Derivative Instruments Notional Amounts - Northwest Natural Gas Company [Member] therm in Thousands, $ in Thousands	Mar. 31, 2023 USD ($) therm	Dec. 31, 2022 USD ($) therm	Mar. 31, 2022 USD ($) therm
Gas Year 2021-2022 | Oregon [Member]
Derivative [Line Items]
TargetHedgeAchieved	84.00%
Financial [Member] | Gas Year 2021-2022 | Oregon [Member]
Derivative [Line Items]
TargetHedgeAchieved	67.00%
Physical [Member] | Gas Year 2021-2022 | Oregon [Member]
Derivative [Line Items]
TargetHedgeAchieved	17.00%
Natural Gas Therms [Member] | Financial [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	681,850	852,435	449,710
Natural Gas Therms [Member] | Physical [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	295,382	463,254	317,840
Foreign Exchange Contract [Member]
Derivative [Line Items]
Derivative, Notional Amount | $	$ 10,444	$ 7,617	$ 5,216