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Investment Securities - Narrative (Details) | 12 Months Ended
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Dec. 31, 2025 USD ($) security | Dec. 31, 2024 USD ($) security | Dec. 31, 2023 USD ($)
Debt Securities, Available-for-sale [Line Items] |  |  |
Investment securities available-for-sale | $ 1,688,768,000 | $ 895,034,000 |
Debt securities, unrealized gain (loss) | (27,500,000) | (69,400,000) |
AFS, debt securities, unrealized loss position | $ 552,922,000 | $ 705,274,000 |
Percentage of securities in unrealized loss positions, available-for-sale securities | 32.70% | 78.80% |
AFS, debt securities, unrealized loss position, accumulated loss | $ 44,650,000 | $ 70,222,000 |
Debt Securities, Available For Sale, Accrued Interest, After Allowance For Credit Loss, Statement of Financial Position Extensible List Not Disclosed Flag | Accrued interest receivables | Accrued interest receivables |
Accrued interest receivable | $ 7,200,000 | $ 4,100,000 |
Number of days past due to be placed in nonaccrual status | 90 days |  |
Payments to acquired AFS debt securities | $ 33,126,000 | 148,476,000 | $ 362,905,000
Estimated fair value of debt securities have right to call or prepay the obligations | 965,200,000 | 118,600,000 |
Estimated fair value of debt securities have right to call or prepay the obligations, scheduled maturities less than one year | 12,400,000 | 4,800,000 |
Estimated fair value of debt securities have right to call or prepay the obligations, scheduled maturities of after one year through five years | 111,400,000 | 67,400,000 |
Estimated fair value of debt securities have right to call or prepay the obligations, scheduled maturities after five years through ten years | 157,100,000 | 38,900,000 |
Estimated fair value of debt securities have right to call or prepay the obligations, scheduled maturities of which is after 10 years | 684,300,000 | 7,500,000 |
Proceeds from sales of investment securities available-for-sale | 176,312,000 | 0 | $ 229,981,000
Gain (loss) on sale of securities | 0 |  |
GSE debt securities excluding specified securities |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Investment securities available-for-sale | 285,400,000 | 36,900,000 |
US treasury and government |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Investment securities available-for-sale | 173,677,000 | 176,294,000 |
Debt securities, unrealized gain (loss) | $ (11,800,000) | $ (18,800,000) |
Available-for-sale, qualitative disclosure, number of positions | security | 38 | 34 |
Number of securities in unrealized loss positions | security | 17 | 23 |
Payments to acquired AFS debt securities | $ 0 | $ 0 |
GSE CMOs |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Investment securities available-for-sale | 496,600,000 | 55,500,000 |
Debt securities, unrealized gain (loss) | $ (3,900,000) | $ (7,000,000.0) |
Available-for-sale, qualitative disclosure, number of positions | security | 136 | 59 |
Number of securities in unrealized loss positions | security | 57 | 57 |
Payments to acquired AFS debt securities | $ 19,900,000 | $ 0 |
GSE mortgage-related securities |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Investment securities available-for-sale | 325,700,000 | 148,300,000 |
Debt securities, unrealized gain (loss) | $ (8,700,000) | $ (18,600,000) |
Available-for-sale, qualitative disclosure, number of positions | security | 194 | 141 |
Number of securities in unrealized loss positions | security | 85 | 92 |
Payments to acquired AFS debt securities | $ 0 | $ 4,100,000 |
Municipal obligations |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Investment securities available-for-sale | 240,216,000 | 20,254,000 |
Debt securities, unrealized gain (loss) | $ 8,300,000 | $ (300,000) |
Available-for-sale, qualitative disclosure, number of positions | security | 242 | 39 |
Number of securities in unrealized loss positions | security | 12 |  |
Payments to acquired AFS debt securities | $ 2,800,000 | $ 11,700,000 |
Corporate debt obligations |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Investment securities available-for-sale | 40,023,000 | 12,287,000 |
Debt securities, unrealized gain (loss) | $ 800,000 | $ 100,000 |
Available-for-sale, qualitative disclosure, number of positions | security | 16 | 4 |
Number of securities in unrealized loss positions | security | 2 | 1 |
Payments to acquired AFS debt securities | $ 0 | $ 0 |
U.S. treasury bonds |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Investment securities available-for-sale | 412,000,000.0 | 481,900,000 |
Debt securities, unrealized gain (loss) | $ (12,200,000) | $ (24,800,000) |
Available-for-sale, qualitative disclosure, number of positions | security | 54 | 65 |
Number of securities in unrealized loss positions | security | 25 | 50 |
Payments to acquired AFS debt securities | $ 9,900,000 | $ 132,700,000 |
Foreign government obligations |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Investment securities available-for-sale | $ 500,000 | $ 499,000 |
Available-for-sale, qualitative disclosure, number of positions | security | 1 | 1 |
Collateral Pledged |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Available for sale securities pledged as collateral | $ 1,200,000,000 | $ 792,000,000.0 |
Outstanding borrowings | $ 0 | $ 0 |

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