Note 5 - Allowances for Loan Losses - Non-accrual Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Non-accrual loans	$ 14,845	$ 18,594
Commercial Real Estate Portfolio Segment [Member]
Non-accrual loans	8,963	13,089
Construction and Land Development Portfolio Segment [Member]
Non-accrual loans
Commercial Portfolio Segment [Member]
Non-accrual loans	2,895	3,151
Owner Occupied Real Estate [Member]
Non-accrual loans	2,136	1,546
Consumer Portfolio Segment [Member]
Non-accrual loans	851	808
Residential Portfolio Segment [Member]
Non-accrual loans