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Benefit Plans (Fair values of our pension plan assets by asset category) (Details) - USD ($) $ in Thousands | Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
--- | --- | --- | ---
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair values of the Corporation's pension plan assets | $ 7,066 | $ 6,582 | $ 8,649
Level 2 [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair values of the Corporation's pension plan assets | 7,066 | 6,582 |
Short-term investments [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair values of the Corporation's pension plan assets | 103 | 235 |
Short-term investments [Member] | Level 2 [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair values of the Corporation's pension plan assets | 103 | 235 |
Fixed income [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair values of the Corporation's pension plan assets | 3,273 | 2,983 |
Fixed income [Member] | Level 2 [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair values of the Corporation's pension plan assets | 3,273 | 2,983 |
Equity investments [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair values of the Corporation's pension plan assets | 3,690 | 3,364 |
Equity investments [Member] | Level 2 [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair values of the Corporation's pension plan assets | $ 3,690 | $ 3,364 |

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