Loans and Allowance for Credit Losses - Loans by Credit Risk Rating, Segregated by Class of Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Financing Receivable, Credit Quality Indicator [Line Items]
Total	$ 15,607,135	$ 12,012,503
Loans other than pass or current
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	3,022,119	2,516,672
Fiscal year before current fiscal year	2,514,957	1,525,310
Two years before current fiscal year	1,228,057	709,683
Three years before current fiscal year	622,156	656,367
Four years before current fiscal year	566,287	801,918
Five years before current fiscal year	1,462,385	1,081,384
Lines of Credit (“LOC”) Amortized Cost Basis	6,137,000	4,431,020
LOC Converted to Term Loans Amortized Cost Basis	54,174	290,149
Total	15,607,135	12,012,503
Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Total	373,163	355,370
Consumer | Credit cards
Financing Receivable, Credit Quality Indicator [Line Items]
Total	192,559	187,052
Consumer | Other consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Total	180,604	168,318
Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total	12,089,193	9,167,250
Real Estate | Construction and development
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,372,294	1,326,371
Real Estate | Construction and development | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	184,664	74,813
Fiscal year before current fiscal year	86,225	83,729
Two years before current fiscal year	65,254	28,803
Three years before current fiscal year	20,346	17,349
Four years before current fiscal year	19,807	8,505
Five years before current fiscal year	17,516	9,319
Lines of Credit (“LOC”) Amortized Cost Basis	1,963,664	1,074,617
LOC Converted to Term Loans Amortized Cost Basis	340	20,285
Total	2,357,816	1,317,420
Real Estate | Construction and development | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	252	0
Fiscal year before current fiscal year	0	0
Two years before current fiscal year	0	270
Three years before current fiscal year	0	0
Four years before current fiscal year	0	0
Five years before current fiscal year	42	47
Lines of Credit (“LOC”) Amortized Cost Basis	9,074	0
LOC Converted to Term Loans Amortized Cost Basis	0	0
Total	9,368	317
Real Estate | Construction and development | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	1,005	191
Fiscal year before current fiscal year	85	77
Two years before current fiscal year	10	16
Three years before current fiscal year	14	54
Four years before current fiscal year	31	324
Five years before current fiscal year	138	423
Lines of Credit (“LOC”) Amortized Cost Basis	3,827	5,598
LOC Converted to Term Loans Amortized Cost Basis	0	1,951
Total	5,110	8,634
Real Estate | Construction and development | Doubtful and loss
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
Fiscal year before current fiscal year	0	0
Two years before current fiscal year	0	0
Three years before current fiscal year	0	0
Four years before current fiscal year	0	0
Five years before current fiscal year	0	0
Lines of Credit (“LOC”) Amortized Cost Basis	0	0
LOC Converted to Term Loans Amortized Cost Basis	0	0
Total	0	0
Real Estate | Construction and development | Risk rate 5, 6, and 7
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	185,921	75,004
Fiscal year before current fiscal year	86,310	83,806
Two years before current fiscal year	65,264	29,089
Three years before current fiscal year	20,360	17,403
Four years before current fiscal year	19,838	8,829
Five years before current fiscal year	17,696	9,789
Lines of Credit (“LOC”) Amortized Cost Basis	1,976,565	1,080,215
LOC Converted to Term Loans Amortized Cost Basis	340	22,236
Total	2,372,294	1,326,371
Real Estate | Single family residential
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,467,008	2,101,975
Real Estate | Other commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total	7,249,891	5,738,904
Real Estate | Other commercial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	1,498,718	1,349,746
Fiscal year before current fiscal year	1,544,045	807,701
Two years before current fiscal year	646,921	375,824
Three years before current fiscal year	339,571	267,696
Four years before current fiscal year	241,678	476,029
Five years before current fiscal year	758,803	537,493
Lines of Credit (“LOC”) Amortized Cost Basis	1,882,897	1,409,099
LOC Converted to Term Loans Amortized Cost Basis	19,646	164,856
Total	6,932,279	5,388,444
Real Estate | Other commercial | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	30,970	28,151
Fiscal year before current fiscal year	13,928	30,981
Two years before current fiscal year	31,702	2,799
Three years before current fiscal year	208	6,650
Four years before current fiscal year	6,768	39,361
Five years before current fiscal year	37,207	4,801
Lines of Credit (“LOC”) Amortized Cost Basis	49,083	38,638
LOC Converted to Term Loans Amortized Cost Basis	0	1,608
Total	169,866	152,989
Real Estate | Other commercial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	22,117	28,137
Fiscal year before current fiscal year	16,487	10,186
Two years before current fiscal year	15,292	5,243
