Loans and Allowance for Credit Losses - Loan Portfolio by Categories (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Loans and Leases Receivable Disclosure [Line Items]
Loans	$ 12,028,593	$ 12,012,503
Consumer
Loans and Leases Receivable Disclosure [Line Items]
Loans	364,974	355,370
Consumer | Credit cards
Loans and Leases Receivable Disclosure [Line Items]
Loans	184,372	187,052
Consumer | Other consumer
Loans and Leases Receivable Disclosure [Line Items]
Loans	180,602	168,318
Real Estate
Loans and Leases Receivable Disclosure [Line Items]
Loans	9,228,990	9,167,250
Real Estate | Construction and development
Loans and Leases Receivable Disclosure [Line Items]
Loans	1,423,445	1,326,371
Real Estate | Single family residential
Loans and Leases Receivable Disclosure [Line Items]
Loans	2,042,978	2,101,975
Real Estate | Other commercial
Loans and Leases Receivable Disclosure [Line Items]
Loans	5,762,567	5,738,904
Commercial
Loans and Leases Receivable Disclosure [Line Items]
Loans	2,166,870	2,160,760
Commercial | Commercial
Loans and Leases Receivable Disclosure [Line Items]
Loans	2,016,405	1,992,043
Commercial | Agricultural
Loans and Leases Receivable Disclosure [Line Items]
Loans	150,465	168,717
Other
Loans and Leases Receivable Disclosure [Line Items]
Loans	$ 267,759	$ 329,123