Note 8 - Time Deposits (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Time Deposits, at or Above FDIC Insurance Limit	$ 12,500,000	$ 11,800,000
Time Deposits, 250,000 or More, Mature With in One Year	10,300,000	6,700,000
Interest Expense, Time Deposits, 250,000 or More	$ 80,000	$ 74,000