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v3.20.4

Variable Interest Entities (Details) $ in Thousands | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2020 USD ($) MW | Dec. 31, 2019 USD ($) | Dec. 31, 2018 USD ($)
Variable Interest Entity [Line Items] |  |  |
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets | $ 6,402,097 | $ 6,082,456 | $ 5,782,576
Limited Partnerships and Similar Entities [Member] |  |  |
Variable Interest Entity [Line Items] |  |  |
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets | 56,200 |  |
Variable Interest Entity Remaining Investment Commitment Amount | $ 30,700 |  |
Minimum [Member] | Limited Partnerships and Similar Entities [Member] |  |  |
Variable Interest Entity [Line Items] |  |  |
Variable Interest Entity, Restrictions on Withdrawal of Member Capital Account | 2021 |  |
Maximum [Member] | Limited Partnerships and Similar Entities [Member] |  |  |
Variable Interest Entity [Line Items] |  |  |
Variable Interest Entity, Restrictions on Withdrawal of Member Capital Account | 2040 |  |
Variable Interest Entity, Not Primary Beneficiary [Member] | Limited Partnerships and Similar Entities [Member] | VIE Commitments [Member] |  |  |
Variable Interest Entity [Line Items] |  |  |
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets | $ 51,200 |  |
Lancaster Power Purchase Agreement [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] |  |  |
Variable Interest Entity [Line Items] |  |  |
Evaluated Power Capacity | MW | 270 |  |
Variable Interest Entity, Reporting Entity Involvement, Contractual Commitment, Amount | $ 175,100 |  |
Lancaster Power Purchase Agreement [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Minimum [Member] |  |  |
Variable Interest Entity [Line Items] |  |  |
Average service lives for the utility plan in service | 15 years |  |
Lancaster Power Purchase Agreement [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Maximum [Member] |  |  |
Variable Interest Entity [Line Items] |  |  |
Average service lives for the utility plan in service | 25 years |  |

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- Definition Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(11)) -URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08(g)(1)(ii)) -URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 28 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=75031198&loc=d3e14064-108612 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (bb) -URI http://asc.fasb.org/extlink&oid=121559654&loc=d3e5710-111685 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 45 -Paragraph 25 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=116870748&loc=SL6758485-165988 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 32 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8933-108599 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 22 -URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8736-108599 Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(12)) -URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910 Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571 Reference 10: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 30 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8906-108599 + Details
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