Derivative Instruments - Schedule of Notional Amounts of Outstanding Derivative Positions (Details) - NW Natural therm in Thousands, $ in Thousands |
Jun. 30, 2026
USD ($)
therm
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Dec. 31, 2025
USD ($)
therm
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Jun. 30, 2025
USD ($)
therm
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| Foreign Exchange | |||
| Derivative [Line Items] | |||
| Foreign exchange | $ | $ 9,233 | $ 8,596 | $ 10,155 |
| Financial | Natural Gas Therms | |||
| Derivative [Line Items] | |||
| Natural gas (in therms) | 785,220 | 757,895 | 807,000 |
| Physical | Natural Gas Therms | |||
| Derivative [Line Items] | |||
| Natural gas (in therms) | 959,775 | 692,275 | 811,360 |
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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. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Nominal number of units used to calculate payment on derivative. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Nominal or face amount used to calculate payment on derivative. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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