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Loans and Allowance for Credit Losses - Additional Information (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended |  |  |
--- | --- | --- | --- | --- | ---
Sep. 30, 2025 | Sep. 30, 2024 | Jun. 30, 2024 | Sep. 30, 2025 | Sep. 30, 2024 | Jun. 30, 2025 | Dec. 31, 2024 | Dec. 31, 2023
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 | 81.70% |  |  | 81.70% |  |  | 81.30% |
Loans and Leases Receivable, Related Parties | $ 100 |  |  | $ 100 |  |  | $ 266 | $ 292
Loans held for investment | $ 20,738,294 |  |  | $ 20,738,294 |  |  | $ 21,057,616 |
Financing Receivable Ratio of Nonperforming Loans to All Loans and Other Real Estate | 0.54% |  |  | 0.54% |  |  | 0.37% |
Loans and leases receivable, nonaccrual loans | $ 105,500 |  |  | $ 105,500 |  |  | $ 73,600 |
Financing Receivable, Allowance for Credit Losses on Loans | $ 339,600 |  |  | $ 339,600 |  |  | $ 351,800 |
Allowance for Credit Losses as Percentage of Loans | 1.54% |  |  | 1.54% |  |  | 1.59% |
Provision for credit losses | $ 0 |  |  | $ 0 | $ 7,923 |  |  |
Provision for credit losses | 0 | $ 9,100 |  | 0 | 9,066 |  |  |
Decrease in allowance for credit losses for loans |  |  |  | $ (12,200) |  |  |  |
Increase in allowance for credit losses for loans, percentage |  |  |  | 3.50% |  |  |  |
Net charge-offs | 6,458 | 5,455 |  | $ 12,179 | 11,966 |  |  |
General reserve |  |  |  | 15,000 |  |  |  |
Allowance for credit losses on off-balance sheet credit exposures | 37,646 | $ 37,646 | $ 37,646 | 37,646 | $ 37,646 | $ 37,646 | $ 37,646 | $ 36,503
Commitments expected to fund | 1,420,000 |  |  | 1,420,000 |  |  |  |
Nonaccrual loans | 105,529 |  |  | 105,529 |  |  | 73,647 |
LSSB Merger [Member] |  |  |  |  |  |  |  |
Accounts Notes And Loans Receivable [Line Items] |  |  |  |  |  |  |  |
Provision for credit losses |  |  | 7,900 |  |  |  |  |
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 |
Troubled Debt Restructuring [Member] | LSSB Merger [Member] |  |  |  |  |  |  |  |
Accounts Notes And Loans Receivable [Line Items] |  |  |  |  |  |  |  |
Provision for credit losses |  |  | $ 1,200 |  |  |  |  |
PCD Loans [Member] |  |  |  |  |  |  |  |
Accounts Notes And Loans Receivable [Line Items] |  |  |  |  |  |  |  |
Net charge-offs | 4,500 |  |  |  |  |  |  |
Nonperforming Financial Instruments [Member] |  |  |  |  |  |  |  |
Accounts Notes And Loans Receivable [Line Items] |  |  |  |  |  |  |  |
Loans held for investment | $ 119,600 |  |  | $ 119,600 |  |  | $ 81,500 |

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