Note 3 - Investment Securities - Contractual Maturities (Details) - USD ($)	Mar. 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	804,270	1,009,284
Held to Maturity Fair value, Within one year	805,908	1,011,165
Available for Sale Amortized cost, Over one to five years	259,981	260,587
Available for Sale Fair value,Over one to five years	254,753	249,920
Held to Maturity Amortized cost, Over one to five years	589,690	590,522
Held to Maturity Fair value, Over one to five years	597,571	598,528
Available for Sale Amortized cost, Over five to ten years	870,302	870,424
Available for Sale Fair value, Over five to ten years	878,537	880,932
Held to Maturity Amortized cost, Over five to ten years	1,859,628	1,858,695
Held to Maturity Fair value, Over five to ten years	1,900,827	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	14,812,405	14,668,566
Held to Maturity Fair value, Over ten years	14,931,879	14,547,036
Available for Sale Amortized cost, total maturity	1,130,283	1,506,011
Available for Sale Fair value, total maturity	1,133,290	1,506,505
Held to Maturity Amortized cost, total maturity	18,065,993	18,127,067
Held to Maturity Fair value, total maturity	18,236,185	18,033,093
Available for Sale Amortized cost, due in monthly installments	29,843,231	25,870,029
Available for Sale Fair value, due in monthly installments	29,468,481	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	30,973,514	27,376,040
Available for Sale Fair value Total	30,601,771	26,591,991
Held to Maturity Amortized cost Total	18,065,993	18,127,067
Held to Maturity Fair value Total	$ 18,236,185	$ 18,033,093