Note 5 - Loans and Allowance for Loan Losses - Aging of Recorded Investment (Details) - USD ($) $ in Thousands		Sep. 30, 2020	Dec. 31, 2019
Total Past Due		$ 35,922	$ 15,830
Loans Not Past Due		2,719,231	2,181,104
Total Loans	[1]	2,755,153	2,196,934
Non-accrual Loans		15,993	11,437	[2]
Financial Asset, 30 to 59 Days Past Due [Member]
Total Past Due		9,998	3,717
Financial Asset, 60 to 89 Days Past Due [Member]
Total Past Due		13,019	1,560
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Total Past Due		12,905	10,553
Commercial Real Estate Portfolio Segment [Member] | Construction And Land Development Loans [Member]
Total Past Due		761	0
Loans Not Past Due		182,808	96,020
Total Loans	[1]	183,569	96,020
Non-accrual Loans	[2]	761	0
Commercial Real Estate Portfolio Segment [Member] | Construction And Land Development Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Total Past Due		0	0
Commercial Real Estate Portfolio Segment [Member] | Construction And Land Development Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Total Past Due		400	0
Commercial Real Estate Portfolio Segment [Member] | Construction And Land Development Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Total Past Due		361	0
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate [Member]
Total Past Due		20,537	725
Loans Not Past Due		954,650	792,543
Total Loans		975,187	793,268
Non-accrual Loans	[2]	1,168	725
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Total Past Due		7,578	0
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Total Past Due		11,791	0
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Total Past Due		1,168	725
Commercial Real Estate Portfolio Segment [Member] | Single Family Residential Mortgages Loans [Member]
Total Past Due		3,998	3,464
Loans Not Past Due		1,159,984	953,790
Total Loans	[1]	1,163,982	957,254
Non-accrual Loans	[2]	2,747	1,334
Commercial Real Estate Portfolio Segment [Member] | Single Family Residential Mortgages Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Total Past Due		2,408	1,454
Commercial Real Estate Portfolio Segment [Member] | Single Family Residential Mortgages Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Total Past Due		791	1,560
Commercial Real Estate Portfolio Segment [Member] | Single Family Residential Mortgages Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Total Past Due		799	450
Commercial Portfolio Segment [Member] | Other Loans [Member]
Total Past Due		882	0
Loans Not Past Due		317,009	274,586
Total Loans	[1]	317,891	274,586
Non-accrual Loans	[2]	1,622	0
Commercial Portfolio Segment [Member] | Other Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Total Past Due		0	0
Commercial Portfolio Segment [Member] | Other Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Total Past Due		0	0
Commercial Portfolio Segment [Member] | Other Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Total Past Due		882	0
Commercial Portfolio Segment [Member] | Small Business Administration Agency Securities [Member]
Total Past Due		9,717	11,641
Loans Not Past Due		101,476	63,344
Total Loans	[1]	111,193	74,985
Non-accrual Loans	[2]	9,680	9,378
Commercial Portfolio Segment [Member] | Small Business Administration Agency Securities [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Total Past Due		0	2,263
Commercial Portfolio Segment [Member] | Small Business Administration Agency Securities [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Total Past Due		37	0
Commercial Portfolio Segment [Member] | Small Business Administration Agency Securities [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Total Past Due		9,680	9,378
Other Financing Receivables [Member]
Total Past Due		27	0
Loans Not Past Due		3,304	821
Total Loans	[1]	3,331	821
Non-accrual Loans	[2]	15	0
Other Financing Receivables [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Total Past Due		12	0
Other Financing Receivables [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Total Past Due		0	0
Other Financing Receivables [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Total Past Due		$ 15	$ 0

[1] Loans, net of deferred fees

[2] Included in total loans.