Note 4 - Loans - Past Due Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Past due	$ 4,157	$ 4,626
90 days past due and still accruing	375	361
Nonaccrual loans	2,855	1,944
Current	2,097,554	1,826,189
Loans and Leases Receivable, Net of Deferred Income, Total	2,101,711	1,830,815
Financial Asset, 30 to 59 Days Past Due [Member]
Past due	584	1,361
Financial Asset, 60 to 89 Days Past Due [Member]
Past due	343	960
Commercial Portfolio Segment [Member]
Past due	292	1,397
90 days past due and still accruing	13	52
Nonaccrual loans	260	857
Current	566,567	337,680
Loans and Leases Receivable, Net of Deferred Income, Total	566,859	339,077
Commercial Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due	19	325
Commercial Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due	0	163
Commercial Real Estate Portfolio Segment [Member]
Loans and Leases Receivable, Net of Deferred Income, Total	1,120,160	1,037,119
Commercial Real Estate Portfolio Segment [Member] | Construction and Land Development [Member]
Past due	8	69
90 days past due and still accruing	0	0
Nonaccrual loans	8	11
Current	141,384	137,851
Loans and Leases Receivable, Net of Deferred Income, Total	141,392	137,920
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate [Member]
Past due	1,962	925
90 days past due and still accruing	212	0
Nonaccrual loans	1,662	274
Current	976,806	898,274
Loans and Leases Receivable, Net of Deferred Income, Total	978,768	899,199
Commercial Real Estate Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Construction and Land Development [Member]
Past due	0	58
Commercial Real Estate Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Real Estate [Member]
Past due	0	217
Commercial Real Estate Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Construction and Land Development [Member]
Past due	0	0
Commercial Real Estate Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Real Estate [Member]
Past due	88	434
Residential Portfolio Segment [Member]
Loans and Leases Receivable, Net of Deferred Income, Total	405,639	443,738
Residential Portfolio Segment [Member] | Residential [Member]
Past due	1,327	1,866
90 days past due and still accruing	125	282
Nonaccrual loans	750	685
Current	289,915	322,449
Loans and Leases Receivable, Net of Deferred Income, Total	291,242	324,315
Residential Portfolio Segment [Member] | Home Equity Line of Credit [Member]
Past due	539	279
90 days past due and still accruing	25	27
Nonaccrual loans	174	113
Current	113,858	119,144
Loans and Leases Receivable, Net of Deferred Income, Total	114,397	119,423
Residential Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Residential [Member]
Past due	202	639
Residential Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Home Equity Line of Credit [Member]
Past due	340	49
Residential Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Residential [Member]
Past due	250	260
Residential Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Home Equity Line of Credit [Member]
Past due	0	90
Consumer Portfolio Segment [Member]
Past due	29	90
90 days past due and still accruing	0	0
Nonaccrual loans	1	4
Current	9,024	10,791
Loans and Leases Receivable, Net of Deferred Income, Total	9,053	10,881
Consumer Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due	23	73
Consumer Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due	$ 5	$ 13