Note 6 - Loans Receivable and Allowance for Loan Losses - Past Due Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Loans receivable, total past due	$ 14,332	$ 14,348
Loans receivable, current	2,630,682	1,733,748
Loans receivable	2,645,014	1,748,096
Loans receivable greater than 90 days and accruing	0	0
Financial Asset, 30 to 59 Days Past Due [Member]
Loans receivable, total past due	1,025	112
Financial Asset, 60 to 89 Days Past Due [Member]
Loans receivable, total past due	858	1,823
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans receivable, total past due	12,449	12,413
Commercial Real Estate Portfolio Segment [Member]
Loans receivable, total past due	4,584	4,472
Loans receivable, current	671,876	609,159
Loans receivable	676,460	613,631
Loans receivable greater than 90 days and accruing	0	0
Commercial Real Estate Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Loans receivable, total past due	0	0
Commercial Real Estate Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Loans receivable, total past due	6	313
Commercial Real Estate Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans receivable, total past due	4,578	4,159
Construction and Land Development Portfolio Segment [Member]
Loans receivable, total past due	0	0
Loans receivable, current	164,671	121,395
Loans receivable	164,671	121,395
Loans receivable greater than 90 days and accruing	0	0
Construction and Land Development Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Loans receivable, total past due	0	0
Construction and Land Development Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Loans receivable, total past due	0	0
Construction and Land Development Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans receivable, total past due	0	0
Commercial Portfolio Segment [Member]
Loans receivable, total past due	2,972	3,137
Loans receivable, current	225,173	220,769
Loans receivable	228,145	223,906
Loans receivable greater than 90 days and accruing	0	0
Commercial Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Loans receivable, total past due	0	0
Commercial Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Loans receivable, total past due	0	50
Commercial Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans receivable, total past due	2,972	3,087
Owner Occupied Real Estate [Member]
Loans receivable, total past due	3,714	4,556
Loans receivable, current	423,312	419,844
Loans receivable	427,026	424,400
Loans receivable greater than 90 days and accruing	0	0
Owner Occupied Real Estate [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Loans receivable, total past due	0	0
Owner Occupied Real Estate [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Loans receivable, total past due	611	1,219
Owner Occupied Real Estate [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans receivable, total past due	3,103	3,337
Consumer Portfolio Segment [Member]
Loans receivable, total past due	1,804	1,415
Loans receivable, current	98,231	99,905
Loans receivable	100,035	101,320
Loans receivable greater than 90 days and accruing	0	0
Consumer Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Loans receivable, total past due	468	112
Consumer Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Loans receivable, total past due	241	241
Consumer Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans receivable, total past due	1,095	1,062
Residential Portfolio Segment [Member]
Loans receivable, total past due	1,258	768
Loans receivable, current	364,021	262,676
Loans receivable	365,279	263,444
Loans receivable greater than 90 days and accruing	0	0
Residential Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Loans receivable, total past due	557	0
Residential Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Loans receivable, total past due	0	0
Residential Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans receivable, total past due	701	768
Paycheck Protection Program CARES Act [Member]
Loans receivable, total past due	0
Loans receivable, current	683,398
Loans receivable	683,398	$ 0
Loans receivable greater than 90 days and accruing	0
Paycheck Protection Program CARES Act [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Loans receivable, total past due	0
Paycheck Protection Program CARES Act [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Loans receivable, total past due	0
Paycheck Protection Program CARES Act [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans receivable, total past due	$ 0