Loans Held for Investment (LHFI) and Allowance for Loan Losses, LHFI - Aging Analysis of Past Due and Nonaccrual LHFI by Loan Type (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	$ 11,586,064	$ 10,247,829
Total LHFI	11,586,064	10,247,829
Past Due 30 to 59 Days [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	16,210	8,310
Past Due 60 to 89 Days [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	8,184	1,165
Past Due 90 Days or More [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	17,600	15,819
Financial Asset, Past Due [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	41,994	25,294
Current Loans
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	11,544,070	10,222,535
Construction, Land Development and Other Land [Member] | Loans Secured by Real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Total LHFI	693,741	596,968
Construction, Land Development and Other Land [Member] | Loans Secured by Real Estate [Member] | Past Due 30 to 59 Days [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	638	323
Construction, Land Development and Other Land [Member] | Loans Secured by Real Estate [Member] | Past Due 60 to 89 Days [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	4,047	11
Construction, Land Development and Other Land [Member] | Loans Secured by Real Estate [Member] | Past Due 90 Days or More [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	159	5,241
Construction, Land Development and Other Land [Member] | Loans Secured by Real Estate [Member] | Financial Asset, Past Due [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	4,844	5,575
Construction, Land Development and Other Land [Member] | Loans Secured by Real Estate [Member] | Current Loans
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	688,897	591,393
Other Secured by 1-4 Family Residential Properties [Member] | Loans Secured by Real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Total LHFI	566,985	517,683
Other Secured by 1-4 Family Residential Properties [Member] | Loans Secured by Real Estate [Member] | Past Due 30 to 59 Days [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	2,490	1,811
Other Secured by 1-4 Family Residential Properties [Member] | Loans Secured by Real Estate [Member] | Past Due 60 to 89 Days [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	559	368
Other Secured by 1-4 Family Residential Properties [Member] | Loans Secured by Real Estate [Member] | Past Due 90 Days or More [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	862	567
Other Secured by 1-4 Family Residential Properties [Member] | Loans Secured by Real Estate [Member] | Financial Asset, Past Due [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	3,911	2,746
Other Secured by 1-4 Family Residential Properties [Member] | Loans Secured by Real Estate [Member] | Current Loans
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	563,074	514,937
Secured by 1-4 Family Residential Properties [Member] | Other Loans Secured by Real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Total LHFI	2,030,127	1,460,310
Secured by 1-4 Family Residential Properties [Member] | Other Loans Secured by Real Estate [Member] | Past Due 30 to 59 Days [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	8,161	2,799
Secured by 1-4 Family Residential Properties [Member] | Other Loans Secured by Real Estate [Member] | Past Due 60 to 89 Days [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	3,066	531
Secured by 1-4 Family Residential Properties [Member] | Other Loans Secured by Real Estate [Member] | Past Due 90 Days or More [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	5,437	6,720
Secured by 1-4 Family Residential Properties [Member] | Other Loans Secured by Real Estate [Member] | Financial Asset, Past Due [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	16,664	10,050
Secured by 1-4 Family Residential Properties [Member] | Other Loans Secured by Real Estate [Member] | Current Loans
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	2,013,463	1,450,260
Secured by Nonfarm, Nonresidential Properties [Member] | Loans Secured by Real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	3,206,946	2,977,084
Total LHFI	3,206,946	2,977,084
Secured by Nonfarm, Nonresidential Properties [Member] | Loans Secured by Real Estate [Member] | Past Due 30 to 59 Days [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	1,039	845
Secured by Nonfarm, Nonresidential Properties [Member] | Loans Secured by Real Estate [Member] | Past Due 60 to 89 Days [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	0
Secured by Nonfarm, Nonresidential Properties [Member] | Loans Secured by Real Estate [Member] | Past Due 90 Days or More [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	1,948	1,442
Secured by Nonfarm, Nonresidential Properties [Member] | Loans Secured by Real Estate [Member] | Financial Asset, Past Due [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	2,987	2,287
Secured by Nonfarm, Nonresidential Properties [Member] | Loans Secured by Real Estate [Member] | Current Loans
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	3,203,959	2,974,797
Other Real Estate Secured [Member] | Loans Secured by Real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Total LHFI	593,119	726,043
Other Real Estate Secured [Member] | Loans Secured by Real Estate [Member] | Past Due 30 to 59 Days [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	440
Other Real Estate Secured [Member] | Loans Secured by Real Estate [Member] | Past Due 60 to 89 Days [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	48
Other Real Estate Secured [Member] | Loans Secured by Real Estate [Member] | Past Due 90 Days or More [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)		142
Other Real Estate Secured [Member] | Loans Secured by Real Estate [Member] | Financial Asset, Past Due [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	488	142
Other Real Estate Secured [Member] | Loans Secured by Real Estate [Member] | Current Loans
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	592,631	725,901
Commercial and Industrial Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	1,689,532	1,414,279
Total LHFI	1,689,532	1,414,279
Commercial and Industrial Loans [Member] | Past Due 30 to 59 Days [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	1,592	607
Commercial and Industrial Loans [Member] | Past Due 60 to 89 Days [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	45	41
Commercial and Industrial Loans [Member] | Past Due 90 Days or More [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	790	1,107
Commercial and Industrial Loans [Member] | Financial Asset, Past Due [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	2,427	1,755
Commercial and Industrial Loans [Member] | Current Loans
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	1,687,105	1,412,524
Other Construction [Member] | Other Loans Secured by Real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Total LHFI	953,654	711,813
Other Construction [Member] | Other Loans Secured by Real Estate [Member] | Past Due 90 Days or More [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	7,620
Other Construction [Member] | Other Loans Secured by Real Estate [Member] | Financial Asset, Past Due [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	7,620
Other Construction [Member] | Other Loans Secured by Real Estate [Member] | Current Loans
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	946,034	711,813
Consumer Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	166,027	162,555
Total LHFI	166,027	162,555
Consumer Loans [Member] | Past Due 30 to 59 Days [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	1,329	1,673
Consumer Loans [Member] | Past Due 60 to 89 Days [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	390	182
Consumer Loans [Member] | Past Due 90 Days or More [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	417	305
Consumer Loans [Member] | Financial Asset, Past Due [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	2,136	2,160
Consumer Loans [Member] | Current Loans
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	163,891	160,395
State and Other Political Subdivision Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	1,188,703	1,146,251
Total LHFI	1,188,703	1,146,251
State and Other Political Subdivision Loans [Member] | Past Due 30 to 59 Days [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	143	32
State and Other Political Subdivision Loans [Member] | Past Due 90 Days or More [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	177	177
State and Other Political Subdivision Loans [Member] | Financial Asset, Past Due [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	320	209
State and Other Political Subdivision Loans [Member] | Current Loans
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	1,188,383	1,146,042
Other Commercial Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	497,230	534,843
Total LHFI	497,230	534,843
Other Commercial Loans [Member] | Past Due 30 to 59 Days [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	378	220
Other Commercial Loans [Member] | Past Due 60 to 89 Days [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	29	32
Other Commercial Loans [Member] | Past Due 90 Days or More [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	190	118
Other Commercial Loans [Member] | Financial Asset, Past Due [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	597	370
Other Commercial Loans [Member] | Current Loans
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	$ 496,633	$ 534,473