Note 8 - Fair Value of Financial Instruments - Assets Measured on a Nonrecurring Basis (Details) - Fair Value, Nonrecurring [Member] - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Assets measured on a nonrecurring basis	$ 21,772	$ 23,477
Fair Value, Inputs, Level 1 [Member]
Assets measured on a nonrecurring basis
Fair Value, Inputs, Level 2 [Member]
Assets measured on a nonrecurring basis	21,772	23,477
Fair Value, Inputs, Level 3 [Member]
Assets measured on a nonrecurring basis
Impaired Loans [Member]
Assets measured on a nonrecurring basis	20,078	21,557
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	20,078	21,557
Impaired Loans [Member] | Fair Value, Inputs, Level 3 [Member]
Assets measured on a nonrecurring basis
Repossessed Assets [Member]
Assets measured on a nonrecurring basis	1,694	1,920
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	1,694	1,920
Repossessed Assets [Member] | Fair Value, Inputs, Level 3 [Member]
Assets measured on a nonrecurring basis