Loans and Allowance for Credit Losses - Loans by Credit Risk Rating, Segregated by Class of Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Financing Receivable, Credit Quality Indicator [Line Items]
Total	$ 12,028,593	$ 12,012,503
Loans other than pass or current
Financing Receivable, Credit Quality Indicator [Line Items]
2022 (YTD)	948,554	2,516,672
2021	2,682,134	1,525,310
2020	1,689,421	709,683
2019	556,351	656,367
2018	488,061	801,918
2017 and Prior	1,263,445	1,081,384
Lines of Credit (“LOC”) Amortized Cost Basis	4,371,014	4,431,020
LOC Converted to Term Loans Amortized Cost Basis	29,613	290,149
Total	12,028,593	12,012,503
Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Total	364,974	355,370
Consumer | Credit cards
Financing Receivable, Credit Quality Indicator [Line Items]
Total	184,372	187,052
Consumer | Other consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Total	180,602	168,318
Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total	9,228,990	9,167,250
Real Estate | Construction and development
Financing Receivable, Credit Quality Indicator [Line Items]
Total	1,423,445	1,326,371
Real Estate | Construction and development | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2022 (YTD)	36,921	74,813
2021	83,202	83,729
2020	84,969	28,803
2019	21,988	17,349
2018	12,221	8,505
2017 and Prior	10,831	9,319
Lines of Credit (“LOC”) Amortized Cost Basis	1,166,464	1,074,617
LOC Converted to Term Loans Amortized Cost Basis	3,694	20,285
Total	1,420,290	1,317,420
Real Estate | Construction and development | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
2022 (YTD)	0	0
2021	0	0
2020	0	270
2019	265	0
2018	0	0
2017 and Prior	46	47
Lines of Credit (“LOC”) Amortized Cost Basis	0	0
LOC Converted to Term Loans Amortized Cost Basis	0	0
Total	311	317
Real Estate | Construction and development | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2022 (YTD)	1,066	191
2021	184	77
2020	52	16
2019	15	54
2018	35	324
2017 and Prior	123	423
Lines of Credit (“LOC”) Amortized Cost Basis	1,369	5,598
LOC Converted to Term Loans Amortized Cost Basis	0	1,951
Total	2,844	8,634
Real Estate | Construction and development | Doubtful and loss
Financing Receivable, Credit Quality Indicator [Line Items]
2022 (YTD)	0	0
2021	0	0
2020	0	0
2019	0	0
2018	0	0
2017 and Prior	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]
2022 (YTD)	37,987	75,004
2021	83,386	83,806
2020	85,021	29,089
2019	22,268	17,403
2018	12,256	8,829
2017 and Prior	11,000	9,789
Lines of Credit (“LOC”) Amortized Cost Basis	1,167,833	1,080,215
LOC Converted to Term Loans Amortized Cost Basis	3,694	22,236
Total	1,423,445	1,326,371
Real Estate | Single family residential
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,042,978	2,101,975
Real Estate | Other commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total	5,762,567	5,738,904
Real Estate | Other commercial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2022 (YTD)	512,084	1,349,746
2021	1,559,457	807,701
2020	917,510	375,824
2019	295,515	267,696
2018	176,517	476,029
2017 and Prior	579,079	537,493
Lines of Credit (“LOC”) Amortized Cost Basis	1,317,696	1,409,099
LOC Converted to Term Loans Amortized Cost Basis	19,730	164,856
Total	5,377,588	5,388,444
Real Estate | Other commercial | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
2022 (YTD)	31,411	28,151
2021	11,572	30,981
2020	51,706	2,799
2019	1,241	6,650
2018	1,635	39,361
2017 and Prior	9,511	4,801
Lines of Credit (“LOC”) Amortized Cost Basis	65,879	38,638
LOC Converted to Term Loans Amortized Cost Basis	0	1,608
Total	172,955	152,989
