Loans and Allowance for Credit Losses - Loan Portfolio by Categories (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
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	355,370	391,224
Consumer | Credit cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	187,052	188,845
Consumer | Other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	168,318	202,379
Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	9,167,250	9,223,791
Real Estate | Construction and development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	1,326,371	1,596,255
Real Estate | Single family residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	2,101,975	1,880,673
Real Estate | Other commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	5,738,904	5,746,863
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	2,160,760	2,750,291
Commercial | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	1,992,043	2,574,386
Commercial | Agricultural
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	168,717	175,905
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	$ 329,123	$ 535,591