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Investment Securities (Investment Securities, At Fair Value) (Details) - USD ($) $ in Thousands | Jun. 30, 2025 | Dec. 31, 2024 | Jun. 30, 2024 | Mar. 31, 2024 | Dec. 31, 2023
--- | --- | --- | --- | --- | ---
Investment Securities [Abstract] |  |  |  |  |  |
Available for sale debt securities |  | $ 8,915,779 | $ 9,136,853 |  |  |
Trading debt securities |  | 46,630 | 38,034 |  |  |
Equity securities with a readily determinable fair value |  | 45,098 | 48,359 |  |  |
Equity Securities without Readily Determinable Fair Value, Amount |  | 9,413 | 9,083 | $ 65,780 | $ 6,988 | $ 6,978
Federal Reserve Bank Stock |  | 35,736 | 35,545 |  |  |
Federal Home Loan Bank Stock |  | 10,100 | 10,120 |  |  |
Private equity investments |  | 174,070 | 184,386 |  |  |
Total investment securities | [1] | 9,236,826 | 9,462,380 |  |  |
Interest Receivable, Current |  | $ 36,100 | $ 35,000 |  |  |
[1] | (1)Accrued interest receivable totaled $36.1 million and $35.0 million at June 30, 2025 and December 31, 2024, respectively, and was included within other assets on the consolidated balance sheets.

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