Note 7 - Other Borrowed Funds - Federal Home Loan Bank Advances (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Due in One Year, amount	$ 3.5
Due in One Year, weighted average rate	1.35%
Due After One Year to Two Years, amount	$ 4.0	$ 3.5
Due After One Year to Two Years, weighted average rate	1.67%	0.94%
Due After Two Years to Three Years, amount	$ 6.0	$ 4.5
Due After Two Years to Three Years, weighted average rate	1.88%	1.41%
Due After Three Years to Four Years, amount	$ 5.0	$ 6.0
Due After Three Years to Four Years, weighted average rate	2.09%	1.78%
Due After Four Years to Five Years, amount	$ 3.0	$ 6.0
Due After Four Years to Five Years, weighted average rate	2.23%	1.97%
Due After Five Years, amount	$ 3.0	$ 8.0
Due After Five Years, weighted average rate	2.41%	2.27%
Total, amount	$ 24.5	$ 28.0
Weighted Average [Member]
Total, weighted average rate	1.92%	1.80%