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Fair Value Accounting - Financial Instruments Measured At Fair Value On A Recurring Basis (Details) - USD ($) $ in Thousands | Mar. 31, 2024 | Dec. 31, 2023
--- | --- | ---
Assets |  |
Investment securities available for sale | $ 9,694,515 | $ 9,788,662
Mortgage loans held for sale | 36,698 | 47,338
Collateralized mortgage obligations issued by U.S. Government sponsored enterprises |  |
Assets |  |
Investment securities available for sale | 564,940 | 587,595
U.S. Treasury securities |  |
Assets |  |
Investment securities available for sale | 615,409 | 597,629
Mortgage-backed securities issued by U.S. Government agencies |  |
Assets |  |
Investment securities available for sale | 911,918 | 925,664
Mortgage-backed securities issued by U.S. Government sponsored enterprises |  |
Assets |  |
Investment securities available for sale | 6,182,911 | 6,430,379
Commercial mortgage-backed securities issued by U.S. Government agencies or sponsored enterprises |  |
Assets |  |
Investment securities available for sale | 1,381,730 | 1,209,783
Corporate debt securities and other debt securities |  |
Assets |  |
Investment securities available for sale | 8,824 | 8,672
Level 1 |  |
Assets |  |
Trading securities | 0 | 0
Investment securities available for sale | 615,409 | 597,629
Other investments | 0 | 0
Mutual funds and mutual funds held in rabbi trusts | 59,649 | 53,742
Derivative assets | 0 | 0
Liabilities |  |
Securities sold short | 2,469 | 3,496
Mutual funds held in rabbi trusts | 44,759 | 38,735
Derivative liabilities | 0 | 0
Level 2 |  |
Assets |  |
Trading securities | 7,411 | 12,898
Investment securities available for sale | 9,079,106 | 9,191,033
Other investments | 0 | 0
Mutual funds and mutual funds held in rabbi trusts | 0 | 0
Derivative assets | 103,589 | 94,903
Liabilities |  |
Securities sold short | 0 | 0
Mutual funds held in rabbi trusts | 0 | 0
Derivative liabilities | 286,094 | 259,650
Level 3 |  |
Assets |  |
Trading securities | 0 | 0
Investment securities available for sale | 0 | 0
Other investments | 13,115 | 12,560
Mutual funds and mutual funds held in rabbi trusts | 0 | 0
Derivative assets | 0 | 0
Liabilities |  |
Securities sold short | 0 | 0
Mutual funds held in rabbi trusts | 0 | 0
Derivative liabilities | 0 | 0
Fair Value, Measurements, Recurring Basis |  |
Assets |  |
Trading securities | 7,411 | 12,898
Investment securities available for sale | 9,694,515 | 9,788,662
Mortgage loans held for sale | 36,698 | 47,338
Other investments | 13,115 | 12,560
Mutual funds and mutual funds held in rabbi trusts | 59,649 | 53,742
Derivative assets | 103,589 | 94,903
Liabilities |  |
Securities sold short | 2,469 | 3,496
Mutual funds held in rabbi trusts | 44,759 | 38,735
Derivative liabilities | 286,094 | 259,650
Fair Value, Measurements, Recurring Basis | Collateralized mortgage obligations issued by U.S. Government sponsored enterprises |  |
Assets |  |
Trading securities | 2,914 | 2,910
Investment securities available for sale | 564,940 | 587,595
Fair Value, Measurements, Recurring Basis | Other mortgage-backed securities |  |
Assets |  |
Trading securities | 0 | 2,149
Fair Value, Measurements, Recurring Basis | State and municipal securities |  |
Assets |  |
Trading securities | 72 | 0
Fair Value, Measurements, Recurring Basis | Asset-backed securities |  |
Assets |  |
Trading securities | 4,425 | 7,839
Fair Value, Measurements, Recurring Basis | U.S. Treasury securities |  |
Assets |  |
Investment securities available for sale | 615,409 | 597,629
Fair Value, Measurements, Recurring Basis | U.S. Government agency securities |  |
Assets |  |
Investment securities available for sale | 28,783 | 28,940
Fair Value, Measurements, Recurring Basis | Mortgage-backed securities issued by U.S. Government agencies |  |
Assets |  |
Investment securities available for sale | 911,918 | 925,664
Fair Value, Measurements, Recurring Basis | Mortgage-backed securities issued by U.S. Government sponsored enterprises |  |
Assets |  |
Investment securities available for sale | 6,182,911 | 6,430,379
Fair Value, Measurements, Recurring Basis | Commercial mortgage-backed securities issued by U.S. Government agencies or sponsored enterprises |  |
Assets |  |
Investment securities available for sale | 1,381,730 | 1,209,783
Fair Value, Measurements, Recurring Basis | Corporate debt securities and other debt securities |  |
Assets |  |
Investment securities available for sale | 8,824 | 8,672
Fair Value, Measurements, Recurring Basis | Level 1 |  |
Assets |  |
