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	Jun. 30, 2022	Dec. 31, 2021
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	$ 10,944,840	$ 10,247,829
Total LHFI	10,944,840	10,247,829
Past Due 30 to 59 Days [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	13,774	8,310
Past Due 60 to 89 Days [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	7,408	1,165
Past Due 90 Days or More [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	6,865	15,819
Financial Asset, Past Due [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	28,047	25,294
Current Loans
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	10,916,793	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	664,817	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)	581	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)	164	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)	47	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)	792	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)	664,025	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	540,950	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)	2,530	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)	368	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)	1,060	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)	3,958	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)	536,992	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	1,884,012	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)	3,384	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)	2,605	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)	4,630	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)	10,619	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)	1,873,393	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)	3,178,079	2,977,084
Total LHFI	3,178,079	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)	4,923	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)	3,713
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)	419	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)	9,055	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)	3,169,024	2,974,797
Other Real Estate Secured [Member] | Loans Secured by Real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Total LHFI	555,311	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)	196
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)	7
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)	203	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)	555,108	725,901
Commercial and Industrial Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	1,551,001	1,414,279
Total LHFI	1,551,001	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)	994	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)	264	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)	269	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)	1,527	1,755
Commercial and Industrial Loans [Member] | Current Loans
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	1,549,474	1,412,524
Other Construction [Member] | Other Loans Secured by Real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Total LHFI	775,241	711,813
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)	775,241	711,813
Consumer Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	164,001	162,555
Total LHFI	164,001	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)	966	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)	247	182
Consumer Loans [Member] | Past Due 90 Days or More [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	204	305
Consumer Loans [Member] | Financial Asset, Past Due [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	1,417	2,160
Consumer Loans [Member] | Current Loans
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	162,584	160,395
State and Other Political Subdivision Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	1,110,795	1,146,251
Total LHFI	1,110,795	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)		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)	177	209
State and Other Political Subdivision Loans [Member] | Current Loans
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	1,110,618	1,146,042
Other Commercial Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	520,633	534,843
Total LHFI	520,633	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)	200	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)	40	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)	59	118
Other Commercial Loans [Member] | Financial Asset, Past Due [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	299	370
Other Commercial Loans [Member] | Current Loans
Financing Receivable Allowance For Credit Losses [Line Items]
Loans held for investment (LHFI)	$ 520,334	$ 534,473