Note 4 - Financial Instruments With Off-balance-sheet Risk - Contract Amounts (Details) - USD ($)	Sep. 30, 2017	Dec. 31, 2016
Fair Value Disclosures, Off-balance Sheet Risks, Amount	$ 73,376,592	$ 63,300,253
Financial Standby Letter of Credit [Member]
Fair Value Disclosures, Off-balance Sheet Risks, Amount	125,000
Commitments to Originate and Sell Mortgage Loans [Member]
Fair Value Disclosures, Off-balance Sheet Risks, Amount	27,343,176	27,206,868
Commitments to Extend Credit [Member]
Fair Value Disclosures, Off-balance Sheet Risks, Amount	34,312,331	27,430,757
Unused lines of Credit [Member]
Fair Value Disclosures, Off-balance Sheet Risks, Amount	$ 11,596,085	$ 8,662,628