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Investment Securities - Investments in Debt and Equity Securities Reported Less than Historical Cost (Details) - Investments reported at less than historical cost - USD ($) $ in Thousands | Mar. 31, 2022 | Dec. 31, 2021
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Schedule of Investments [Line Items] |  |
Historical cost | $ 1,655,027 | $ 658,858
Fair value | 1,535,489 | 645,218
Gross unrealized losses | $ 119,538 | $ 13,640
Percent of the Corporation's investments available for sale | 71.00% | 27.50%

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