Note 5 - Loans - Impaired Loans and Related Allowance for Credit Losses (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Loans with no related allowance, unpaid principal balance	$ 77,605	$ 91,430
Loans with no related allowance, recorded investment	65,315	83,217
Loans with related allowance, unpaid principal balance	42,686	35,646
Loans with related allowance, recorded investment	41,571	34,136
Allowance	3,802	2,134
Total impaired loans, unpaid principal balance	120,291	127,076
Total impaired loans, recorded investment	106,886	117,353
Commercial Portfolio Segment [Member]
Loans with no related allowance, unpaid principal balance	32,015	43,483
Loans with no related allowance, recorded investment	30,368	42,702
Loans with related allowance, unpaid principal balance	6,653	891
Loans with related allowance, recorded investment	6,570	793
Allowance	1,837	43
Real Estate Construction Portfolio Segment [Member]
Loans with no related allowance, unpaid principal balance	5,776	8,821
Loans with no related allowance, recorded investment	4,873	8,185
Commercial Real Estate Portfolio Segment [Member]
Loans with no related allowance, unpaid principal balance	34,129	37,825
Loans with no related allowance, recorded investment	24,409	31,029
Loans with related allowance, unpaid principal balance	27,099	21,733
Loans with related allowance, recorded investment	27,063	21,635
Allowance	877	1,738
Residential Mortgage and Equity Lines Portfolio Segment [Member]
Loans with no related allowance, unpaid principal balance	5,685	1,301
Loans with no related allowance, recorded investment	5,665	1,301
Loans with related allowance, unpaid principal balance	8,934	13,022
Loans with related allowance, recorded investment	7,938	11,708
Allowance	$ 1,088	$ 353