Jointly Owned Facilities (Details) $ in Thousands	Dec. 31, 2020 USD ($)
Wyodak Plant \| Electric Utilities
Jointly Owned Utility Plant Interests [Line Items]
Ownership Share Percentage	20.00%
Plant in Service	$ 116,074
Construction Work in Progress	2,249
Less Accumulated Depreciation	(67,762)
Plant Net of Accumulated Depreciation	$ 50,561
Transmission Tie \| Electric Utilities
Jointly Owned Utility Plant Interests [Line Items]
Ownership Share Percentage	35.00%
Plant in Service	$ 26,176
Construction Work in Progress	509
Less Accumulated Depreciation	(7,103)
Plant Net of Accumulated Depreciation	$ 19,582
Wygen III Generating Facility \| Electric Utilities
Jointly Owned Utility Plant Interests [Line Items]
Ownership Share Percentage	52.00%
Plant in Service	$ 142,739
Construction Work in Progress	582
Less Accumulated Depreciation	(24,783)
Plant Net of Accumulated Depreciation	$ 118,538
Wygen I Generating Facility \| Power Generation
Jointly Owned Utility Plant Interests [Line Items]
Ownership Share Percentage	76.50%
Plant in Service	$ 114,975
Construction Work in Progress	318
Less Accumulated Depreciation	(49,459)
Plant Net of Accumulated Depreciation	$ 65,834

The period end amount owned by the reporting utility of a jointly owned utility plant in service.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 980
-SubTopic 360
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 10.C)
-URI http://asc.fasb.org/extlink&oid=115995737&loc=d3e659983-123033

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

The total period end amount of plant in service and construction in progress net of accumulated depreciation for the utility's share of jointly owned electricity generation plant.

+ References

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- Definition

The period end amount of construction work in progress at a jointly owned electricity generation plant.

+ References

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- Definition

The period end amount of accumulated depreciation in a jointly owned electricity generation plant.

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- Definition

The proportionate share of interest (percent) in a jointly owned utility plant.

+ References

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