Note 8 - Loans - Impaired Loans and Related Allowance for Credit Losses (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Loans with no related allowance, unpaid principal balance	$ 72,959	$ 58,816
Loans with no related allowance, recorded investment	58,467	53,578
Loans with related allowance, unpaid principal balance	36,097	49,842
Loans with related allowance, recorded investment	35,979	41,827
Allowance	10,692	6,429
Unpaid principal balance	109,056	108,658
Recorded investment	94,446	95,405
Commercial Portfolio Segment [Member]
Loans with no related allowance, unpaid principal balance	30,111	23,784
Loans with no related allowance, recorded investment	18,534	20,698
Loans with related allowance, unpaid principal balance	19,864	13,703
Loans with related allowance, recorded investment	19,817	6,372
Allowance	5,559	1,030
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	4,189	4,286
Commercial Real Estate Portfolio Segment [Member]
Loans with no related allowance, unpaid principal balance	27,867	22,877
Loans with no related allowance, recorded investment	27,199	22,287
Loans with related allowance, unpaid principal balance	16,233	31,134
Loans with related allowance, recorded investment	16,162	31,003
Allowance	5,133	5,254
Residential Mortgage and Equity Lines Portfolio Segment [Member]
Loans with no related allowance, unpaid principal balance	9,205	6,379
Loans with no related allowance, recorded investment	$ 8,545	6,307
Loans with related allowance, unpaid principal balance		5,005
Loans with related allowance, recorded investment		4,452
Allowance		$ 145