Note 8 - Loans and Allowance for Credit Losses - Aging of the Recorded Investment in Loans (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Loans past due	$ 3,262,127	$ 4,361,693
Loans, current	235,159,495	234,192,464
Total loans	238,421,622	238,554,157
Financial Asset, 30 to 59 Days Past Due [Member]
Loans past due	2,605,543	2,751,238
Financial Asset, 60 to 89 Days Past Due [Member]
Loans past due	286,492	694,864
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans past due	370,092	915,591
Residential Portfolio Segment [Member]
Total loans	151,855,869	148,555,764
Residential Portfolio Segment [Member] | One- to Four-family Loan [Member]
Loans past due	2,638,715	2,630,600
Loans, current	142,541,428	139,148,740
Total loans	145,180,143	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	2,290,101	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	107,858	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	240,756	788,127
Residential Portfolio Segment [Member] | Multi-family Loans [Member]
Loans past due	0	0
Loans, current	6,675,726	6,776,424
Total loans	6,675,726	6,776,424
Residential Portfolio Segment [Member] | Multi-family Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Loans past due	0	0
Residential Portfolio Segment [Member] | Multi-family Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Loans past due	0	0
Residential Portfolio Segment [Member] | Multi-family Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans past due	0	0
Nonresidential Real Estate Portfolio Segment [Member]
Loans past due	432,189	1,670,320
Loans, current	31,007,819	33,615,916
Total loans	31,440,008	35,286,236
Nonresidential Real Estate Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Loans past due	302,853	1,413,392
Nonresidential Real Estate Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Loans past due		129,464
Nonresidential Real Estate Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans past due	129,336	127,464
Commercial Portfolio Segment [Member]
Loans past due	189,138	3,989
Loans, current	18,021,656	17,237,709
Total loans	18,210,794	17,241,698
Commercial Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Loans past due	10,504	3,989
Commercial Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Loans past due	178,634
Commercial Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans past due		0
Consumer Portfolio Segment [Member]
Loans past due		9,044
Loans, current	16,708,018	15,381,219
Total loans	16,708,018	15,390,263
Consumer Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Loans past due		9,044
Consumer Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Loans past due	0	0
Consumer Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans past due	0	0
Purchased Auto Loans [Member]
Loans past due	2,085	47,740
Loans, current	20,204,848	22,032,456
Total loans	20,206,933	22,080,196
Purchased Auto Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Loans past due	2,085	31,671
Purchased Auto Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Loans past due		16,069
Purchased Auto Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans past due