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Fair Value Accounting (Financial Instruments Measured at Fair Value on Recurring Basis) (Details) - USD ($) $ in Thousands | Sep. 30, 2021 | Dec. 31, 2020
--- | --- | ---
Assets |  |
Investment securities available for sale | $ 10,481,071 | $ 7,962,438
Mortgage loans held for sale | 152,258 | 216,647
Mortgage-backed securities issued by U.S. Government agencies |  |
Assets |  |
Investment securities available for sale | 872,217 | 1,218,017
Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises |  |
Assets |  |
Investment securities available for sale | 1,057,488 | 1,250,377
Asset-backed securities |  |
Assets |  |
Investment securities available for sale | 650,000 |
U.S. Treasury securities |  |
Assets |  |
Investment securities available for sale | 117,893 | 20,257
Mortgage-backed securities issued by U.S. Government sponsored enterprises |  |
Assets |  |
Investment securities available for sale | 7,270,933 | 5,000,046
Commercial mortgage-backed securities issued by U.S. Government agencies or sponsored enterprises |  |
Assets |  |
Investment securities available for sale | 438,523 | 370,921
Corporate debt securities and other debt securities |  |
Assets |  |
Investment securities available for sale | 19,028 | 20,500
Level 1 |  |
Assets |  |
Trading securities | 0 | 0
Investment securities available for sale | 117,893 | 20,257
Private equity investments | 0 | 0
Other investments | 0 |
Mutual funds and mutual funds held in rabbi trusts | 42,002 | 37,650
GGL/SBA loans servicing asset | 0 | 0
Derivative assets | 0 | 0
Liabilities |  |
Trading liability for short positions |  | 0
Mutual funds held in rabbi trusts | 25,396 | 20,752
Earnout liability |  | 0
Derivative liabilities | 0 | 0
Level 2 |  |
Assets |  |
Trading securities | 6,876 | 10,880
Investment securities available for sale | 10,363,178 | 7,940,160
Private equity investments | 0 | 0
Other investments | 0 |
Mutual funds and mutual funds held in rabbi trusts | 0 | 0
GGL/SBA loans servicing asset | 0 | 0
Derivative assets | 244,991 | 401,295
Liabilities |  |
Trading liability for short positions |  | 7,717
Mutual funds held in rabbi trusts | 0 | 0
Earnout liability |  | 0
Derivative liabilities | 109,320 | 155,119
Level 3 |  |
Assets |  |
Trading securities | 0 | 0
Investment securities available for sale | 0 | 2,021
Private equity investments | 991 | 1,021
Other investments | 10,000 |
Mutual funds and mutual funds held in rabbi trusts | 0 | 0
GGL/SBA loans servicing asset | 3,388 | 3,258
Derivative assets | 0 | 0
Liabilities |  |
Trading liability for short positions |  | 0
Mutual funds held in rabbi trusts | 0 | 0
Earnout liability |  | 5,677
Derivative liabilities | 1,171 | 2,048
Fair Value, Measurements, Recurring Basis |  |
Assets |  |
Trading securities | 6,876 | 10,880
Investment securities available for sale | 10,481,071 | 7,962,438
Mortgage loans held for sale | 152,258 | 216,647
Private equity investments | 991 | 1,021
Other investments | 10,000 | 0
Mutual funds and mutual funds held in rabbi trusts | 42,002 | 37,650
GGL/SBA loans servicing asset | 3,388 | 3,258
Derivative assets | 244,991 | 401,295
Liabilities |  |
Trading liability for short positions | 0 | 7,717
Mutual funds held in rabbi trusts | 25,396 | 20,752
Earnout liability | 0 | 5,677
Derivative liabilities | 110,491 | 157,167
Fair Value, Measurements, Recurring Basis | Mortgage-backed securities issued by U.S. Government agencies |  |
Assets |  |
Trading securities | 0 | 10,185
Investment securities available for sale | 872,217 | 1,218,017
Fair Value, Measurements, Recurring Basis | Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises |  |
Assets |  |
Trading securities | 1,660 | 158
Investment securities available for sale | 1,057,488 | 1,250,377
Fair Value, Measurements, Recurring Basis | Other mortgage-backed securities |  |
Assets |  |
Trading securities | 94 | 178
Fair Value, Measurements, Recurring Basis | State and municipal securities |  |
Assets |  |
Trading securities | 1,007 | 176
Fair Value, Measurements, Recurring Basis | Asset-backed securities |  |
Assets |  |
Trading securities | 4,115 | 183
Investment securities available for sale | 650,000 | 0
Fair Value, Measurements, Recurring Basis | U.S. Treasury securities |  |
Assets |  |
Investment securities available for sale | 117,893 | 20,257
Fair Value, Measurements, Recurring Basis | U.S. Government agency securities |  |
Assets |  |
Investment securities available for sale | 54,989 | 82,320
Fair Value, Measurements, Recurring Basis | Mortgage-backed securities issued by U.S. Government sponsored enterprises |  |
Assets |  |
Investment securities available for sale | 7,270,933 | 5,000,046
