Note 8 - Borrowings - Federal Home Loan Bank Advances (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Amount	$ 94,300,000	$ 95,700,000
Weighted average rate	1.97%	1.72%
Federal Home Loan Bank Advances Maturing in 2018 [Member]
Amount	$ 92,200,000	$ 43,600,000
Weighted average rate	1.90%	0.79%
Federal Home Loan Bank Advances Maturing in 2019 [Member]
Amount	$ 2,100,000	$ 50,000,000
Weighted average rate	4.87%	2.14%
Federal Home Loan Bank Advances Maturing in 2020 [Member]
Amount		$ 2,100,000
Weighted average rate	0.00%	4.87%