Note 2 - Securities - Available-for-sale Securities by Maturity (Details) - USD ($)	Dec. 31, 2021	Dec. 31, 2020
1-5 years, amortized cost	$ 1,500,000
1-5 years, fair value	1,497,325
6-10 years, amortized cost	37,399,244
6-10 years, fair value	37,449,981
After 10 years, amortized cost	51,881,188
After 10 years, fair value	52,360,444
Not due on a single maturity date, amortized cost	150,885,212	$ 159,249,817
Available-for-sale securities	151,402,498	164,120,869
Commercial Mortgage Backed Securities [Member]
Not due on a single maturity date, amortized cost	7,384,249
Not due on a single maturity date, fair value	7,368,422
Not due on a single maturity date, amortized cost	7,384,249
Not due on a single maturity date, amortized cost	7,384,249
Available-for-sale securities	7,368,422
Residential Mortgage Backed Securities [Member]
Not due on a single maturity date, amortized cost	9,057,185
Not due on a single maturity date, fair value	9,053,592
Not due on a single maturity date, amortized cost	9,057,185
Not due on a single maturity date, amortized cost	9,057,185	9,249,375
Available-for-sale securities	9,053,592	9,452,097
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Not due on a single maturity date, amortized cost	43,663,346
Not due on a single maturity date, fair value	43,672,734
Not due on a single maturity date, amortized cost	43,663,346
Not due on a single maturity date, amortized cost	43,663,346	49,053,252
Available-for-sale securities	$ 43,672,734	$ 50,370,815