Note 8 - Loans - Impaired Loans and Related Allowance for Credit Losses (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Loans with no related allowance, unpaid principal balance	$ 106,639	$ 77,605
Loans with no related allowance, recorded investment	92,231	65,315
Loans with related allowance, unpaid principal balance	28,462	42,686
Loans with related allowance, recorded investment	27,400	41,571
Allowance	1,414	3,802
Total impaired loans, unpaid principal balance	135,101	120,291
Total impaired loans, recorded investment	119,631	106,886
Commercial Portfolio Segment [Member]
Loans with no related allowance, unpaid principal balance	45,590	32,015
Loans with no related allowance, recorded investment	42,220	30,368
Loans with related allowance, unpaid principal balance	950	6,653
Loans with related allowance, recorded investment	939	6,570
Allowance	498	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	4,801	4,873
Commercial Real Estate Portfolio Segment [Member]
Loans with no related allowance, unpaid principal balance	48,151	34,129
Loans with no related allowance, recorded investment	38,114	24,409
Loans with related allowance, unpaid principal balance	20,289	27,099
Loans with related allowance, recorded investment	20,238	27,063
Allowance	667	877
Residential Mortgage and Equity Lines Portfolio Segment [Member]
Loans with no related allowance, unpaid principal balance	7,122	5,685
Loans with no related allowance, recorded investment	7,096	5,665
Loans with related allowance, unpaid principal balance	7,223	8,934
Loans with related allowance, recorded investment	6,223	7,938
Allowance	$ 249	$ 1,088