Note 4 - Financial Instruments With Off-balance-sheet Risk - Contract Amounts (Details) - USD ($)	Jun. 30, 2018	Dec. 31, 2017
Financial instruments with off-balance-sheet risk	$ 73,246,993	$ 64,567,968
Commitments to Originate and Sell Mortgage Loans [Member]
Financial instruments with off-balance-sheet risk	29,766,324	27,440,793
Commitments to Extend Credit [Member]
Financial instruments with off-balance-sheet risk	25,653,397	23,425,182
Unused lines of Credit [Member]
Financial instruments with off-balance-sheet risk	17,702,272	13,576,993
Standby Letters of Credit 1 [Member]
Financial instruments with off-balance-sheet risk	$ 125,000	$ 125,000