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, 2023	Dec. 31, 2022
Financing Receivable, Past Due [Line Items]
Loans	$ 16,771,888	$ 16,142,124
90 Days Past Due & Accruing	806	507
Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	28,385	38,416
90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	38,900	26,886
Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	67,285	65,302
Current
Financing Receivable, Past Due [Line Items]
Loans	16,704,603	16,076,822
Consumer
Financing Receivable, Past Due [Line Items]
Loans	304,382	349,810
90 Days Past Due & Accruing	588	225
Consumer | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	3,087	2,149
Consumer | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	924	623
Consumer | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	4,011	2,772
Consumer | Current
Financing Receivable, Past Due [Line Items]
Loans	300,371	347,038
Consumer | Credit cards
Financing Receivable, Past Due [Line Items]
Loans	191,550	196,928
90 Days Past Due & Accruing	588	225
Consumer | Credit cards | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	1,973	1,297
Consumer | Credit cards | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	672	409
Consumer | Credit cards | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	2,645	1,706
Consumer | Credit cards | Current
Financing Receivable, Past Due [Line Items]
Loans	188,905	195,222
Consumer | Other consumer
Financing Receivable, Past Due [Line Items]
Loans	112,832	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	1,114	852
Consumer | Other consumer | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	252	214
Consumer | Other consumer | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	1,366	1,066
Consumer | Other consumer | Current
Financing Receivable, Past Due [Line Items]
Loans	111,466	151,816
Real Estate
Financing Receivable, Past Due [Line Items]
Loans	13,245,208	12,581,262
90 Days Past Due & Accruing	121	106
Real Estate | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	19,311	31,061
Real Estate | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	17,355	18,618
Real Estate | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	36,666	49,679
Real Estate | Current
Financing Receivable, Past Due [Line Items]
Loans	13,208,542	12,531,583
Real Estate | Construction and development
Financing Receivable, Past Due [Line Items]
Loans	3,022,321	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	481	4,677
Real Estate | Construction and development | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	2,742	443
Real Estate | Construction and development | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	3,223	5,120
Real Estate | Construction and development | Current
Financing Receivable, Past Due [Line Items]
Loans	3,019,098	2,561,529
Real Estate | Single family residential
Financing Receivable, Past Due [Line Items]
Loans	2,657,879	2,546,115
90 Days Past Due & Accruing	121	106
Real Estate | Single family residential | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	13,255	23,625
Real Estate | Single family residential | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	11,846	11,075
Real Estate | Single family residential | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	25,101	34,700
Real Estate | Single family residential | Current
Financing Receivable, Past Due [Line Items]
Loans	2,632,778	2,511,415
Real Estate | Other commercial
Financing Receivable, Past Due [Line Items]
Loans	7,565,008	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	5,575	2,759
Real Estate | Other commercial | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	2,767	7,100
Real Estate | Other commercial | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	8,342	9,859
Real Estate | Other commercial | Current
Financing Receivable, Past Due [Line Items]
Loans	7,556,666	7,458,639
Commercial
Financing Receivable, Past Due [Line Items]
Loans	2,773,989	2,837,913
90 Days Past Due & Accruing	97	176
Commercial | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	5,987	5,145
Commercial | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	20,618	7,642
Commercial | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	26,605	12,787
Commercial | Current
Financing Receivable, Past Due [Line Items]
Loans	2,747,384	2,825,126
Commercial | Commercial
Financing Receivable, Past Due [Line Items]
Loans	2,477,077	2,632,290
90 Days Past Due & Accruing	97	176
Commercial | Commercial | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	5,911	5,034
Commercial | Commercial | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	20,492	7,575
Commercial | Commercial | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	26,403	12,609
Commercial | Commercial | Current
Financing Receivable, Past Due [Line Items]
Loans	2,450,674	2,619,681
Commercial | Agricultural
Financing Receivable, Past Due [Line Items]
Loans	296,912	205,623
90 Days Past Due & Accruing	0	0
Commercial | Agricultural | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	76	111
Commercial | Agricultural | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	126	67
Commercial | Agricultural | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	202	178
Commercial | Agricultural | Current
Financing Receivable, Past Due [Line Items]
Loans	296,710	205,445
Other
Financing Receivable, Past Due [Line Items]
Loans	448,309	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	$ 448,306	$ 373,075