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Accumulated Other Comprehensive Loss (Tables) | 12 Months Ended
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Dec. 31, 2020
Accumulated Other Comprehensive Loss [Abstract] |
Schedule of Accumulated Other Comprehensive Loss, Net of Tax | Accumulated other comprehensive loss, net of tax, consisted of the following as of December 31 (dollars in thousands):
|  | 2020 |  |  | 2019 |
Unfunded benefit obligation for pensions and other postretirement benefit plans - net of taxes of $3,822 and $2,727, respectively |  | $ | 14,378 |  |  | $ | 10,259 |
Reclassification out of Accumulated Other Comprehensive Income | The following table details the reclassifications out of accumulated other comprehensive loss by component for the years ended December 31 (dollars in thousands):
|  | Amounts Reclassified from Accumulated Other Comprehensive Loss |
Details about Accumulated Other Comprehensive Loss Components (Affected Line Item in Statements of Income) |  | 2020 |  |  | 2019 |  |  | 2018 |
Amortization of defined benefit pension items |  |  |  |  |  |  |  |  |  |  |  |
Amortization of net prior service cost (a) |  | $ | (794 | ) |  | $ | (794 | ) |  | $ | (904 | )
Amortization of net loss (a) |  |  | 5,586 |  |  |  | 17,074 |  |  |  | (15,554 | )
Adjustment due to effects of regulation (a) |  |  | (10,006 | ) |  |  | (19,309 | ) |  |  | 18,947 |
Total before tax (b) |  |  | (5,214 | ) |  |  | (3,029 | ) |  |  | 2,489 |
Tax expense (b) |  |  | 1,095 |  |  |  | 636 |  |  |  | (523 | )
Net of tax (b) |  | $ | (4,119 | ) |  | $ | (2,393 | ) |  | $ | 1,966 |
| (a) | These accumulated other comprehensive loss components are included in the computation of net periodic pension cost (see Note 11 for additional details).
| (b) | Description is also the affected line item on the Consolidated Statements of Income

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