Note 8 - Loans - Impaired Loans and Related Allowance for Credit Losses (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Loans with no related allowance, unpaid principal balance	$ 91,251	$ 77,605
Loans with no related allowance, recorded investment	75,395	65,315
Loans with related allowance, unpaid principal balance	45,393	42,686
Loans with related allowance, recorded investment	44,251	41,571
Allowance	1,686	3,802
Total impaired loans, unpaid principal balance	136,644	120,291
Total impaired loans, recorded investment	119,646	106,886
Commercial Portfolio Segment [Member]
Loans with no related allowance, unpaid principal balance	45,022	32,015
Loans with no related allowance, recorded investment	40,260	30,368
Loans with related allowance, unpaid principal balance	12,577	6,653
Loans with related allowance, recorded investment	12,563	6,570
Allowance	832	1,837
Real Estate Construction Portfolio Segment [Member]
Loans with no related allowance, unpaid principal balance	5,776	5,776
Loans with no related allowance, recorded investment	4,702	4,873
Commercial Real Estate Portfolio Segment [Member]
Loans with no related allowance, unpaid principal balance	33,410	34,129
Loans with no related allowance, recorded investment	23,436	24,409
Loans with related allowance, unpaid principal balance	25,761	27,099
Loans with related allowance, recorded investment	25,704	27,063
Allowance	620	877
Residential Mortgage and Equity Lines Portfolio Segment [Member]
Loans with no related allowance, unpaid principal balance	7,043	5,685
Loans with no related allowance, recorded investment	6,997	5,665
Loans with related allowance, unpaid principal balance	7,055	8,934
Loans with related allowance, recorded investment	5,984	7,938
Allowance	$ 234	$ 1,088