Fair Value, Measurements, Recurring Basis | Commercial mortgage-backed securities issued by U.S. Government agencies or sponsored enterprises |  |
Assets |  |
Investment securities available for sale | 438,523 | 370,921
Fair Value, Measurements, Recurring Basis | Corporate debt securities and other debt securities |  |
Assets |  |
Investment securities available for sale | 19,028 | 20,500
Fair Value, Measurements, Recurring Basis | Level 1 |  |
Assets |  |
Trading securities | 0 | 0
Investment securities available for sale | 117,893 | 20,257
Mortgage loans held for sale | 0 | 0
Private equity investments | 0 | 0
Other investments | 0 | 0
Mutual funds and mutual funds held in rabbi trusts | 42,002 | 37,650
GGL/SBA loans servicing asset | 0 | 0
Derivative assets | 0 | 0
Liabilities |  |
Trading liability for short positions | 0 | 0
Mutual funds held in rabbi trusts | 25,396 | 20,752
Earnout liability | 0 | 0
Derivative liabilities | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 1 | Mortgage-backed securities issued by U.S. Government agencies |  |
Assets |  |
Trading securities | 0 | 0
Investment securities available for sale | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 1 | Collateralized mortgage obligations issued by U.S. Government agencies or 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
Investment securities available for sale | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 1 | U.S. Treasury securities |  |
Assets |  |
Investment securities available for sale | 117,893 | 20,257
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 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 | 6,876 | 10,880
Investment securities available for sale | 10,363,178 | 7,940,160
Mortgage loans held for sale | 152,258 | 216,647
Private equity investments | 0 | 0
Other investments | 0 | 0
Mutual funds and mutual funds held in rabbi trusts | 0 | 0
GGL/SBA loans servicing asset | 0 | 0
Derivative assets | 244,991 | 401,295
Liabilities |  |
Trading liability for short positions | 0 | 7,717
Mutual funds held in rabbi trusts | 0 | 0
Earnout liability | 0 | 0
Derivative liabilities | 109,320 | 155,119
Fair Value, Measurements, Recurring Basis | Level 2 | Mortgage-backed securities issued by U.S. Government agencies |  |
Assets |  |
Trading securities | 0 | 10,185
Investment securities available for sale | 872,217 | 1,218,017
Fair Value, Measurements, Recurring Basis | Level 2 | Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises |  |
Assets |  |
Trading securities | 1,660 | 158
Investment securities available for sale | 1,057,488 | 1,250,377
Fair Value, Measurements, Recurring Basis | Level 2 | Other mortgage-backed securities |  |
Assets |  |
Trading securities | 94 | 178
Fair Value, Measurements, Recurring Basis | Level 2 | State and municipal securities |  |
Assets |  |
Trading securities | 1,007 | 176
Fair Value, Measurements, Recurring Basis | Level 2 | Asset-backed securities |  |
Assets |  |
Trading securities | 4,115 | 183
Investment securities available for sale | 650,000 | 0
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 | 54,989 | 82,320
Fair Value, Measurements, Recurring Basis | Level 2 | Mortgage-backed securities issued by U.S. Government sponsored enterprises |  |
Assets |  |
Investment securities available for sale | 7,270,933 | 5,000,046
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 | 438,523 | 370,921
Fair Value, Measurements, Recurring Basis | Level 2 | Corporate debt securities and other debt securities |  |
Assets |  |
Investment securities available for sale | 19,028 | 18,479
Fair Value, Measurements, Recurring Basis | Level 3 |  |
Assets |  |
Trading securities | 0 | 0
Investment securities available for sale | 0 | 2,021
Mortgage loans held for sale | 0 | 0
Private equity investments | 991 | 1,021
Other investments | 10,000 | 0
Mutual funds and mutual funds held in rabbi trusts | 0 | 0
GGL/SBA loans servicing asset | 3,388 | 3,258
Derivative assets | 0 | 0
Liabilities |  |
Trading liability for short positions | 0 | 0
Mutual funds held in rabbi trusts | 0 | 0
Earnout liability | 0 | 5,677
Derivative liabilities | 1,171 | 2,048
Fair Value, Measurements, Recurring Basis | Level 3 | Mortgage-backed securities issued by U.S. Government agencies |  |
Assets |  |
Trading securities | 0 | 0
Investment securities available for sale | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 3 | Collateralized mortgage obligations issued by U.S. Government agencies or 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
Investment securities available for sale | 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 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 | $ 2,021

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