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Investment Securities, Equity Securities with Readily Determinable Fair Values and Other Investments - Contractual Maturities and Estimated Fair Values (Details) - USD ($) | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2025 | Jun. 30, 2024 | Jun. 30, 2025 | Jun. 30, 2024 | Dec. 31, 2024
Amortized Cost |  |  |  |  |
Due in one year or less, held-to-maturity debt securities amortized cost | $ 3,200,000 |  | $ 3,200,000 |  |
Due after one year through five years, held-to-maturity debt securities amortized cost | 1,200,000 |  | 1,200,000 |  |
Amortized cost, held-to-maturity debt securities | 4,400,000 |  | 4,400,000 |  | $ 4,400,000
Fair Value |  |  |  |  |
Due in one year or less, held-to-maturity debt securities, Estimated fair value | 3,200,000 |  | 3,200,000 |  |
Due after one year through five years, held-to-maturity debt securities, Estimated fair value | 1,200,000 |  | 1,200,000 |  |
Estimated fair value | 4,400,000 |  | 4,400,000 |  | 4,400,000
Available-for-sale debt securities amortized cost disclosures |  |  |  |  |
Due after five years through ten years, available-for-sale debt securities amortized cost | 2,240,000 |  | 2,240,000 |  |
Due after ten years, available-for-sale debt securities amortized cost | 150,190,000 |  | 150,190,000 |  |
Residential mortgage-backed securities, available-for-sale debt securities amortized cost | 5,245,239,000 |  | 5,245,239,000 |  |
Amortized cost, Available-for-sale securities | 5,397,669,000 |  | 5,397,669,000 |  | 5,472,310,000
Available for sale debt securities, Estimated Fair Value Disclosures |  |  |  |  |
Due after five years through ten years, available-for-sale debt securities, Estimated Fair Value | 2,238,000 |  | 2,238,000 |  |
Due after ten years, available-for-sale debt securities, Estimated Fair Value | 138,527,000 |  | 138,527,000 |  |
Residential mortgage-backed securities, available-for-sale debt securities, Estimated Fair Value | 4,869,078,000 |  | 4,869,078,000 |  |
Estimated fair value, Available for sale securities | 5,009,843,000 |  | 5,009,843,000 |  | $ 4,987,916,000
Available for sale debt securities, Estimated Fair Value Disclosures |  |  |  |  |
Proceeds from sales and calls of available for sale securities | 730,000 | $ 0 | 4,235,000 | $ 1,720,000 |
Proceeds from sales of mortgage-backed securities | 0 | 0 | 0 | 0 |
Gross gains realized on sales | 0 | 0 | 0 | 0 |
Gross losses realized on sales | 0 | $ 0 | 0 | $ 0 |
Collateral pledged |  |  |  |  |
Available-for-sale debt securities amortized cost disclosures |  |  |  |  |
Amortized cost, Available-for-sale securities | 1,720,908,000 |  | 1,720,908,000 |  |
Available for sale debt securities, Estimated Fair Value Disclosures |  |  |  |  |
Fair value of available for sale investment securities pledged | $ 1,532,931,000 |  | $ 1,532,931,000 |  |

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