Environmental Matters (Details)	12 Months Ended
	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Accrual for Environmental Loss Contingencies [Abstract]
Site Contingency, Number of Remediation Projects	2
Insurance Proceeds Applied To Prudently Incurred Remediation Costs	$ 3,600,000
Environmental Regulatory Table [Abstract]
Regulatory Assets, Current	72,391,000	$ 31,745,000
Regulatory Assets, Noncurrent	$ 314,579,000	348,927,000
Insurance Proceeds, Amortization Period	10 years 6 months
Cost Recovery Period	3 years
WASHINGTON
Environmental Activity [Line Items]
Remediation Recovery Percentage	3.30%
Northwest Natural Gas Company [Member]
Environmental Activity [Line Items]
Remediation Recovery Percentage	96.70%
Accrual for Environmental Loss Contingencies [Abstract]
Environmental Current Liabilities	$ 26,985,000	28,241,000
Environmental Noncurrent Liabilities	88,851,000	92,281,000
EPA Record Of Decision, Clean-Up Costs, Portland Harbor	1,050,000,000.00
Annual Tariff Rider Collection	5,000,000
Environmental Settlement Insurance Proceeds Received To Date	150,000,000
Annual insurance proceeds to appy against remediation costs	5,000,000
Insurance Proceeds Applied To Prudently Incurred Remediation Costs	90,000,000
Environmental Regulatory Table [Abstract]
Regulatory Assets, Current	72,391,000	31,745,000
Regulatory Assets, Noncurrent	314,539,000	348,887,000
Annual Insurance Proceeds to Apply Against Remediation Costs	5,000,000.0
Total Annual Remediation Expense and Interest	10,000,000.0
Northwest Natural Gas Company [Member] | Minimum [Member]
Accrual for Environmental Loss Contingencies [Abstract]
EPA Record Of Decision, Clean-Up Costs, Portland Harbor	(0.30)
Northwest Natural Gas Company [Member] | Maximum [Member]
Accrual for Environmental Loss Contingencies [Abstract]
EPA Record Of Decision, Clean-Up Costs, Portland Harbor	0.50
Northwest Natural Gas Company [Member] | Gasco Siltronic Sediments [Member]
Accrual for Environmental Loss Contingencies [Abstract]
Environmental Current Liabilities	7,582,000	7,596,000
Environmental Noncurrent Liabilities	42,076,000	43,725,000
Northwest Natural Gas Company [Member] | Portland Harbor Other [Member]
Accrual for Environmental Loss Contingencies [Abstract]
Environmental Current Liabilities	2,592,000	1,942,000
Environmental Noncurrent Liabilities	9,570,000	7,020,000
Northwest Natural Gas Company [Member] | Gasco Upland [Member]
Accrual for Environmental Loss Contingencies [Abstract]
Environmental Current Liabilities	15,711,000	14,887,000
Environmental Noncurrent Liabilities	36,215,000	40,250,000
Northwest Natural Gas Company [Member] | Front Street [Member]
Accrual for Environmental Loss Contingencies [Abstract]
Environmental Current Liabilities	1,100,000	3,816,000
Environmental Noncurrent Liabilities	811,000	1,107,000
Northwest Natural Gas Company [Member] | Oregon Steel Mills [Member]
Accrual for Environmental Loss Contingencies [Abstract]
Environmental Current Liabilities	0	0
Environmental Noncurrent Liabilities	179,000	179,000
Northwest Natural Gas Company [Member] | Environmental Restoration Costs [Member]
Environmental Regulatory Table [Abstract]
Environmental Regulatory Deferred Cost and Interest	45,122,000	44,516,000
Environmental Regulatory Accrued Site Liabilities	115,773,000	120,352,000
Environmental Regulatory Insurance Proceeds and Interest	(59,564,000)	(69,253,000)
Regulatory Assets, Current	6,694,000	4,992,000
Regulatory Assets, Noncurrent	94,636,000	90,623,000
Regulatory Assets	101,331,000	95,615,000
Northwest Natural Gas Company [Member] | Environmental Restoration Costs [Member] | Front Street [Member]
Environmental Regulatory Table [Abstract]
Environmental Regulatory Accrued Site Liabilities	100,000	$ 200,000
Front Street [Member] | Northwest Natural Gas Company [Member]
Accrual for Environmental Loss Contingencies [Abstract]
Liability For Studies And Design Costs	$ 1,900,000
Portland Harbor [Member]
Accrual for Environmental Loss Contingencies [Abstract]
Number Of Potentially Responsible Parties	one hundred
Gasco Siltronic Sediments [Member] | Minimum [Member]
Accrual for Environmental Loss Contingencies [Abstract]
Environmental Exit Costs, Anticipated Cost	$ 49,700,000
Gasco Siltronic Sediments [Member] | Maximum [Member]
Accrual for Environmental Loss Contingencies [Abstract]
Environmental Exit Costs, Anticipated Cost	350,000,000
Gasco Siltronic Sediments [Member] | Northwest Natural Gas Company [Member]
Accrual for Environmental Loss Contingencies [Abstract]
Environmental Project Liability	$ 49,700,000
Yakama Nation [Member] | Portland Harbor Other [Member]
Accrual for Environmental Loss Contingencies [Abstract]
Trustee Council Members - Number of Claimants	1
Site Contingency, Number of Other Third-Party Defendants	29
NRD Liability Claim Yakama Nation	$ 300,000
Number of Amended Complaints Filed	2