Property, Plant and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment, Net, by Type [Abstract]
Property, Plant and Equipment, Gross	$ 4,261,566	$ 3,997,243
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	1,147,166	1,125,873
Total property, plant, and equipment, net	3,114,400	2,871,370
Property, Plant, Equipment non-cash	25,318	38,333
Regulatory Liability, Noncurrent	689,578	658,332
Natural Gas Distribution [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Property, Plant and Equipment, Gross	3,992,676	3,721,939
Public Utilities, Property, Plant and Equipment, Construction Work in Progress	78,897	135,398
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	1,115,690	1,098,715
Total property, plant, and equipment, net	2,955,883	2,758,622
Other Northwest Natural [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Property, Plant and Equipment, Gross	70,368	69,332
Public Utilities, Property, Plant and Equipment, Construction Work in Progress	6,606	4,971
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	21,541	20,646
Total property, plant, and equipment, net	55,433	53,657
Northwest Natural Gas Company [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Total property, plant, and equipment, net	3,011,316	2,812,279
Property, Plant, Equipment non-cash	24,584	37,537
Northwest Holdings Other [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Property, Plant and Equipment, Gross	92,979	57,184
Public Utilities, Property, Plant and Equipment, Construction Work in Progress	20,040	8,419
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	9,935	6,512
Total property, plant, and equipment, net	$ 103,084	$ 59,091
Natural Gas Distribution [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service	3.00%	3.00%	3.00%
Other Northwest Natural [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Weighted Average Depreciation Rates	1.80%	1.80%	1.80%
Northwest Natural Gas Company [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Property, Plant and Equipment, Gross	$ 4,148,547	$ 3,931,640
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	1,137,231	1,119,361
Total property, plant, and equipment, net	3,011,316	2,812,279
Regulatory Liability, Noncurrent	688,599	657,350
Northwest Natural Gas Company [Member] | Asset Removal Costs [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Regulatory Liability, Noncurrent	$ 467,742	$ 445,952