Note 8 - Loans - Impaired Loans and Related Allowance for Credit Losses (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Loans with no related allowance, unpaid principal balance	$ 47,817	$ 41,315
Loans with no related allowance, recorded investment	43,223	35,540
Loans with related allowance, unpaid principal balance	46,005	41,626
Loans with related allowance, recorded investment	44,906	40,319
Allowance	7,525	3,236
Total impaired loans, unpaid principal balance	93,822	82,941
Total impaired loans, recorded investment	88,129	75,859
Commercial Portfolio Segment [Member]
Loans with no related allowance, unpaid principal balance	16,181	20,134
Loans with no related allowance, recorded investment	13,391	15,857
Loans with related allowance, unpaid principal balance	15,919	8,769
Loans with related allowance, recorded investment	15,863	8,739
Allowance	6,895	2,543
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	4,433	4,580
Commercial Real Estate Portfolio Segment [Member]
Loans with no related allowance, unpaid principal balance	16,274	9,234
Loans with no related allowance, recorded investment	15,867	9,030
Loans with related allowance, unpaid principal balance	19,806	26,117
Loans with related allowance, recorded investment	19,762	26,040
Allowance	323	473
Residential Mortgage and Equity Lines Portfolio Segment [Member]
Loans with no related allowance, unpaid principal balance	9,586	6,171
Loans with no related allowance, recorded investment	9,532	6,073
Loans with related allowance, unpaid principal balance	10,280	6,740
Loans with related allowance, recorded investment	9,281	5,540
Allowance	$ 307	$ 220