Note 6 - Loans and the Allowance for Loan Losses - Past Due Loans Receivable (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Past due	$ 13,955	$ 8,789
Current	2,980,857	1,701,476
Loans	2,994,812	1,710,265
Recorded investment over 90 days past due and still accruing	317	72
Financial Asset, 30 to 59 Days Past Due [Member]
Past due	4,777	2,228
Financial Asset, 60 to 89 Days Past Due [Member]
Past due	571	1,794
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	8,607	4,767
Commercial Real Estate Portfolio Segment [Member] | Construction and Land [Member]
Past due	1,626	879
Current	332,049	243,302
Loans	333,675	244,181
Recorded investment over 90 days past due and still accruing	4	0
Commercial Real Estate Portfolio Segment [Member] | Construction and Land [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due	1,071	483
Commercial Real Estate Portfolio Segment [Member] | Construction and Land [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due	156	17
Commercial Real Estate Portfolio Segment [Member] | Construction and Land [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	399	379
Commercial Real Estate Portfolio Segment [Member] | Farmland [Member]
Past due	402	177
Current	57,096	48,504
Loans	57,498	48,681
Recorded investment over 90 days past due and still accruing	0	0
Commercial Real Estate Portfolio Segment [Member] | Farmland [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due	65	18
Commercial Real Estate Portfolio Segment [Member] | Farmland [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due	0	16
Commercial Real Estate Portfolio Segment [Member] | Farmland [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	337	143
Commercial Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member]
Past due	2,507	2,320
Current	912,094	610,288
Loans	914,601	612,608
Recorded investment over 90 days past due and still accruing	0	0
Commercial Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due	521	181
Commercial Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due	32	610
Commercial Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	1,954	1,529
Residential Portfolio Segment [Member] | Real Estate Residential One- to Four-Family [Member]
Past due	4,522	3,220
Current	491,305	289,922
Loans	495,827	293,142
Recorded investment over 90 days past due and still accruing	277	29
Residential Portfolio Segment [Member] | Real Estate Residential One- to Four-Family [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due	1,958	1,245
Residential Portfolio Segment [Member] | Real Estate Residential One- to Four-Family [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due	150	975
Residential Portfolio Segment [Member] | Real Estate Residential One- to Four-Family [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	2,414	1,000
Residential Portfolio Segment [Member] | Multi-family Residential [Member]
Past due	0	32
Current	59,213	36,422
Loans	59,213	36,454
Recorded investment over 90 days past due and still accruing	0	0
Residential Portfolio Segment [Member] | Multi-family Residential [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due	0	32
Residential Portfolio Segment [Member] | Multi-family Residential [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due	0	0
Residential Portfolio Segment [Member] | Multi-family Residential [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	0	0
Commercial Portfolio Segment [Member]
Past due	4,208	1,579
Current	1,022,388	388,819
Loans	1,026,596	390,398
Recorded investment over 90 days past due and still accruing	24	0
Commercial Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due	997	126
Commercial Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due	164	142
Commercial Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	3,047	1,311
Consumer Portfolio Segment [Member]
Past due	690	582
Current	106,712	84,219
Loans	107,402	84,801
Recorded investment over 90 days past due and still accruing	12	43
Consumer Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due	165	143
Consumer Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due	69	34
Consumer Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	$ 456	$ 405