Note 4 - Securities - Fair Market Value of Securities Segregated by Purpose (Details) $ in Thousands	Dec. 31, 2016 USD ($)
Pledged Securities	$ 39,215
Federal Home Loan Bank Borrowings [Member]
Pledged Securities	15,080
Public Funds Collateral [Member]
Pledged Securities	24,135
Securities Pledged as Collateral [Member]
Pledged Securities	17,281
Securities Pledged as Collateral [Member] | Federal Home Loan Bank Borrowings [Member]
Pledged Securities
Securities Pledged as Collateral [Member] | Public Funds Collateral [Member]
Pledged Securities	17,281
Securities Available to Be Pledged [Member]
Pledged Securities	21,934
Securities Available to Be Pledged [Member] | Federal Home Loan Bank Borrowings [Member]
Pledged Securities	15,080
Securities Available to Be Pledged [Member] | Public Funds Collateral [Member]
Pledged Securities	$ 6,854