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WUTC (Details 5) - WUTC [Member] - Cascade Natural Gas [Member] - USD ($) | Jul. 01, 2021 | Jun. 01, 2021 | Jan. 08, 2021 | Jul. 24, 2020 | Jun. 19, 2020
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Gas Distribution [Member] |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |
Public Utilities, Requested Rate Increase (Decrease), Amount |  |  |  |  | $ 13,800,000
Public Utilities, Requested Rate Increase (Decrease), Percentage |  |  |  |  | 5.30%
Public Utilities, Requested Rate Increase (Decrease), Amended, Amount |  |  | $ 7,400,000 | $ 14,300,000 |
Public Utilities, Requested Rate Increase (Decrease), Amended, Percentage |  |  | 2.80% | 5.50% |
Gas Distribution [Member] | Subsequent Event [Member] |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |
Public Utilities, Approved Rate Increase (Decrease), Amount | $ (391,000) |  |  |  |
Public Utilities, Approved Rate Increase (Decrease), Percentage | (0.20%) |  |  |  |
Pending Rate Case [Member] | Pipeline Cost Recovery Mechanism [Member] |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |
Public Utilities, Requested Rate Increase (Decrease), Amount |  | $ 2,100,000 |  |  |
Public Utilities, Requested Rate Increase (Decrease), Percentage |  | 0.80% |  |  |

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