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, 2025	Dec. 31, 2024
Financing Receivable, Past Due [Line Items]
Loans	$ 17,094,078	$ 17,005,937
90 Days Past Due & Accruing	494	603
Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	45,889	48,196
90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	106,791	81,698
Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	152,680	129,894
Current
Financing Receivable, Past Due [Line Items]
Loans	16,941,398	16,876,043
Consumer:
Financing Receivable, Past Due [Line Items]
Loans	276,878	308,994
90 Days Past Due & Accruing	459	529
Consumer: | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	2,476	3,576
Consumer: | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	716	1,016
Consumer: | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	3,192	4,592
Consumer: | Current
Financing Receivable, Past Due [Line Items]
Loans	273,686	304,402
Consumer: | Credit cards
Financing Receivable, Past Due [Line Items]
Loans	179,680	181,675
90 Days Past Due & Accruing	459	529
Consumer: | Credit cards | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	1,628	1,824
Consumer: | Credit cards | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	580	635
Consumer: | Credit cards | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	2,208	2,459
Consumer: | Credit cards | Current
Financing Receivable, Past Due [Line Items]
Loans	177,472	179,216
Consumer: | Other consumer
Financing Receivable, Past Due [Line Items]
Loans	97,198	127,319
90 Days Past Due & Accruing	0	0
Consumer: | Other consumer | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	848	1,752
Consumer: | Other consumer | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	136	381
Consumer: | Other consumer | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	984	2,133
Consumer: | Other consumer | Current
Financing Receivable, Past Due [Line Items]
Loans	96,214	125,186
Real Estate:
Financing Receivable, Past Due [Line Items]
Loans	13,477,000	13,391,531
90 Days Past Due & Accruing	8	0
Real Estate: | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	38,732	40,416
Real Estate: | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	78,980	53,516
Real Estate: | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	117,712	93,932
Real Estate: | Current
Financing Receivable, Past Due [Line Items]
Loans	13,359,288	13,297,599
Real Estate: | Construction and development
Financing Receivable, Past Due [Line Items]
Loans	2,778,245	2,789,249
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	426	332
Real Estate: | Construction and development | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	12,933	10,530
Real Estate: | Construction and development | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	13,359	10,862
Real Estate: | Construction and development | Current
Financing Receivable, Past Due [Line Items]
Loans	2,764,886	2,778,387
Real Estate: | Single family residential
Financing Receivable, Past Due [Line Items]
Loans	2,647,451	2,689,946
90 Days Past Due & Accruing	8	0
Real Estate: | Single family residential | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	28,076	34,651
Real Estate: | Single family residential | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	15,531	16,013
Real Estate: | Single family residential | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	43,607	50,664
Real Estate: | Single family residential | Current
Financing Receivable, Past Due [Line Items]
Loans	2,603,844	2,639,282
Real Estate: | Other commercial
Financing Receivable, Past Due [Line Items]
Loans	8,051,304	7,912,336
90 Days Past Due & Accruing	0	0
Real Estate: | Other commercial | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	10,230	5,433
Real Estate: | Other commercial | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	50,516	26,973
Real Estate: | Other commercial | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	60,746	32,406
Real Estate: | Other commercial | Current
Financing Receivable, Past Due [Line Items]
Loans	7,990,558	7,879,930
Commercial
Financing Receivable, Past Due [Line Items]
Loans	2,637,150	2,695,329
90 Days Past Due & Accruing	27	74
Commercial | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	4,681	3,928
Commercial | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	27,092	27,163
Commercial | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	31,773	31,091
Commercial | Current
Financing Receivable, Past Due [Line Items]
Loans	2,605,377	2,664,238
Commercial | Commercial
Financing Receivable, Past Due [Line Items]
Loans	2,372,681	2,434,175
90 Days Past Due & Accruing	27	74
Commercial | Commercial | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	4,496	3,535
Commercial | Commercial | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	26,367	27,059
Commercial | Commercial | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	30,863	30,594
Commercial | Commercial | Current
Financing Receivable, Past Due [Line Items]
Loans	2,341,818	2,403,581
Commercial | Agricultural
Financing Receivable, Past Due [Line Items]
Loans	264,469	261,154
90 Days Past Due & Accruing	0	0
Commercial | Agricultural | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	185	393
Commercial | Agricultural | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	725	104
Commercial | Agricultural | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans	910	497
Commercial | Agricultural | Current
Financing Receivable, Past Due [Line Items]
Loans	263,559	260,657
Other
Financing Receivable, Past Due [Line Items]
Loans	703,050	610,083
90 Days Past Due & Accruing	0	0
Other | Gross 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	0	276
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	279
Other | Current
Financing Receivable, Past Due [Line Items]
Loans	$ 703,047	$ 609,804