Loans and Allowance for Credit Losses - Age Analysis of Past Due Loans, Excluding Loans Acquired, Segregated by Class of Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Financing Receivable, Past Due [Line Items]
Loans	$ 16,555,098	$ 16,142,124
90 Days Past Due & Accruing	437	507
Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	36,309	38,416
90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	29,474	26,886
Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	65,783	65,302
Current
Financing Receivable, Past Due [Line Items]
Loans	16,489,315	16,076,822
Consumer
Financing Receivable, Past Due [Line Items]
Loans	331,407	349,810
90 Days Past Due & Accruing	301	225
Consumer | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	2,665	2,149
Consumer | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	693	623
Consumer | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	3,358	2,772
Consumer | Current
Financing Receivable, Past Due [Line Items]
Loans	328,049	347,038
Consumer | Credit cards
Financing Receivable, Past Due [Line Items]
Loans	188,590	196,928
90 Days Past Due & Accruing	301	225
Consumer | Credit cards | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	1,695	1,297
Consumer | Credit cards | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	385	409
Consumer | Credit cards | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	2,080	1,706
Consumer | Credit cards | Current
Financing Receivable, Past Due [Line Items]
Loans	186,510	195,222
Consumer | Other consumer
Financing Receivable, Past Due [Line Items]
Loans	142,817	152,882
90 Days Past Due & Accruing	0	0
Consumer | Other consumer | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	970	852
Consumer | Other consumer | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	308	214
Consumer | Other consumer | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	1,278	1,066
Consumer | Other consumer | Current
Financing Receivable, Past Due [Line Items]
Loans	141,539	151,816
Real Estate
Financing Receivable, Past Due [Line Items]
Loans	12,887,917	12,581,262
90 Days Past Due & Accruing	0	106
Real Estate | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	23,246	31,061
Real Estate | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	17,508	18,618
Real Estate | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	40,754	49,679
Real Estate | Current
Financing Receivable, Past Due [Line Items]
Loans	12,847,163	12,531,583
Real Estate | Construction and development
Financing Receivable, Past Due [Line Items]
Loans	2,777,122	2,566,649
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	383	4,677
Real Estate | Construction and development | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	4,384	443
Real Estate | Construction and development | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	4,767	5,120
Real Estate | Construction and development | Current
Financing Receivable, Past Due [Line Items]
Loans	2,772,355	2,561,529
Real Estate | Single family residential
Financing Receivable, Past Due [Line Items]
Loans	2,589,831	2,546,115
90 Days Past Due & Accruing	0	106
Real Estate | Single family residential | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	19,220	23,625
Real Estate | Single family residential | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	9,415	11,075
Real Estate | Single family residential | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	28,635	34,700
Real Estate | Single family residential | Current
Financing Receivable, Past Due [Line Items]
Loans	2,561,196	2,511,415
Real Estate | Other commercial
Financing Receivable, Past Due [Line Items]
Loans	7,520,964	7,468,498
90 Days Past Due & Accruing	0	0
Real Estate | Other commercial | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	3,643	2,759
Real Estate | Other commercial | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	3,709	7,100
Real Estate | Other commercial | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	7,352	9,859
Real Estate | Other commercial | Current
Financing Receivable, Past Due [Line Items]
Loans	7,513,612	7,458,639
Commercial
Financing Receivable, Past Due [Line Items]
Loans	2,890,372	2,837,913
90 Days Past Due & Accruing	136	176
Commercial | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	10,398	5,145
Commercial | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	11,270	7,642
Commercial | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	21,668	12,787
Commercial | Current
Financing Receivable, Past Due [Line Items]
Loans	2,868,704	2,825,126
Commercial | Commercial
Financing Receivable, Past Due [Line Items]
Loans	2,669,731	2,632,290
90 Days Past Due & Accruing	136	176
Commercial | Commercial | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	10,170	5,034
Commercial | Commercial | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	11,248	7,575
Commercial | Commercial | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	21,418	12,609
Commercial | Commercial | Current
Financing Receivable, Past Due [Line Items]
Loans	2,648,313	2,619,681
Commercial | Agricultural
Financing Receivable, Past Due [Line Items]
Loans	220,641	205,623
90 Days Past Due & Accruing	0	0
Commercial | Agricultural | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	228	111
Commercial | Agricultural | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	22	67
Commercial | Agricultural | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	250	178
Commercial | Agricultural | Current
Financing Receivable, Past Due [Line Items]
Loans	220,391	205,445
Other
Financing Receivable, Past Due [Line Items]
Loans	445,402	373,139
90 Days Past Due & Accruing	0	0
Other | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	0	61
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	3	64
Other | Current
Financing Receivable, Past Due [Line Items]
Loans	$ 445,399	$ 373,075