XML 38 R25.htm IDEA: XBRL DOCUMENT
v3.21.1

Employee Benefit Plans: (Tables) | 3 Months Ended
--- | ---
Mar. 31, 2021
Retirement Benefits [Abstract] |
Schedule of components of net periodic benefit costs, before allocation to the overhead pool, for Registrant's pension plan, postretirement plan, and SERP | The components of net periodic benefit costs for Registrant’s pension plan, postretirement medical benefit plan, and SERP for the three months ended March 31, 2021 and 2020 were as follows:
|  | For The Three Months Ended March 31,
|  | Pension Benefits |  | Other Postretirement Benefits |  | SERP
(dollars in thousands) |  | 2021 |  | 2020 |  | 2021 |  | 2020 |  | 2021 |  | 2020
Components of Net Periodic Benefits Cost: |  |  |  |  |  |  |  |  |  |  |  |
Service cost |  | $ | 1,625 |  |  | $ | 1,408 |  |  | $ | 40 |  |  | $ | 47 |  |  | $ | 348 |  |  | $ | 244 |
Interest cost |  | 1,712 |  |  | 1,954 |  |  | 31 |  |  | 56 |  |  | 229 |  |  | 247 |
Expected return on plan assets |  | (3,134) |  |  | (2,950) |  |  | (134) |  |  | (127) |  |  | — |  |  | — |
Amortization of prior service cost |  | 109 |  |  | 109 |  |  | — |  |  | — |  |  | — |  |  | — |
Amortization of actuarial (gain) loss |  | 993 |  |  | 442 |  |  | (287) |  |  | (199) |  |  | 419 |  |  | 211 |
Net periodic benefits costs under accounting standards |  | 1,305 |  |  | 963 |  |  | (350) |  |  | (223) |  |  | 996 |  |  | 702 |
Regulatory adjustment - deferred |  | (351) |  |  | (93) |  |  | — |  |  | — |  |  | — |  |  | — |
Total expense (benefit) recognized, before surcharges and allocation to overhead pool |  | $ | 954 |  |  | $ | 870 |  |  | $ | (350) |  |  | $ | (223) |  |  | $ | 996 |  |  | $ | 702 |

X
- References No definition available. + Details
Name: | us-gaap_CompensationAndRetirementDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the components of net benefit costs for pension plans and/or other employee benefit plans including service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) recognized due to settlements or curtailments. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
Name: | us-gaap_ScheduleOfNetBenefitCostsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration