Derivative Instruments - Schedule of Notional Amounts (Details) - Northwest Natural Gas Company [Member] therm in Thousands, $ in Thousands	Dec. 31, 2021 USD ($) therm	Dec. 31, 2020 USD ($) therm
Natural Gas Therms [Member] | Financial [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	618,815	784,400
Natural Gas Therms [Member] | Physical [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	431,628	457,593
Foreign Exchange Contract [Member]
Derivative [Line Items]
Derivative, Notional Amount | $	$ 6,268	$ 5,896