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Fair Value Accounting - Schedule of Assets and Liabilities Measured at Estimated Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands | Sep. 30, 2025 | Dec. 31, 2024
--- | --- | ---
Assets |  |
Investment securities available for sale | $ 7,575,468 | $ 7,551,018
Mortgage loans held for sale | 41,083 | 33,448
Derivatives Not Designated as Hedging Instruments |  |
Liabilities |  |
Estimated fair value of derivative liabilities | 120,958 | 201,917
Visa derivative | Derivatives Not Designated as Hedging Instruments |  |
Liabilities |  |
Estimated fair value of derivative liabilities | 2,964 | 64
U.S. Treasury securities |  |
Assets |  |
Investment securities available for sale | 1,221,154 | 1,212,742
Mortgage-backed securities issued by U.S. Government agencies |  |
Assets |  |
Investment securities available for sale | 1,429,706 | 1,462,790
Mortgage-backed securities issued by U.S. Government sponsored enterprises |  |
Assets |  |
Investment securities available for sale | 2,006,151 | 2,034,035
Collateralized mortgage obligations issued by U.S. Government sponsored enterprises |  |
Assets |  |
Investment securities available for sale | 519,199 | 550,201
Commercial mortgage-backed securities issued by U.S. Government agencies or sponsored enterprises |  |
Assets |  |
Investment securities available for sale | 2,360,210 | 2,253,116
Corporate debt securities and other debt securities |  |
Assets |  |
Investment securities available for sale | 9,191 | 8,971
Level 1 |  |
Assets |  |
Total trading securities | 2,004 | 0
Investment securities available for sale | 1,221,154 | 1,212,742
Other investments | 0 | 0
Mutual funds and mutual funds held in rabbi trusts | 72,883 | 63,371
Derivative assets | 0 | 0
Liabilities |  |
Mutual funds held in rabbi trusts | 57,339 | 48,351
Derivative liabilities | 0 | 0
Level 2 |  |
Assets |  |
Total trading securities | 19,185 | 9,713
Investment securities available for sale | 6,354,314 | 6,338,276
Other investments | 0 | 0
Mutual funds and mutual funds held in rabbi trusts | 0 | 0
Derivative assets | 85,822 | 83,895
Liabilities |  |
Mutual funds held in rabbi trusts | 0 | 0
Derivative liabilities | 117,994 | 216,325
Level 3 |  |
Assets |  |
Total trading securities | 0 | 0
Investment securities available for sale | 0 | 0
Other investments | 18,012 | 14,831
Mutual funds and mutual funds held in rabbi trusts | 0 | 0
Derivative assets | 0 | 0
Liabilities |  |
Mutual funds held in rabbi trusts | 0 | 0
Derivative liabilities | 0 | 0
Fair Value, Measurements, Recurring Basis |  |
Assets |  |
Total trading securities | 21,189 | 9,713
Investment securities available for sale | 7,575,468 | 7,551,018
Mortgage loans held for sale | 41,083 | 33,448
Other investments | 18,012 | 14,831
Mutual funds and mutual funds held in rabbi trusts | 72,883 | 63,371
Derivative assets | 85,822 | 83,895
Liabilities |  |
Mutual funds held in rabbi trusts | 57,339 | 48,351
Derivative liabilities | 117,994 | 216,325
Fair Value, Measurements, Recurring Basis | U.S. Treasury securities |  |
Assets |  |
Total trading securities | 2,004 | 0
Investment securities available for sale | 1,221,154 | 1,212,742
Fair Value, Measurements, Recurring Basis | State and municipal securities |  |
Assets |  |
Total trading securities | 658 | 473
Fair Value, Measurements, Recurring Basis | Asset-backed securities |  |
Assets |  |
Total trading securities | 18,524 | 9,240
Fair Value, Measurements, Recurring Basis | Other Investments |  |
Assets |  |
Total trading securities | 3 | 0
Fair Value, Measurements, Recurring Basis | U.S. Government agency securities |  |
Assets |  |
Investment securities available for sale | 29,857 | 29,163
Fair Value, Measurements, Recurring Basis | Mortgage-backed securities issued by U.S. Government agencies |  |
Assets |  |
Investment securities available for sale | 1,429,706 | 1,462,790
Fair Value, Measurements, Recurring Basis | Mortgage-backed securities issued by U.S. Government sponsored enterprises |  |
Assets |  |
Investment securities available for sale | 2,006,151 | 2,034,035
Fair Value, Measurements, Recurring Basis | Collateralized mortgage obligations issued by U.S. Government sponsored enterprises |  |
Assets |  |
Investment securities available for sale | 519,199 | 550,201
Fair Value, Measurements, Recurring Basis | Commercial mortgage-backed securities issued by U.S. Government agencies or sponsored enterprises |  |
Assets |  |
Investment securities available for sale | 2,360,210 | 2,253,116
Fair Value, Measurements, Recurring Basis | Corporate debt securities and other debt securities |  |
Assets |  |
Investment securities available for sale | 9,191 | 8,971
Fair Value, Measurements, Recurring Basis | Level 1 |  |
Assets |  |
Total trading securities | 2,004 | 0
Investment securities available for sale | 1,221,154 | 1,212,742
Mortgage loans held for sale | 0 | 0
Other investments | 0 | 0
Mutual funds and mutual funds held in rabbi trusts | 72,883 | 63,371
Derivative assets | 0 | 0
Liabilities |  |
Mutual funds held in rabbi trusts | 57,339 | 48,351
Derivative liabilities | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 1 | U.S. Treasury securities |  |
Assets |  |
Total trading securities | 2,004 | 0
Investment securities available for sale | 1,221,154 | 1,212,742
Fair Value, Measurements, Recurring Basis | Level 1 | State and municipal securities |  |
Assets |  |
Total trading securities | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 1 | Asset-backed securities |  |
Assets |  |
Total trading securities | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 1 | Other Investments |  |
