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Employee Postretirement Benefits - Amounts Recognized in Consolidated Balance Sheets (Details) - USD ($) $ in Thousands | Dec. 31, 2021 | Dec. 31, 2020
--- | --- | ---
Pension Plan |  |
Regulatory Assets: |  |
Unrecognized Prior Service Cost | $ 0 | $ 0
Unrecognized Actuarial Loss | 102,737 | 137,500
Total Regulatory Assets | 102,737 | 137,500
Accumulated Other Comprehensive Loss: |  |
Unrecognized Prior Service Cost | 0 | 0
Unrecognized Actuarial (Gain) Loss | (1,020) | 128
Total Accumulated Other Comprehensive Loss | (1,020) | 128
Executive Survivor and Supplemental Retirement Plan |  |
Regulatory Assets: |  |
Unrecognized Prior Service Cost | 0 | 0
Unrecognized Actuarial Loss | 2,525 | 2,681
Total Regulatory Assets | 2,525 | 2,681
Accumulated Other Comprehensive Loss: |  |
Unrecognized Prior Service Cost | 0 | 1
Unrecognized Actuarial (Gain) Loss | 10,660 | 12,030
Total Accumulated Other Comprehensive Loss | 10,660 | 12,031
Other Postretirement Benefits Plan |  |
Regulatory Assets: |  |
Unrecognized Prior Service Cost | (13,989) | (19,579)
Unrecognized Actuarial Loss | 26,852 | 32,238
Total Regulatory Assets | 12,863 | 12,659
Accumulated Other Comprehensive Loss: |  |
Unrecognized Prior Service Cost | (242) | (386)
Unrecognized Actuarial (Gain) Loss | (160) | 21
Total Accumulated Other Comprehensive Loss | $ (402) | $ (365)

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- Definition Represents unrecognized actuarial net gains (losses) pertaining to regulatory assets under a defined benefit plan. + References No definition available. + Details
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- Definition Represents the net prior service cost (credit) related to regulatory assets under a defined benefit plan. + References No definition available. + Details
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- Definition Amount, before tax, of accumulated other comprehensive (income) loss for defined benefit plan, that has not been recognized in net periodic benefit cost (credit). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 10A -Subparagraph (i-k) -URI http://asc.fasb.org/extlink&oid=124509347&loc=SL7669646-108580 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14A -URI http://asc.fasb.org/extlink&oid=124509347&loc=SL7669686-108580 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (j) -URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920 + Details
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- Definition Amount, before tax, of accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (j) -URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14A -URI http://asc.fasb.org/extlink&oid=124509347&loc=SL7669686-108580 + Details
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- Definition Amount, before tax, of accumulated other comprehensive (income) loss for cost (credit) of benefit change attributable to participants' prior service from plan amendment or plan initiation of defined benefit plan, that has not been recognized in net periodic benefit cost (credit). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (j) -URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14A -URI http://asc.fasb.org/extlink&oid=124509347&loc=SL7669686-108580 + Details
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