Note 9 - Short-term Borrowings - Short-term Borrowings (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Overnight repurchase agreements with customers	$ 7,003,122	$ 8,131,387
Federal funds purchased	6,990,000	31,840,000
	$ 13,993,122	$ 39,971,387