Assets |  |
Total trading securities | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 1 | U.S. Government agency securities |  |
Assets |  |
Investment securities available for sale | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 1 | Mortgage-backed securities issued by U.S. Government agencies |  |
Assets |  |
Investment securities available for sale | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 1 | Mortgage-backed securities issued by U.S. Government sponsored enterprises |  |
Assets |  |
Investment securities available for sale | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 1 | Collateralized mortgage obligations issued by U.S. Government sponsored enterprises |  |
Assets |  |
Investment securities available for sale | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 1 | Commercial mortgage-backed securities issued by U.S. Government agencies or sponsored enterprises |  |
Assets |  |
Investment securities available for sale | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 1 | Corporate debt securities and other debt securities |  |
Assets |  |
Investment securities available for sale | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 2 |  |
Assets |  |
Total trading securities | 19,185 | 9,713
Investment securities available for sale | 6,354,314 | 6,338,276
Mortgage loans held for sale | 41,083 | 33,448
Other investments | 0 | 0
Mutual funds and mutual funds held in rabbi trusts | 0 | 0
Derivative assets | 85,822 | 83,895
Liabilities |  |
Mutual funds held in rabbi trusts | 0 | 0
Derivative liabilities | 117,994 | 216,325
Fair Value, Measurements, Recurring Basis | Level 2 | U.S. Treasury securities |  |
Assets |  |
Total trading securities | 0 | 0
Investment securities available for sale | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 2 | State and municipal securities |  |
Assets |  |
Total trading securities | 658 | 473
Fair Value, Measurements, Recurring Basis | Level 2 | Asset-backed securities |  |
Assets |  |
Total trading securities | 18,524 | 9,240
Fair Value, Measurements, Recurring Basis | Level 2 | Other Investments |  |
Assets |  |
Total trading securities | 3 | 0
Fair Value, Measurements, Recurring Basis | Level 2 | U.S. Government agency securities |  |
Assets |  |
Investment securities available for sale | 29,857 | 29,163
Fair Value, Measurements, Recurring Basis | Level 2 | Mortgage-backed securities issued by U.S. Government agencies |  |
Assets |  |
Investment securities available for sale | 1,429,706 | 1,462,790
Fair Value, Measurements, Recurring Basis | Level 2 | Mortgage-backed securities issued by U.S. Government sponsored enterprises |  |
Assets |  |
Investment securities available for sale | 2,006,151 | 2,034,035
Fair Value, Measurements, Recurring Basis | Level 2 | Collateralized mortgage obligations issued by U.S. Government sponsored enterprises |  |
Assets |  |
Investment securities available for sale | 519,199 | 550,201
Fair Value, Measurements, Recurring Basis | Level 2 | Commercial mortgage-backed securities issued by U.S. Government agencies or sponsored enterprises |  |
Assets |  |
Investment securities available for sale | 2,360,210 | 2,253,116
Fair Value, Measurements, Recurring Basis | Level 2 | Corporate debt securities and other debt securities |  |
Assets |  |
Investment securities available for sale | 9,191 | 8,971
Fair Value, Measurements, Recurring Basis | Level 3 |  |
Assets |  |
Total trading securities | 0 | 0
Investment securities available for sale | 0 | 0
Mortgage loans held for sale | 0 | 0
Other investments | 18,012 | 14,831
Mutual funds and mutual funds held in rabbi trusts | 0 | 0
Derivative assets | 0 | 0
Liabilities |  |
Mutual funds held in rabbi trusts | 0 | 0
Derivative liabilities | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 3 | U.S. Treasury securities |  |
Assets |  |
Total trading securities | 0 | 0
Investment securities available for sale | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 3 | State and municipal securities |  |
Assets |  |
Total trading securities | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 3 | Asset-backed securities |  |
Assets |  |
Total trading securities | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 3 | Other Investments |  |
Assets |  |
Total trading securities | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 3 | U.S. Government agency securities |  |
Assets |  |
Investment securities available for sale | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 3 | Mortgage-backed securities issued by U.S. Government agencies |  |
Assets |  |
Investment securities available for sale | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 3 | Mortgage-backed securities issued by U.S. Government sponsored enterprises |  |
Assets |  |
Investment securities available for sale | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 3 | Collateralized mortgage obligations issued by U.S. Government sponsored enterprises |  |
Assets |  |
Investment securities available for sale | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 3 | Commercial mortgage-backed securities issued by U.S. Government agencies or sponsored enterprises |  |
Assets |  |
Investment securities available for sale | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 3 | Corporate debt securities and other debt securities |  |
Assets |  |
Investment securities available for sale | $ 0 | $ 0

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- Definition Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. 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