Real Estate | Other commercial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2022 (YTD)	4,895	28,137
2021	67,793	10,186
2020	49,225	5,243
2019	3,416	10,806
2018	3,000	30,060
2017 and Prior	30,247	27,107
Lines of Credit (“LOC”) Amortized Cost Basis	53,448	53,860
LOC Converted to Term Loans Amortized Cost Basis	0	32,072
Total	212,024	197,471
Real Estate | Other commercial | Doubtful and loss
Financing Receivable, Credit Quality Indicator [Line Items]
2022 (YTD)	0	0
2021	0	0
2020	0	0
2019	0	0
2018	0	0
2017 and Prior	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]
2022 (YTD)	548,390	1,406,034
2021	1,638,822	848,868
2020	1,018,441	383,866
2019	300,172	285,152
2018	181,152	545,450
2017 and Prior	618,837	569,401
Lines of Credit (“LOC”) Amortized Cost Basis	1,437,023	1,501,597
LOC Converted to Term Loans Amortized Cost Basis	19,730	198,536
Total	5,762,567	5,738,904
Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,166,870	2,160,760
Commercial | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,016,405	1,992,043
Commercial | Commercial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2022 (YTD)	171,244	455,499
2021	416,875	187,517
2020	204,615	80,486
2019	57,498	57,437
2018	43,756	36,529
2017 and Prior	75,701	57,099
Lines of Credit (“LOC”) Amortized Cost Basis	1,002,977	1,004,971
LOC Converted to Term Loans Amortized Cost Basis	2,848	41,885
Total	1,975,514	1,921,423
Commercial | Commercial | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
2022 (YTD)	3,718	670
2021	1,373	2,482
2020	1,808	1,066
2019	112	189
2018	12	261
2017 and Prior	1,038	2,770
Lines of Credit (“LOC”) Amortized Cost Basis	3,803	8,500
LOC Converted to Term Loans Amortized Cost Basis	0	10,499
Total	11,864	26,437
Commercial | Commercial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2022 (YTD)	451	3,436
2021	6,913	18,381
2020	4,337	4,397
2019	1,540	1,196
2018	1,083	578
2017 and Prior	2,899	850
Lines of Credit (“LOC”) Amortized Cost Basis	11,603	8,242
LOC Converted to Term Loans Amortized Cost Basis	201	7,103
Total	29,027	44,183
Commercial | Commercial | Doubtful and loss
Financing Receivable, Credit Quality Indicator [Line Items]
2022 (YTD)	0	0
2021	0	0
2020	0	0
2019	0	0
2018	0	0
2017 and Prior	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]
2022 (YTD)	175,413	459,605
2021	425,161	208,380
2020	210,760	85,949
2019	59,150	58,822
2018	44,851	37,368
2017 and Prior	79,638	60,719
Lines of Credit (“LOC”) Amortized Cost Basis	1,018,383	1,021,713
LOC Converted to Term Loans Amortized Cost Basis	3,049	59,487
Total	2,016,405	1,992,043
Commercial | Agricultural
Financing Receivable, Credit Quality Indicator [Line Items]
Total	150,465	168,717
Commercial | Agricultural | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2022 (YTD)	12,418	32,780
2021	31,654	20,230
2020	16,797	10,253
2019	7,300	3,646
2018	2,234	2,364
2017 and Prior	1,987	459
Lines of Credit (“LOC”) Amortized Cost Basis	76,716	98,245
LOC Converted to Term Loans Amortized Cost Basis	1,059	327
Total	150,165	168,304
Commercial | Agricultural | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
2022 (YTD)	0	0
2021	0	0
2020	0	0
2019	0	0
2018	0	0
2017 and Prior	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]
2022 (YTD)	0	191
2021	79	25
2020	0	27
2019	68	53
2018	39	22
2017 and Prior	1	3
Lines of Credit (“LOC”) Amortized Cost Basis	113	23
LOC Converted to Term Loans Amortized Cost Basis	0	69
Total	300	413
Commercial | Agricultural | Doubtful and loss
Financing Receivable, Credit Quality Indicator [Line Items]
2022 (YTD)	0	0
2021	0	0
2020	0	0
2019	0	0