Three years before current fiscal year	4,624	10,806
Four years before current fiscal year	8,377	30,060
Five years before current fiscal year	36,445	27,107
Lines of Credit (“LOC”) Amortized Cost Basis	44,404	53,860
LOC Converted to Term Loans Amortized Cost Basis	0	32,072
Total	147,746	197,471
Real Estate | Other commercial | Doubtful and loss
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
Fiscal year before current fiscal year	0	0
Two years before current fiscal year	0	0
Three years before current fiscal year	0	0
Four years before current fiscal year	0	0
Five years before current fiscal year	0	0
Lines of Credit (“LOC”) Amortized Cost Basis	0	0
LOC Converted to Term Loans Amortized Cost Basis	0	0
Total	0	0
Real Estate | Other commercial | Risk rate 5, 6, and 7
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	1,551,805	1,406,034
Fiscal year before current fiscal year	1,574,460	848,868
Two years before current fiscal year	693,915	383,866
Three years before current fiscal year	344,403	285,152
Four years before current fiscal year	256,823	545,450
Five years before current fiscal year	832,455	569,401
Lines of Credit (“LOC”) Amortized Cost Basis	1,976,384	1,501,597
LOC Converted to Term Loans Amortized Cost Basis	19,646	198,536
Total	7,249,891	5,738,904
Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,788,757	2,160,760
Commercial | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,525,218	1,992,043
Commercial | Commercial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	503,656	455,499
Fiscal year before current fiscal year	330,386	187,517
Two years before current fiscal year	167,711	80,486
Three years before current fiscal year	75,215	57,437
Four years before current fiscal year	43,335	36,529
Five years before current fiscal year	54,340	57,099
Lines of Credit (“LOC”) Amortized Cost Basis	1,281,039	1,004,971
LOC Converted to Term Loans Amortized Cost Basis	27,220	41,885
Total	2,482,902	1,921,423
Commercial | Commercial | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	51	670
Fiscal year before current fiscal year	1,080	2,482
Two years before current fiscal year	34	1,066
Three years before current fiscal year	58	189
Four years before current fiscal year	8	261
Five years before current fiscal year	963	2,770
Lines of Credit (“LOC”) Amortized Cost Basis	2,042	8,500
LOC Converted to Term Loans Amortized Cost Basis	0	10,499
Total	4,236	26,437
Commercial | Commercial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	2,247	3,436
Fiscal year before current fiscal year	6,059	18,381
Two years before current fiscal year	764	4,397
Three years before current fiscal year	1,014	1,196
Four years before current fiscal year	1,462	578
Five years before current fiscal year	4,682	850
Lines of Credit (“LOC”) Amortized Cost Basis	20,968	8,242
LOC Converted to Term Loans Amortized Cost Basis	884	7,103
Total	38,080	44,183
Commercial | Commercial | Doubtful and loss
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
Fiscal year before current fiscal year	0	0
Two years before current fiscal year	0	0
Three years before current fiscal year	0	0
Four years before current fiscal year	0	0
Five years before current fiscal year	0	0
Lines of Credit (“LOC”) Amortized Cost Basis	0	0
LOC Converted to Term Loans Amortized Cost Basis	0	0
Total	0	0
Commercial | Commercial | Risk rate 5, 6, and 7
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	505,954	459,605
Fiscal year before current fiscal year	337,525	208,380
Two years before current fiscal year	168,509	85,949
Three years before current fiscal year	76,287	58,822
Four years before current fiscal year	44,805	37,368
Five years before current fiscal year	59,985	60,719
Lines of Credit (“LOC”) Amortized Cost Basis	1,304,049	1,021,713
LOC Converted to Term Loans Amortized Cost Basis	28,104	59,487
Total	2,525,218	1,992,043
Commercial | Agricultural
Financing Receivable, Credit Quality Indicator [Line Items]
Total	263,539	168,717
Commercial | Agricultural | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	34,791	32,780
Fiscal year before current fiscal year	25,667	20,230
Two years before current fiscal year	12,321	10,253
Three years before current fiscal year	6,336	3,646
Four years before current fiscal year	1,600	2,364
Five years before current fiscal year	1,469	459
Lines of Credit (“LOC”) Amortized Cost Basis	180,276	98,245
LOC Converted to Term Loans Amortized Cost Basis	413	327
Total	262,873	168,304
Commercial | Agricultural | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
Fiscal year before current fiscal year	0	0
Two years before current fiscal year	0	0
Three years before current fiscal year	0	0
Four years before current fiscal year	0	0
Five years before current fiscal year	0	0
Lines of Credit (“LOC”) Amortized Cost Basis	0	0
LOC Converted to Term Loans Amortized Cost Basis	0	0
Total	0	0
Commercial | Agricultural | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	9	191
Fiscal year before current fiscal year	23	25
Two years before current fiscal year	5	27
Three years before current fiscal year	57	53
Four years before current fiscal year	10	22
Five years before current fiscal year	0	3
