Loans and Allowance for Credit Losses - Age Analysis of Past Due Loans, Excluding Loans Acquired, Segregated by Class of Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	$ 12,012,503	$ 12,900,897
90 Days Past Due & Accruing	349	578
Gross 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	20,722	39,072
90 Days or More Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	32,907	35,188
Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	53,629	74,260
Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	11,958,874	12,826,637
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	355,370	391,224
90 Days Past Due & Accruing	247	269
Consumer | Gross 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	1,996	3,479
Consumer | 90 Days or More Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	543	558
Consumer | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	2,539	4,037
Consumer | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	352,831	387,187
Consumer | Credit cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	187,052	188,845
90 Days Past Due & Accruing	247	256
Consumer | Credit cards | Gross 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	847	708
Consumer | Credit cards | 90 Days or More Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	413	256
Consumer | Credit cards | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	1,260	964
Consumer | Credit cards | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	185,792	187,881
Consumer | Other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	168,318	202,379
90 Days Past Due & Accruing	0	13
Consumer | Other consumer | Gross 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	1,149	2,771
Consumer | Other consumer | 90 Days or More Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	130	302
Consumer | Other consumer | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	1,279	3,073
Consumer | Other consumer | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	167,039	199,306
Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	9,167,250	9,223,791
90 Days Past Due & Accruing	102	253
Real Estate | Gross 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	13,901	27,761
Real Estate | 90 Days or More Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	22,170	27,014
Real Estate | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	36,071	54,775
Real Estate | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	9,131,179	9,169,016
Real Estate | Construction and development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	1,326,371	1,596,255
90 Days Past Due & Accruing	0	0
Real Estate | Construction and development | Gross 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	114	1,375
Real Estate | Construction and development | 90 Days or More Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	504	3,089
Real Estate | Construction and development | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	618	4,464
Real Estate | Construction and development | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	1,325,753	1,591,791
Real Estate | Single family residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	2,101,975	1,880,673
90 Days Past Due & Accruing	102	253
Real Estate | Single family residential | Gross 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	11,313	23,726
Real Estate | Single family residential | 90 Days or More Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	9,398	14,339
Real Estate | Single family residential | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	20,711	38,065
Real Estate | Single family residential | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	2,081,264	1,842,608
Real Estate | Other commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	5,738,904	5,746,863
90 Days Past Due & Accruing	0	0
Real Estate | Other commercial | Gross 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	2,474	2,660
Real Estate | Other commercial | 90 Days or More Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	12,268	9,586
Real Estate | Other commercial | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	14,742	12,246
Real Estate | Other commercial | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	5,724,162	5,734,617
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	2,160,760	2,750,291
90 Days Past Due & Accruing	0	56
Commercial | Gross 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	4,825	7,740
Commercial | 90 Days or More Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	10,191	7,616
Commercial | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	15,016	15,356
Commercial | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	2,145,744	2,734,935
Commercial | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	1,992,043	2,574,386
90 Days Past Due & Accruing	0	56
Commercial | Commercial | Gross 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	4,812	7,514
Commercial | Commercial | 90 Days or More Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	10,074	7,429
Commercial | Commercial | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	14,886	14,943
Commercial | Commercial | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	1,977,157	2,559,443
Commercial | Agricultural
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	168,717	175,905
90 Days Past Due & Accruing	0	0
Commercial | Agricultural | Gross 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	13	226
Commercial | Agricultural | 90 Days or More Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	117	187
Commercial | Agricultural | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	130	413
Commercial | Agricultural | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	168,587	175,492
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	329,123	535,591
90 Days Past Due & Accruing	0	0
Other | Gross 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	0	92
Other | 90 Days or More Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	3	0
Other | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	3	92
Other | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	$ 329,120	$ 535,499