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Fair Value - Schedule of Quantitative Information (Details) - Natural Gas Exchange Agreements [Member] $ in Thousands | 12 Months Ended |
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Dec. 31, 2020 USD ($) MMBTU $ / MMBTU | Dec. 31, 2019 USD ($)
Purchase [Member] | Minimum [Member] | Internally Derived Weighted Average Cost Of Gas [Member] |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items] |  |
Derivative, Forward Price | 1.71 |
Transaction/Delivery Volumes | MMBTU | 130,000 |
Purchase [Member] | Maximum [Member] | Internally Derived Weighted Average Cost Of Gas [Member] |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items] |  |
Derivative, Forward Price | 2.54 |
Transaction/Delivery Volumes | MMBTU | 310,000 |
Purchase [Member] | Weighted Average [Member] | Internally Derived Weighted Average Cost Of Gas [Member] |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items] |  |
Derivative, Forward Price | 2.01 |
Sales [Member] | Minimum [Member] | Internally Derived Weighted Average Cost Of Gas [Member] |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items] |  |
Derivative, Forward Price | 1.76 |
Transaction/Delivery Volumes | MMBTU | 75,000 |
Sales [Member] | Maximum [Member] | Internally Derived Weighted Average Cost Of Gas [Member] |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items] |  |
Derivative, Forward Price | 4.16 |
Transaction/Delivery Volumes | MMBTU | 310,000 |
Sales [Member] | Weighted Average [Member] | Internally Derived Weighted Average Cost Of Gas [Member] |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items] |  |
Derivative, Forward Price | 3.22 |
Fair Value, Recurring [Member] |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items] |  |
Derivative Liability | $ | $ (8,410) | $ (2,976)

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- Definition Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13433-108611 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226008-175313 + Details
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