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Property, Plant and Equipment - Summary of Property, Plant and Equipment (Details) - USD ($) $ in Thousands | Dec. 31, 2022 | Dec. 31, 2021
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Property, Plant and Equipment [Line Items] |  |
Property, Plant and Equipment, net of accumulated depreciation | $ 2,212,717 | $ 2,124,605
Electric Plant in Service |  |
Property, Plant and Equipment [Line Items] |  |
Property, plant and equipment, gross | 2,958,311 | 2,833,371
Less Accumulated Depreciation and Amortization | 859,988 | 817,302
Property, Plant and Equipment, net of accumulated depreciation | 2,098,323 | 2,016,069
Nonelectric Property, Plant and Equipment |  |
Property, Plant and Equipment [Line Items] |  |
Property, plant and equipment, gross | 309,098 | 290,561
Less Accumulated Depreciation and Amortization | 194,704 | 182,025
Property, Plant and Equipment, net of accumulated depreciation | 114,394 | 108,536
Production | Electric Plant in Service |  |
Property, Plant and Equipment [Line Items] |  |
Property, plant and equipment, gross | 1,343,097 | 1,332,067
Transmission | Electric Plant in Service |  |
Property, Plant and Equipment [Line Items] |  |
Property, plant and equipment, gross | 756,848 | 722,739
Distribution | Electric Plant in Service |  |
Property, Plant and Equipment [Line Items] |  |
Property, plant and equipment, gross | 612,716 | 574,488
General | Electric Plant in Service |  |
Property, Plant and Equipment [Line Items] |  |
Property, plant and equipment, gross | 131,718 | 129,151
Electric Plant in Service | Electric Plant in Service |  |
Property, Plant and Equipment [Line Items] |  |
Property, plant and equipment, gross | 2,844,379 | 2,758,445
Construction Work in Progress | Electric Plant in Service |  |
Property, Plant and Equipment [Line Items] |  |
Property, plant and equipment, gross | 113,932 | 74,926
Construction Work in Progress | Nonelectric Property, Plant and Equipment |  |
Property, Plant and Equipment [Line Items] |  |
Property, plant and equipment, gross | 15,170 | 16,611
Equipment | Nonelectric Property, Plant and Equipment |  |
Property, Plant and Equipment [Line Items] |  |
Property, plant and equipment, gross | 218,770 | 203,390
Buildings and Leasehold Improvements | Nonelectric Property, Plant and Equipment |  |
Property, Plant and Equipment [Line Items] |  |
Property, plant and equipment, gross | 61,506 | 56,908
Land | Nonelectric Property, Plant and Equipment |  |
Property, Plant and Equipment [Line Items] |  |
Property, plant and equipment, gross | 13,652 | 13,652
Nonelectric Property, Plant and Equipment | Nonelectric Property, Plant and Equipment |  |
Property, Plant and Equipment [Line Items] |  |
Property, plant and equipment, gross | $ 293,928 | $ 273,950

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