v3.26.1
Loans and Allowance for Credit Losses - Additional Information (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Dec. 31, 2025
Dec. 31, 2024
Accounts Notes And Loans Receivable [Line Items]            
Percentage of Loans Related to Single Industry on Loans 10.00%   10.00%   10.00%  
Percentage of real estate loans aggregating to company loan portfolio, excluding Warehouse Purchase Program loans 79.80%   79.80%   81.80%  
Loans and Leases Receivable, Related Parties $ 24,800,351   $ 24,800,351   $ 21,586,729  
Loans held for investment $ 23,719,186   $ 23,719,186   $ 20,486,415  
Financing Receivable Ratio of Nonperforming Loans to All Loans and Other Real Estate 0.52%   0.52%   0.69%  
Loans and leases receivable, nonaccrual loans $ 116,900   $ 116,900   $ 137,200  
Financing Receivable, Allowance for Credit Losses on Loans $ 382,800   $ 382,800   $ 333,700  
Allowance for Credit Losses as Percentage of Loans 1.53%   1.53%   1.53%  
Provision for credit losses $ 0 $ 0 $ 0 $ 0    
Decrease in allowance for credit losses for loans     $ (49,100)      
Increase in allowance for credit losses for loans, percentage     14.70%      
Net charge-offs 2,183 $ 3,017 $ 43,492 $ 5,721    
Revolving Loans 2,350,828   2,350,828      
Allowance for credit losses on off-balance sheet credit exposures 37,646   37,646   $ 37,646  
Commitments expected to fund 1,730,000   1,730,000      
Nonaccrual loans 116,911   116,911   137,217  
American Bank Holding Corporation [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Financing Receivable, Allowance for Credit Losses on Loans 47,500   47,500      
Southwest Bancshares Inc [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Financing Receivable, Allowance for Credit Losses on Loans 45,100   45,100      
Troubled Debt Restructuring [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Allowance for credit losses on off-balance sheet credit exposures 37,600   37,600   37,600  
PCD Loans [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Net charge-offs 962          
Revolving Loans 36,161   36,161      
General reserve 10,300          
PCD Loans [Member] | Merger [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Revolving Loans 53,300   53,300      
PCD Loans [Member] | American Bank Holding Corporation [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Financing Receivable, Allowance for Credit Losses on Loans 27,500   27,500      
PCD Loans [Member] | Southwest Bancshares Inc [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Financing Receivable, Allowance for Credit Losses on Loans 25,800   25,800      
PSLs Loans [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Revolving Loans 12,300   12,300      
PSLs Loans [Member] | Merger [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Revolving Loans 39,300   39,300      
PSLs Loans [Member] | American Bank Holding Corporation [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Financing Receivable, Allowance for Credit Losses on Loans 20,000   20,000      
PSLs Loans [Member] | Southwest Bancshares Inc [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Financing Receivable, Allowance for Credit Losses on Loans 19,300   19,300      
Nonperforming Financial Instruments [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Loans held for investment 130,600   130,600   150,800  
Commercial and Industrial Loans [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Net charge-offs     39,200      
Related Party [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Loans and Leases Receivable, Related Parties $ 3,660   $ 3,660   $ 272 $ 266