Residential Portfolio Segment [Member] | One- to Four-family Loan [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans past due	986,029	788,127
Residential Portfolio Segment [Member] | Multi-family Loans [Member]
Loans past due	104,716
Loans, current	5,756,712	6,776,424
Total loans	5,861,428	6,776,424
Residential Portfolio Segment [Member] | Multi-family Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Loans past due	104,716
Residential Portfolio Segment [Member] | Multi-family Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Loans past due
Residential Portfolio Segment [Member] | Multi-family Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans past due
Nonresidential Real Estate Portfolio Segment [Member]
Loans past due	336,254	1,670,320
Loans, current	30,343,360	33,615,916
Total loans	30,679,614	35,286,236
Nonresidential Real Estate Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Loans past due	272,138	1,413,392
Nonresidential Real Estate Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Loans past due	64,116	129,464
Nonresidential Real Estate Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans past due		127,464
Commercial Portfolio Segment [Member]
Loans past due	421,077	3,989
Loans, current	23,494,258	17,237,709
Total loans	23,915,335	17,241,698
Commercial Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Loans past due	368,448	3,989
Commercial Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Loans past due	52,629
Commercial Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans past due
Consumer Portfolio Segment [Member]
Loans past due	29,243	9,044
Loans, current	20,533,546	15,381,219
Total loans	20,562,789	15,390,263
Consumer Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Loans past due	29,243	9,044
Consumer Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Loans past due
Consumer Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans past due
Purchased Auto Loans [Member]
Loans past due	105,352	47,740
Loans, current	14,445,847	22,032,456
Total loans	14,551,199	22,080,196
Purchased Auto Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Loans past due	64,489	31,671
Purchased Auto Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Loans past due	21,673	16,069
Purchased Auto Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans past due	$ 19,190