Loans and Allowance for Credit Losses - Age Analysis of Past Due Loans, Excluding Loans Acquired, Segregated by Class of Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Financing Receivable, Past Due [Line Items]
Loans	$ 17,336,040	$ 16,845,670
90 Days Past Due & Accruing	830	1,147
Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	47,473	55,666
90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	65,026	42,701
Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	112,499	98,367
Current
Financing Receivable, Past Due [Line Items]
Loans	17,223,541	16,747,303
Consumer
Financing Receivable, Past Due [Line Items]
Loans	291,592	318,666
90 Days Past Due & Accruing	561	791
Consumer | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	2,637	3,205
Consumer | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	910	1,108
Consumer | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	3,547	4,313
Consumer | Current
Financing Receivable, Past Due [Line Items]
Loans	288,045	314,353
Consumer | Credit cards
Financing Receivable, Past Due [Line Items]
Loans	177,696	191,204
90 Days Past Due & Accruing	561	791
Consumer | Credit cards | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	1,535	1,734
Consumer | Credit cards | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	706	892
Consumer | Credit cards | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	2,241	2,626
Consumer | Credit cards | Current
Financing Receivable, Past Due [Line Items]
Loans	175,455	188,578
Consumer | Other consumer
Financing Receivable, Past Due [Line Items]
Loans	113,896	127,462
90 Days Past Due & Accruing	0	0
Consumer | Other consumer | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	1,102	1,471
Consumer | Other consumer | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	204	216
Consumer | Other consumer | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	1,306	1,687
Consumer | Other consumer | Current
Financing Receivable, Past Due [Line Items]
Loans	112,590	125,775
Real Estate
Financing Receivable, Past Due [Line Items]
Loans	13,513,463	13,338,186
90 Days Past Due & Accruing	155	7
Real Estate | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	32,146	38,570
Real Estate | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	39,013	18,324
Real Estate | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	71,159	56,894
Real Estate | Current
Financing Receivable, Past Due [Line Items]
Loans	13,442,304	13,281,292
Real Estate | Construction and development
Financing Receivable, Past Due [Line Items]
Loans	2,796,378	3,144,220
90 Days Past Due & Accruing	0	0
Real Estate | Construction and development | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	4,338	3,171
Real Estate | Construction and development | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	1,438	2,190
Real Estate | Construction and development | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	5,776	5,361
Real Estate | Construction and development | Current
Financing Receivable, Past Due [Line Items]
Loans	2,790,602	3,138,859
Real Estate | Single family residential
Financing Receivable, Past Due [Line Items]
Loans	2,724,648	2,641,556
90 Days Past Due & Accruing	69	7
Real Estate | Single family residential | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	15,647	30,697
Real Estate | Single family residential | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	15,616	12,522
Real Estate | Single family residential | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	31,263	43,219
Real Estate | Single family residential | Current
Financing Receivable, Past Due [Line Items]
Loans	2,693,385	2,598,337
Real Estate | Other commercial
Financing Receivable, Past Due [Line Items]
Loans	7,992,437	7,552,410
90 Days Past Due & Accruing	86	0
Real Estate | Other commercial | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	12,161	4,702
Real Estate | Other commercial | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	21,959	3,612
Real Estate | Other commercial | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	34,120	8,314
Real Estate | Other commercial | Current
Financing Receivable, Past Due [Line Items]
Loans	7,958,317	7,544,096
Commercial
Financing Receivable, Past Due [Line Items]
Loans	2,781,724	2,722,886
90 Days Past Due & Accruing	114	349
Commercial | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	12,413	13,891
Commercial | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	25,100	23,266
Commercial | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	37,513	37,157
Commercial | Current
Financing Receivable, Past Due [Line Items]
Loans	2,744,211	2,685,729
Commercial | Commercial
Financing Receivable, Past Due [Line Items]
Loans	2,467,384	2,490,176
90 Days Past Due & Accruing	114	349
Commercial | Commercial | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	12,407	13,799
Commercial | Commercial | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	24,566	22,750
Commercial | Commercial | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	36,973	36,549
Commercial | Commercial | Current
Financing Receivable, Past Due [Line Items]
Loans	2,430,411	2,453,627
Commercial | Agricultural
Financing Receivable, Past Due [Line Items]
Loans	314,340	232,710
90 Days Past Due & Accruing	0	0
Commercial | Agricultural | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	6	92
Commercial | Agricultural | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	534	516
Commercial | Agricultural | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	540	608
Commercial | Agricultural | Current
Financing Receivable, Past Due [Line Items]
Loans	313,800	232,102
Other
Financing Receivable, Past Due [Line Items]
Loans	749,261	465,932
90 Days Past Due & Accruing	0	0
Other | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	277	0
Other | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	3	3
Other | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	280	3
Other | Current
Financing Receivable, Past Due [Line Items]
Loans	$ 748,981	$ 465,929