v3.26.3
Fair Value Disclosures - Summary of the Carrying Amounts and Estimated Fair Values of Financial Instruments (Details) - USD ($)
$ in Thousands
Sep. 30, 2026
Dec. 31, 2025
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available-for-sale debt securities $ 4,095,855 $ 3,951,455
Held-to-maturity debt securities 672,881 725,722
Equity securities 42,007 41,998
Trading debt securities 0 3,924
Derivative assets 14,461 40,892
Long-term debt 487,270 620,575
Derivative liabilities 140,096 24,458
Carrying Amount    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Cash and cash equivalents 2,674,159 2,099,118
Available-for-sale debt securities 4,095,855 3,951,455
Held-to-maturity debt securities 672,881 725,722
Equity securities 42,007 41,998
Trading debt securities   3,924
Loans held for sale 28,676 4,361
Loans held for investment, net 23,812,657 23,769,645
Derivative assets 14,461 40,892
Other trading assets 40  
Total deposits 27,715,655 26,448,767
Short-term borrowings   330,000
Long-term debt 487,270 620,575
Securities sold not yet purchased 12,297 12,026
Derivative liabilities 140,096 24,458
Estimated Fair Value    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Cash and cash equivalents 2,674,159 2,099,118
Available-for-sale debt securities 4,095,855 3,951,455
Held-to-maturity debt securities 575,384 654,832
Equity securities 42,007 41,998
Trading debt securities   3,924
Loans held for sale 28,813 4,361
Loans held for investment, net 23,536,212 23,604,206
Derivative assets 14,461 40,892
Other trading assets 40  
Total deposits 27,788,533 26,450,932
Short-term borrowings   330,000
Long-term debt 470,958 593,610
Securities sold not yet purchased 12,297 12,026
Derivative liabilities 140,096 24,458
Level 1    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Equity securities 32,007 31,998
Trading debt securities   0
Loans held for investment, net 0 0
Derivative assets 0 0
Other trading assets 40  
Securities sold not yet purchased 12,297 12,026
Derivative liabilities 0 0
Level 1 | Estimated Fair Value    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Cash and cash equivalents 2,674,159 2,099,118
Available-for-sale debt securities 0 0
Held-to-maturity debt securities 0 0
Equity securities 32,007 31,998
Trading debt securities   0
Loans held for sale 0
Loans held for investment, net 0 0
Derivative assets 0 0
Other trading assets 40  
Total deposits 0 0
Short-term borrowings   0
Long-term debt 0 0
Securities sold not yet purchased 12,297 12,026
Derivative liabilities 0 0
Level 2    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Equity securities 10,000 10,000
Trading debt securities   3,924
Loans held for investment, net 0 0
Derivative assets 14,461 40,892
Other trading assets 0  
Securities sold not yet purchased 0 0
Derivative liabilities 140,096 24,458
Level 2 | Estimated Fair Value    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Cash and cash equivalents 0 0
Available-for-sale debt securities 4,085,736 3,940,658
Held-to-maturity debt securities 575,384 654,832
Equity securities 10,000 10,000
Trading debt securities   3,924
Loans held for sale 28,813 4,361
Loans held for investment, net 0 0
Derivative assets 14,461 40,892
Other trading assets 0  
Total deposits 0 0
Short-term borrowings   330,000
Long-term debt 470,958 593,610
Securities sold not yet purchased 0 0
Derivative liabilities 140,096 24,458
Level 3    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Equity securities 0 0
Trading debt securities   0
Loans held for investment, net 26,865 20,844
Derivative assets 0 0
Other trading assets 0  
Securities sold not yet purchased 0 0
Derivative liabilities 0 0
Level 3 | Estimated Fair Value    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Cash and cash equivalents 0 0
Available-for-sale debt securities 10,119 10,797
Held-to-maturity debt securities 0 0
Equity securities 0 0
Trading debt securities   0
Loans held for sale 0
Loans held for investment, net 23,536,212 23,604,206
Derivative assets 0 0
Other trading assets 0  
Total deposits 27,788,533 26,450,932
Short-term borrowings   0
Long-term debt 0 0
Securities sold not yet purchased 0 0
Derivative liabilities $ 0 $ 0