2018	0	0
2017 and Prior	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]
2022 (YTD)	12,418	32,971
2021	31,733	20,255
2020	16,797	10,280
2019	7,368	3,699
2018	2,273	2,386
2017 and Prior	1,988	462
Lines of Credit (“LOC”) Amortized Cost Basis	76,829	98,268
LOC Converted to Term Loans Amortized Cost Basis	1,059	396
Total	150,465	168,717
Other
Financing Receivable, Credit Quality Indicator [Line Items]
Total	267,759	329,123
Current
Financing Receivable, Credit Quality Indicator [Line Items]
Total	11,968,315	11,958,874
Current | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Total	362,597	352,831
Current | Consumer | Credit cards
Financing Receivable, Credit Quality Indicator [Line Items]
2022 (YTD)	0	0
2021	0	0
2020	0	0
2019	0	0
2018	0	0
2017 and Prior	0	0
Lines of Credit (“LOC”) Amortized Cost Basis	183,170	185,792
LOC Converted to Term Loans Amortized Cost Basis	0	0
Total	183,170	185,792
Current | Consumer | Other consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2022 (YTD)	79,761	97,830
2021	43,528	21,885
2020	18,213	11,712
2019	8,773	6,756
2018	5,164	5,416
2017 and Prior	6,467	3,833
Lines of Credit (“LOC”) Amortized Cost Basis	17,517	19,607
LOC Converted to Term Loans Amortized Cost Basis	4	0
Total	179,427	167,039
Current | Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total	9,184,207	9,131,179
Current | Real Estate | Construction and development
Financing Receivable, Credit Quality Indicator [Line Items]
Total	1,422,901	1,325,753
Current | Real Estate | Single family residential
Financing Receivable, Credit Quality Indicator [Line Items]
2022 (YTD)	94,349	419,605
2021	432,131	335,788
2020	331,902	185,190
2019	154,549	260,037
2018	217,889	193,110
2017 and Prior	519,907	421,957
Lines of Credit (“LOC”) Amortized Cost Basis	263,355	256,155
LOC Converted to Term Loans Amortized Cost Basis	2,077	9,422
Total	2,016,159	2,081,264
Current | Real Estate | Other commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total	5,745,147	5,724,162
Current | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,153,772	2,145,744
Current | Commercial | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,003,616	1,977,157
Current | Commercial | Agricultural
Financing Receivable, Credit Quality Indicator [Line Items]
Total	150,156	168,587
Current | Other
Financing Receivable, Credit Quality Indicator [Line Items]
2022 (YTD)	28	24,247
2021	24,198	4,740
2020	4,616	1,236
2019	1,170	22,438
2018	22,241	6,692
2017 and Prior	11,612	5,578
Lines of Credit (“LOC”) Amortized Cost Basis	203,874	264,189
LOC Converted to Term Loans Amortized Cost Basis	0	0
Total	267,739	329,120
30-89 days past due | Consumer | Credit cards
Financing Receivable, Credit Quality Indicator [Line Items]
2022 (YTD)	0	0
2021	0	0
2020	0	0
2019	0	0
2018	0	0
2017 and Prior	0	0
Lines of Credit (“LOC”) Amortized Cost Basis	840	847
LOC Converted to Term Loans Amortized Cost Basis	0	0
Total	840	847
30-89 days past due | Consumer | Other consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2022 (YTD)	15	265
2021	476	121
2020	122	164
2019	90	49
2018	83	219
2017 and Prior	245	156
Lines of Credit (“LOC”) Amortized Cost Basis	52	175
LOC Converted to Term Loans Amortized Cost Basis	0	0
Total	1,083	1,149
30-89 days past due | Real Estate | Single family residential
Financing Receivable, Credit Quality Indicator [Line Items]
2022 (YTD)	52	1,061
2021	2,445	883
2020	3,040	1,662
2019	2,010	791
2018	1,348	1,077
2017 and Prior	8,189	4,360
Lines of Credit (“LOC”) Amortized Cost Basis	1,189	1,479
LOC Converted to Term Loans Amortized Cost Basis	0	0
Total	18,273	11,313
