Note 7 - Fair Value of Financial Instruments - Assets Measured on a Nonrecurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Assets measured on a nonrecurring basis	$ 16,673	$ 14,061
Fair Value, Inputs, Level 1 [Member]
Assets measured on a nonrecurring basis
Fair Value, Inputs, Level 2 [Member]
Assets measured on a nonrecurring basis	16,673	14,061
Fair Value, Inputs, Level 3 [Member]
Assets measured on a nonrecurring basis
Impaired Loans [Member]
Assets measured on a nonrecurring basis	16,406	12,865
Impaired Loans [Member] | Fair Value, Inputs, Level 1 [Member]
Assets measured on a nonrecurring basis
Impaired Loans [Member] | Fair Value, Inputs, Level 2 [Member]
Assets measured on a nonrecurring basis	16,406	12,865
Impaired Loans [Member] | Fair Value, Inputs, Level 3 [Member]
Assets measured on a nonrecurring basis
Repossessed Assets [Member]
Assets measured on a nonrecurring basis	267	1,196
Repossessed Assets [Member] | Fair Value, Inputs, Level 1 [Member]
Assets measured on a nonrecurring basis
Repossessed Assets [Member] | Fair Value, Inputs, Level 2 [Member]
Assets measured on a nonrecurring basis	267	1,196
Repossessed Assets [Member] | Fair Value, Inputs, Level 3 [Member]
Assets measured on a nonrecurring basis