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Fair Value Measurement - Recurring and Nonrecurring Basis (Details) - USD ($) $ in Thousands | Mar. 31, 2022 | Dec. 31, 2021
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Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Securities available for sale, at estimated fair value |  | $ 2,065,984 | $ 2,764,325
Derivative assets | [1] | 2,781 | 13,412
Derivative liabilities | [1] | 4,003 | 2,194
US Treasury Securities |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Securities available for sale, at estimated fair value |  |  | 58,877
State and political subdivisions |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Securities available for sale, at estimated fair value |  | 1,566,185 | 2,051,936
Corporate bonds and other |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Securities available for sale, at estimated fair value |  | 141,326 | 135,532
Residential MBS |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Securities available for sale, at estimated fair value | [2] | 280,691 | 426,350
Commercial MBS |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Securities available for sale, at estimated fair value | [2] | 77,782 | 91,630
Fair Value, Recurring |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Equity investments |  | 5,645 | 5,920
Total asset fair value measurements |  | 2,099,587 | 2,788,476
Total liability fair value measurements |  | 7,682 | 19,823
Fair Value, Recurring | State and political subdivisions |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Securities available for sale, at estimated fair value |  | 1,566,185 | 2,051,936
Fair Value, Recurring | Corporate bonds and other |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Securities available for sale, at estimated fair value |  | 141,326 | 135,532
Fair Value, Recurring | Residential MBS |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Securities available for sale, at estimated fair value | [3] | 280,691 | 426,350
Fair Value, Recurring | Commercial MBS |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Securities available for sale, at estimated fair value | [3] | 77,782 | 91,630
Fair Value, Recurring | Interest Rate Swap |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Derivative assets |  | 27,958 | 18,231
Derivative liabilities |  | 7,682 | 19,823
Fair Value, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Equity investments |  | 5,645 | 5,920
Total asset fair value measurements |  | 5,645 | 64,797
Total liability fair value measurements |  | 0 | 0
Fair Value, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | State and political subdivisions |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Securities available for sale, at estimated fair value |  | 0 | 0
Fair Value, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate bonds and other |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Securities available for sale, at estimated fair value |  | 0 | 0
Fair Value, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Residential MBS |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Securities available for sale, at estimated fair value | [3] | 0 | 0
Fair Value, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Commercial MBS |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Securities available for sale, at estimated fair value | [3] | 0 | 0
Fair Value, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Interest Rate Swap |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Derivative assets |  | 0 | 0
Derivative liabilities |  | 0 | 0
Fair Value, Recurring | Significant Other Observable Inputs (Level 2) |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Equity investments |  | 0 | 0
Total asset fair value measurements |  | 2,093,942 | 2,723,679
Total liability fair value measurements |  | 7,682 | 19,823
Fair Value, Recurring | Significant Other Observable Inputs (Level 2) | State and political subdivisions |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Securities available for sale, at estimated fair value |  | 1,566,185 | 2,051,936
Fair Value, Recurring | Significant Other Observable Inputs (Level 2) | Corporate bonds and other |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Securities available for sale, at estimated fair value |  | 141,326 | 135,532
Fair Value, Recurring | Significant Other Observable Inputs (Level 2) | Residential MBS |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Securities available for sale, at estimated fair value | [3] | 280,691 | 426,350
Fair Value, Recurring | Significant Other Observable Inputs (Level 2) | Commercial MBS |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Securities available for sale, at estimated fair value | [3] | 77,782 | 91,630
Fair Value, Recurring | Significant Other Observable Inputs (Level 2) | Interest Rate Swap |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Derivative assets |  | 27,958 | 18,231
Derivative liabilities |  | 7,682 | 19,823
Fair Value, Recurring | Significant Unobservable Inputs (Level 3) |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Equity investments |  | 0 | 0
Total asset fair value measurements |  | 0 | 0
Total liability fair value measurements |  | 0 | 0
Fair Value, Recurring | Significant Unobservable Inputs (Level 3) | State and political subdivisions |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Securities available for sale, at estimated fair value |  | 0 | 0
Fair Value, Recurring | Significant Unobservable Inputs (Level 3) | Corporate bonds and other |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Securities available for sale, at estimated fair value |  | 0 | 0
Fair Value, Recurring | Significant Unobservable Inputs (Level 3) | Residential MBS |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Securities available for sale, at estimated fair value | [3] | 0 | 0
Fair Value, Recurring | Significant Unobservable Inputs (Level 3) | Commercial MBS |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Securities available for sale, at estimated fair value | [3] | 0 | 0
Fair Value, Recurring | Significant Unobservable Inputs (Level 3) | Interest Rate Swap |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Derivative assets |  | 0 | 0
Derivative liabilities |  | 0 | 0
Fair Value, Nonrecurring |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Total asset fair value measurements |  | 8,449 | 8,458
Fair Value, Nonrecurring | Collateral-dependent loans |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Collateral-dependent loans | [4] | 8,449 | 8,458
Fair Value, Nonrecurring | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Total asset fair value measurements |  | 0 | 0
Fair Value, Nonrecurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Collateral-dependent loans |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Collateral-dependent loans | [4] | 0 | 0
Fair Value, Nonrecurring | Significant Other Observable Inputs (Level 2) |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Total asset fair value measurements |  | 0 | 0
Fair Value, Nonrecurring | Significant Other Observable Inputs (Level 2) | Collateral-dependent loans |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Collateral-dependent loans | [4] | 0 | 0
Fair Value, Nonrecurring | Significant Unobservable Inputs (Level 3) |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Total asset fair value measurements |  | 8,449 | 8,458
Fair Value, Nonrecurring | Significant Unobservable Inputs (Level 3) | Collateral-dependent loans |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Collateral-dependent loans | [4] | $ 8,449 | $ 8,458
[1] | Net derivative assets are included in other assets and net derivative liabilities are included in other liabilities on the consolidated balance sheets. Included in the fair value of net derivative assets and net derivative liabilities are credit valuation adjustments reflecting counterparty credit risk and our credit risk. We had no credit exposure related to interest rate swaps with financial institutions and $2.8 million related to interest rate swaps with customers at March 31, 2022. We had no credit exposure related to interest rate swaps with financial institutions and $13.4 million related to interest rate swaps with customers at December 31, 2021. The credit risk associated with customer transactions is partially mitigated as these are generally secured by the non-cash collateral securing the underlying transaction being hedged.
[2] | All MBS are issued and/or guaranteed by U.S. government agencies or U.S. GSEs.
[3] | All MBS are issued and/or guaranteed by U.S. government agencies or U.S. GSEs.
[4] | Consists of individually evaluated loans. Loans for which the fair value of the collateral and commercial real estate fair value of the properties is less than cost basis are presented net of allowance. Losses on these loans represent charge-offs which are netted against the allowance for loan losses.

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