Note 7 - Deposits - Interest Expense on Deposits (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
NOW and Money Market accounts	$ 2,394,549	$ 1,235,359	$ 1,276,808
Savings accounts	58,384	55,094	49,467
Certificate accounts	1,309,629	1,002,872	1,102,928
Early withdrawal penalties	(10,997)	(9,343)	(5,332)
	$ 3,751,565	$ 2,283,982	$ 2,423,871