Lines of Credit (“LOC”) Amortized Cost Basis	562	23
LOC Converted to Term Loans Amortized Cost Basis	0	69
Total	666	413
Commercial | Agricultural | Doubtful and loss
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
Fiscal year before current fiscal year	0	0
Two years before current fiscal year	0	0
Three years before current fiscal year	0	0
Four years before current fiscal year	0	0
Five years before current fiscal year	0	0
Lines of Credit (“LOC”) Amortized Cost Basis	0	0
LOC Converted to Term Loans Amortized Cost Basis	0	0
Total	0	0
Commercial | Agricultural | Risk rate 5, 6, and 7
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	34,800	32,971
Fiscal year before current fiscal year	25,690	20,255
Two years before current fiscal year	12,326	10,280
Three years before current fiscal year	6,393	3,699
Four years before current fiscal year	1,610	2,386
Five years before current fiscal year	1,469	462
Lines of Credit (“LOC”) Amortized Cost Basis	180,838	98,268
LOC Converted to Term Loans Amortized Cost Basis	413	396
Total	263,539	168,717
Other
Financing Receivable, Credit Quality Indicator [Line Items]
Total	356,022	329,123
Current
Financing Receivable, Credit Quality Indicator [Line Items]
Total	15,553,709	11,958,874
Current | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Total	370,615	352,831
Current | Consumer | Credit cards
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
Fiscal year before current fiscal year	0	0
Two years before current fiscal year	0	0
Three years before current fiscal year	0	0
Four years before current fiscal year	0	0
Five years before current fiscal year	0	0
Lines of Credit (“LOC”) Amortized Cost Basis	190,944	185,792
LOC Converted to Term Loans Amortized Cost Basis	0	0
Total	190,944	185,792
Current | Consumer | Other consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	101,692	97,830
Fiscal year before current fiscal year	31,531	21,885
Two years before current fiscal year	12,111	11,712
Three years before current fiscal year	5,375	6,756
Four years before current fiscal year	3,465	5,416
Five years before current fiscal year	3,514	3,833
Lines of Credit (“LOC”) Amortized Cost Basis	21,980	19,607
LOC Converted to Term Loans Amortized Cost Basis	3	0
Total	179,671	167,039
Current | Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total	12,049,881	9,131,179
Current | Real Estate | Construction and development
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,369,050	1,325,753
Current | Real Estate | Single family residential
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	544,782	419,605
Fiscal year before current fiscal year	426,319	335,788
Two years before current fiscal year	265,458	185,190
Three years before current fiscal year	162,395	260,037
Four years before current fiscal year	216,192	193,110
Five years before current fiscal year	509,819	421,957
Lines of Credit (“LOC”) Amortized Cost Basis	314,903	256,155
LOC Converted to Term Loans Amortized Cost Basis	4,715	9,422
Total	2,444,583	2,081,264
Current | Real Estate | Other commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total	7,236,248	5,724,162
Current | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,777,194	2,145,744
Current | Commercial | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,513,736	1,977,157
Current | Commercial | Agricultural
Financing Receivable, Credit Quality Indicator [Line Items]
Total	263,458	168,587
Current | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	96,254	24,247
Fiscal year before current fiscal year	30,852	4,740
Two years before current fiscal year	8,599	1,236
Three years before current fiscal year	5,529	22,438
Four years before current fiscal year	20,537	6,692
Five years before current fiscal year	26,057	5,578
Lines of Credit (“LOC”) Amortized Cost Basis	167,238	264,189
LOC Converted to Term Loans Amortized Cost Basis	953	0
Total	356,019	329,120
30-89 days past due | Consumer | Credit cards
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
Fiscal year before current fiscal year	0	0
Two years before current fiscal year	0	0
Three years before current fiscal year	0	0
Four years before current fiscal year	0	0
Five years before current fiscal year	0	0
Lines of Credit (“LOC”) Amortized Cost Basis	1,348	847
LOC Converted to Term Loans Amortized Cost Basis	0	0
Total	1,348	847
30-89 days past due | Consumer | Other consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	279	265
Fiscal year before current fiscal year	270	121
Two years before current fiscal year	68	164
Three years before current fiscal year	46	49
Four years before current fiscal year	17	219
Five years before current fiscal year	128	156
Lines of Credit (“LOC”) Amortized Cost Basis	6	175
LOC Converted to Term Loans Amortized Cost Basis	0	0
Total	814	1,149
30-89 days past due | Real Estate | Single family residential
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	453	1,061
Fiscal year before current fiscal year	1,070	883
Two years before current fiscal year	1,222	1,662
Three years before current fiscal year	420	791
Four years before current fiscal year	1,786	1,077
Five years before current fiscal year	5,435	4,360
