Note 8 - Time Deposits - Time Deposit Maturities (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Weighted average rate, one year or less	1.06%	0.84%
One year or less, amount	$ 31,916,859	$ 39,693,113
Weighted average rate, over one through three years	1.28%	0.93%
Over one through three years, amount	$ 27,678,266	$ 18,866,903
Weighted average rate, over three through five years	1.26%	1.17%
Over three through five years, amount	$ 3,454,209	$ 5,000,566
Weighted average rate, over five years	0.00%	0.00%
Over five years, amount	$ 0	$ 0
Weighted average rate	1.17%	0.90%
Amount	$ 63,049,334	$ 63,560,582