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Selected Balance Sheet Information: Materials and Supplies (Details) - USD ($) $ in Thousands | Mar. 31, 2021 | Dec. 31, 2020
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Selected Balance Sheet Information [Abstract] |  |
Materials and supplies | $ 88,088 | $ 85,250
Fuel - Electric Utilities | 1,590 | 1,531
Natural gas in storage | 12,925 | 30,619
Total materials, supplies and fuel | $ 102,603 | $ 117,400

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- Definition Carrying amount as of the balance sheet date of natural gas in storage, which is a mixture of gases (liquefied or otherwise), used for fuel and manufacturing purposes, which is ready for sale. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.6(a)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
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