Note 3 - Investment Securities - Contractual Maturities (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Available for Sale Amortized cost, Within one year		$ 375,000
Available for Sale Fair value, Within one year		375,653
Held to Maturity Amortized cost, Within one year	257,150	1,009,284
Held to Maturity Fair value, Within one year	261,204	1,011,165
Available for Sale Amortized cost, Over one to five years	258,134	260,587
Available for Sale Fair value, Over one to five years	258,838	249,920
Held to Maturity Amortized cost, Over one to five years	562,587	590,522
Held to Maturity Fair value, Over one to five years	565,140	598,528
Available for Sale Amortized cost, Over five to ten years	250,000	870,424
Available for Sale Fair value, Over five to ten years	253,832	880,932
Held to Maturity Amortized cost, Over five to ten years	2,717,125	1,858,695
Held to Maturity Fair value, Over five to ten years	2,782,474	1,876,364
Available for Sale Amortized cost, Over ten years
Available for Sale Fair value, Over ten years
Held to Maturity Amortized cost, Over ten years	15,973,156	14,668,566
Held to Maturity Fair value, Over ten years	16,489,113	14,547,036
Available for Sale Amortized cost, total maturity	508,134	1,506,011
Available for Sale Fair value, total maturity	512,670	1,506,505
Held to Maturity Amortized cost, total maturity	19,510,018	18,127,067
Held to Maturity Fair value, total maturity	20,097,931	18,033,093
Available for Sale Amortized cost, due in monthly installments	35,964,833	25,870,029
Available for Sale Fair value, due in monthly installments	36,019,104	25,085,486
Held to Maturity Amortized cost, due in monthly installments
Held to Maturity Fair value, due in monthly installments
Available for Sale Amortized cost Total	36,472,967	27,376,040
Available for Sale Fair value Total	36,531,774	26,591,991
Held to Maturity Amortized cost Total	19,510,018	18,127,067
Held to Maturity Fair value Total	$ 20,097,931	$ 18,033,093