Lines of Credit (“LOC”) Amortized Cost Basis	789	1,479
LOC Converted to Term Loans Amortized Cost Basis	0	0
Total	11,175	11,313
30-89 days past due | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
Fiscal year before current fiscal year	0	0
Two years before current fiscal year	0	0
Three years before current fiscal year	0	0
Four years before current fiscal year	0	0
Five years before current fiscal year	0	0
Lines of Credit (“LOC”) Amortized Cost Basis	0	0
LOC Converted to Term Loans Amortized Cost Basis	0	0
Total	0	0
90+ days past due
Financing Receivable, Credit Quality Indicator [Line Items]
Total	28,486	32,907
90+ days past due | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Total	386	543
90+ days past due | Consumer | Credit cards
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
Fiscal year before current fiscal year	0	0
Two years before current fiscal year	0	0
Three years before current fiscal year	0	0
Four years before current fiscal year	0	0
Five years before current fiscal year	0	0
Lines of Credit (“LOC”) Amortized Cost Basis	267	413
LOC Converted to Term Loans Amortized Cost Basis	0	0
Total	267	413
90+ days past due | Consumer | Other consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	19	23
Fiscal year before current fiscal year	26	23
Two years before current fiscal year	20	28
Three years before current fiscal year	12	21
Four years before current fiscal year	2	13
Five years before current fiscal year	31	22
Lines of Credit (“LOC”) Amortized Cost Basis	9	0
LOC Converted to Term Loans Amortized Cost Basis	0	0
Total	119	130
90+ days past due | Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total	21,063	22,170
90+ days past due | Real Estate | Construction and development
Financing Receivable, Credit Quality Indicator [Line Items]
Total	1,631	504
90+ days past due | Real Estate | Single family residential
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	160	27
Fiscal year before current fiscal year	904	561
Two years before current fiscal year	565	507
Three years before current fiscal year	936	1,199
Four years before current fiscal year	1,212	1,358
Five years before current fiscal year	5,793	5,104
Lines of Credit (“LOC”) Amortized Cost Basis	1,680	570
LOC Converted to Term Loans Amortized Cost Basis	0	72
Total	11,250	9,398
90+ days past due | Real Estate | Other commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total	8,182	12,268
90+ days past due | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total	7,034	10,191
90+ days past due | Commercial | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total	7,008	10,074
90+ days past due | Commercial | Agricultural
Financing Receivable, Credit Quality Indicator [Line Items]
Total	26	117
90+ days past due | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
Fiscal year before current fiscal year	0	0
Two years before current fiscal year	0	0
Three years before current fiscal year	0	0
Four years before current fiscal year	0	0
Five years before current fiscal year	3	3
Lines of Credit (“LOC”) Amortized Cost Basis	0	0
LOC Converted to Term Loans Amortized Cost Basis	0	0
Total	3	3
30 + days past due | Consumer | Credit cards
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
Fiscal year before current fiscal year	0	0
Two years before current fiscal year	0	0
Three years before current fiscal year	0	0
Four years before current fiscal year	0	0
Five years before current fiscal year	0	0
Lines of Credit (“LOC”) Amortized Cost Basis	192,559	187,052
LOC Converted to Term Loans Amortized Cost Basis	0	0
Total	192,559	187,052
30 + days past due | Consumer | Other consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	101,990	98,118
Fiscal year before current fiscal year	31,827	22,029
Two years before current fiscal year	12,199	11,904
Three years before current fiscal year	5,433	6,826
Four years before current fiscal year	3,484	5,648
Five years before current fiscal year	3,673	4,011
Lines of Credit (“LOC”) Amortized Cost Basis	21,995	19,782
LOC Converted to Term Loans Amortized Cost Basis	3	0
Total	180,604	168,318
30 + days past due | Real Estate | Single family residential
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	545,395	420,693
Fiscal year before current fiscal year	428,293	337,232
Two years before current fiscal year	267,245	187,359
Three years before current fiscal year	163,751	262,027
Four years before current fiscal year	219,190	195,545
Five years before current fiscal year	521,047	431,421
Lines of Credit (“LOC”) Amortized Cost Basis	317,372	258,204
LOC Converted to Term Loans Amortized Cost Basis	4,715	9,494
Total	2,467,008	2,101,975
30 + days past due | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	96,254	24,247
Fiscal year before current fiscal year	30,852	4,740
Two years before current fiscal year	8,599	1,236
Three years before current fiscal year	5,529	22,438
Four years before current fiscal year	20,537	6,692
Five years before current fiscal year	26,060	5,581
Lines of Credit (“LOC”) Amortized Cost Basis	167,238	264,189
LOC Converted to Term Loans Amortized Cost Basis	953	0
Total	$ 356,022	$ 329,123