Trading securities | 0 | 0
Investment securities available for sale | 615,409 | 597,629
Mortgage loans held for sale | 0 | 0
Other investments | 0 | 0
Mutual funds and mutual funds held in rabbi trusts | 59,649 | 53,742
Derivative assets | 0 | 0
Liabilities |  |
Securities sold short | 2,469 | 3,496
Mutual funds held in rabbi trusts | 44,759 | 38,735
Derivative liabilities | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 1 | Collateralized mortgage obligations issued by U.S. Government sponsored enterprises |  |
Assets |  |
Trading securities | 0 | 0
Investment securities available for sale | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 1 | Other mortgage-backed securities |  |
Assets |  |
Trading securities | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 1 | State and municipal securities |  |
Assets |  |
Trading securities | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 1 | Asset-backed securities |  |
Assets |  |
Trading securities | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 1 | U.S. Treasury securities |  |
Assets |  |
Investment securities available for sale | 615,409 | 597,629
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 | 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 |  |
Trading securities | 7,411 | 12,898
Investment securities available for sale | 9,079,106 | 9,191,033
Mortgage loans held for sale | 36,698 | 47,338
Other investments | 0 | 0
Mutual funds and mutual funds held in rabbi trusts | 0 | 0
Derivative assets | 103,589 | 94,903
Liabilities |  |
Securities sold short | 0 | 0
Mutual funds held in rabbi trusts | 0 | 0
Derivative liabilities | 286,094 | 259,650
Fair Value, Measurements, Recurring Basis | Level 2 | Collateralized mortgage obligations issued by U.S. Government sponsored enterprises |  |
Assets |  |
Trading securities | 2,914 | 2,910
Investment securities available for sale | 564,940 | 587,595
Fair Value, Measurements, Recurring Basis | Level 2 | Other mortgage-backed securities |  |
Assets |  |
Trading securities | 0 | 2,149
Fair Value, Measurements, Recurring Basis | Level 2 | State and municipal securities |  |
Assets |  |
Trading securities | 72 | 0
Fair Value, Measurements, Recurring Basis | Level 2 | Asset-backed securities |  |
Assets |  |
Trading securities | 4,425 | 7,839
Fair Value, Measurements, Recurring Basis | Level 2 | U.S. Treasury securities |  |
Assets |  |
Investment securities available for sale | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 2 | U.S. Government agency securities |  |
Assets |  |
Investment securities available for sale | 28,783 | 28,940
Fair Value, Measurements, Recurring Basis | Level 2 | Mortgage-backed securities issued by U.S. Government agencies |  |
Assets |  |
Investment securities available for sale | 911,918 | 925,664
Fair Value, Measurements, Recurring Basis | Level 2 | Mortgage-backed securities issued by U.S. Government sponsored enterprises |  |
Assets |  |
Investment securities available for sale | 6,182,911 | 6,430,379
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 | 1,381,730 | 1,209,783
Fair Value, Measurements, Recurring Basis | Level 2 | Corporate debt securities and other debt securities |  |
Assets |  |
Investment securities available for sale | 8,824 | 8,672
Fair Value, Measurements, Recurring Basis | Level 3 |  |
Assets |  |
Trading securities | 0 | 0
Investment securities available for sale | 0 | 0
Mortgage loans held for sale | 0 | 0
Other investments | 13,115 | 12,560
Mutual funds and mutual funds held in rabbi trusts | 0 | 0
Derivative assets | 0 | 0
Liabilities |  |
Securities sold short | 0 | 0
Mutual funds held in rabbi trusts | 0 | 0
Derivative liabilities | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 3 | Collateralized mortgage obligations issued by U.S. Government sponsored enterprises |  |
Assets |  |
Trading securities | 0 | 0
Investment securities available for sale | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 3 | Other mortgage-backed securities |  |
Assets |  |
Trading securities | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 3 | State and municipal securities |  |
Assets |  |
Trading securities | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 3 | Asset-backed securities |  |
Assets |  |
Trading securities | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 3 | U.S. Treasury securities |  |
Assets |  |
Investment securities available for sale | 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 | 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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