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 |