Note 4 - Financial Instruments With Off-balance-sheet Risk - Contract Amounts (Details) - USD ($)	Mar. 31, 2018	Dec. 31, 2017
Financial instruments with off-balance-sheet risk	$ 84,134,592	$ 64,567,968
Commitments to Originate and Sell Mortgage Loans [Member]
Financial instruments with off-balance-sheet risk	37,833,362	27,440,793
Commitments to Extend Credit [Member]
Financial instruments with off-balance-sheet risk	32,356,902	23,425,182
Unused lines of Credit [Member]
Financial instruments with off-balance-sheet risk	13,819,328	13,576,993
Standby Letters of Credit 1 [Member]
Financial instruments with off-balance-sheet risk	$ 125,000	$ 125,000