Note 8 - Loans - Impaired Loans and Related Allowance for Credit Losses (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Loans with no related allowance, unpaid principal balance	$ 47,443	$ 58,816
Loans with no related allowance, recorded investment	41,153	53,578
Loans with related allowance, unpaid principal balance	38,295	49,842
Loans with related allowance, recorded investment	27,529	41,827
Allowance	6,530	6,429
Unpaid principal balance	85,738	108,658
Recorded investment	68,682	95,405
Commercial Portfolio Segment [Member]
Loans with no related allowance, unpaid principal balance	13,897	23,784
Loans with no related allowance, recorded investment	10,442	20,698
Loans with related allowance, unpaid principal balance	16,739	13,703
Loans with related allowance, recorded investment	6,656	6,372
Allowance	1,301	1,030
Real Estate Construction Portfolio Segment [Member]
Loans with no related allowance, unpaid principal balance	7,201	5,776
Loans with no related allowance, recorded investment	5,491	4,286
Commercial Real Estate Portfolio Segment [Member]
Loans with no related allowance, unpaid principal balance	19,356	22,877
Loans with no related allowance, recorded investment	18,407	22,287
Loans with related allowance, unpaid principal balance	18,664	31,134
Loans with related allowance, recorded investment	18,561	31,003
Allowance	5,229	5,254
Residential Mortgage and Equity Lines Portfolio Segment [Member]
Loans with no related allowance, unpaid principal balance	6,989	6,379
Loans with no related allowance, recorded investment	6,813	6,307
Loans with related allowance, unpaid principal balance	2,892	5,005
Loans with related allowance, recorded investment	2,312	4,452
Allowance	$ 0	$ 145