30-89 days past due | Other
Financing Receivable, Credit Quality Indicator [Line Items]
2022 (YTD)	0	0
2021	0	0
2020	0	0
2019	17	0
2018	0	0
2017 and Prior	0	0
Lines of Credit (“LOC”) Amortized Cost Basis	0	0
LOC Converted to Term Loans Amortized Cost Basis	0	0
Total	17	0
90+ days past due
Financing Receivable, Credit Quality Indicator [Line Items]
Total	29,145	32,907
90+ days past due | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Total	454	543
90+ days past due | Consumer | Credit cards
Financing Receivable, Credit Quality Indicator [Line Items]
2022 (YTD)	0	0
2021	0	0
2020	0	0
2019	0	0
2018	0	0
2017 and Prior	0	0
Lines of Credit (“LOC”) Amortized Cost Basis	362	413
LOC Converted to Term Loans Amortized Cost Basis	0	0
Total	362	413
90+ days past due | Consumer | Other consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2022 (YTD)	0	23
2021	31	23
2020	7	28
2019	9	21
2018	3	13
2017 and Prior	42	22
Lines of Credit (“LOC”) Amortized Cost Basis	0	0
LOC Converted to Term Loans Amortized Cost Basis	0	0
Total	92	130
90+ days past due | Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total	20,407	22,170
90+ days past due | Real Estate | Construction and development
Financing Receivable, Credit Quality Indicator [Line Items]
Total	118	504
90+ days past due | Real Estate | Single family residential
Financing Receivable, Credit Quality Indicator [Line Items]
2022 (YTD)	141	27
2021	223	561
2020	502	507
2019	775	1,199
2018	801	1,358
2017 and Prior	5,517	5,104
Lines of Credit (“LOC”) Amortized Cost Basis	587	570
LOC Converted to Term Loans Amortized Cost Basis	0	72
Total	8,546	9,398
90+ days past due | Real Estate | Other commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total	11,743	12,268
90+ days past due | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total	8,281	10,191
90+ days past due | Commercial | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total	8,082	10,074
90+ days past due | Commercial | Agricultural
Financing Receivable, Credit Quality Indicator [Line Items]
Total	199	117
90+ days past due | Other
Financing Receivable, Credit Quality Indicator [Line Items]
2022 (YTD)	0	0
2021	0	0
2020	0	0
2019	0	0
2018	0	0
2017 and Prior	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]
2022 (YTD)	0	0
2021	0	0
2020	0	0
2019	0	0
2018	0	0
2017 and Prior	0	0
Lines of Credit (“LOC”) Amortized Cost Basis	184,372	187,052
LOC Converted to Term Loans Amortized Cost Basis	0	0
Total	184,372	187,052
30 + days past due | Consumer | Other consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2022 (YTD)	79,776	98,118
2021	44,035	22,029
2020	18,342	11,904
2019	8,872	6,826
2018	5,250	5,648
2017 and Prior	6,754	4,011
Lines of Credit (“LOC”) Amortized Cost Basis	17,569	19,782
LOC Converted to Term Loans Amortized Cost Basis	4	0
Total	180,602	168,318
30 + days past due | Real Estate | Single family residential
Financing Receivable, Credit Quality Indicator [Line Items]
2022 (YTD)	94,542	420,693
2021	434,799	337,232
2020	335,444	187,359
2019	157,334	262,027
2018	220,038	195,545
2017 and Prior	533,613	431,421
Lines of Credit (“LOC”) Amortized Cost Basis	265,131	258,204
LOC Converted to Term Loans Amortized Cost Basis	2,077	9,494
Total	2,042,978	2,101,975
30 + days past due | Other
Financing Receivable, Credit Quality Indicator [Line Items]
2022 (YTD)	28	24,247
2021	24,198	4,740
2020	4,616	1,236
2019	1,187	22,438
2018	22,241	6,692
2017 and Prior	11,615	5,581
Lines of Credit (“LOC”) Amortized Cost Basis	203,874	264,189
LOC Converted to Term Loans Amortized Cost Basis	0	0
Total	$ 267,759	$ 329,123