Lease Payments to be Received

No definition available.

Name:	nwn_LeasePaymentstobeReceived
Namespace Prefix:	nwn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Lease Payments to be Received, Five Years

+ References

No definition available.

+ Details

Name:	nwn_LeasePaymentstobeReceivedFiveYears
Namespace Prefix:	nwn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Lease Payments to be Received, Four Years

+ References

No definition available.

+ Details

Name:	nwn_LeasePaymentstobeReceivedFourYears
Namespace Prefix:	nwn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Lease Payments to be Received, Remainder of Fiscal Year

+ References

No definition available.

+ Details

Name:	nwn_LeasePaymentstobeReceivedRemainderofFiscalYear
Namespace Prefix:	nwn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Lease Payments to be Received, Thereafter

+ References

No definition available.

+ Details

Name:	nwn_LeasePaymentstobeReceivedThereafter
Namespace Prefix:	nwn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Lease Payments to be Received, Three Years

+ References

No definition available.

+ Details

Name:	nwn_LeasePaymentstobeReceivedThreeYears
Namespace Prefix:	nwn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Lease Payments to be Received, Two Years

+ References

No definition available.

+ Details

Name:	nwn_LeasePaymentstobeReceivedTwoYears
Namespace Prefix:	nwn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Lease Revenue [Abstract]

+ References

No definition available.

+ Details

Name:	nwn_LeaseRevenueAbstract
Namespace Prefix:	nwn_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Operating Leases Payment to be Received [Abstract]

+ References

No definition available.

+ Details

Name:	nwn_OperatingLeasesPaymenttobeReceivedAbstract
Namespace Prefix:	nwn_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Sales-type Leases Payments to be Received [Abstract]

+ References

No definition available.

+ Details

Name:	nwn_SalestypeLeasesPaymentstobeReceivedAbstract
Namespace Prefix:	nwn_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Total Lease Payments to be Received [Abstract]

+ References

No definition available.

+ Details

Name:	nwn_TotalLeasePaymentstobeReceivedAbstract
Namespace Prefix:	nwn_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of lease income from operating, direct financing, and sales-type leases. Includes, but is not limited to, variable lease payments, interest income, profit (loss) recognized at commencement, and lease payments paid and payable to lessor.

+ References

+ Details

Name:	us-gaap_LeaseIncome
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- 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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479773/842-30-50-3

+ Details

Name:	us-gaap_LessorLeaseDescriptionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of lease payments to be received by lessor for operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479773/842-30-50-12

+ Details

Name:	us-gaap_LessorOperatingLeasePaymentsToBeReceived
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of lease payment to be received by lessor for operating lease in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

Name:	us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of lease payment to be received by lessor for operating lease in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

Name:	us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of lease payment to be received by lessor for operating lease in remainder of current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 842
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479773/842-30-50-12

+ Details

Name:	us-gaap_LessorOperatingLeasePaymentsToBeReceivedRemainderOfFiscalYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of lease payment to be received by lessor for operating lease after fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

Name:	us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of lease payment to be received by lessor for operating lease in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

Name:	us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of lease payment to be received by lessor for operating lease in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

Name:	us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Term of lessor's sales-type lease renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 842
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479773/842-30-50-3

+ Details

Name:	us-gaap_LessorSalesTypeLeaseRenewalTerm1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Definition

Term of lessor's sales-type lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

+ Details

Name:	us-gaap_LessorSalesTypeLeaseTermOfContract1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of operating lease income from lease payments and variable lease payments paid and payable to lessor. Includes, but is not limited to, variable lease payments not included in measurement of lease receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479773/842-30-50-5

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 270
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6A
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482964/270-10-50-6A

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479016/842-30-45-3

+ Details

Name:	us-gaap_OperatingLeaseLeaseIncome
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Disclosure of the unamortized amount of the discount on the note or receivable which is deducted from the face amount of the receivable or loan. The discount or premium is the difference between the present value and the face amount.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482925/835-30-45-1A

+ Details

Name:	us-gaap_ReceivableWithImputedInterestDiscount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The receivable or note face amount less the unamortized discount or premium.

+ References

+ Details

Name:	us-gaap_ReceivableWithImputedInterestNetAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of residual asset covered by residual value guarantee. Excludes guarantee considered to be lease payments for lessor.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479773/842-30-50-7

+ Details

Name:	us-gaap_ResidualValueOfLeasedAsset
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of undiscounted cash flows to be received by lessor for sales-type and direct financing leases.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479773/842-30-50-10

+ Details

Name:	us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceived
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of undiscounted cash flows to be received by lessor for sales-type and direct financing leases in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

Name:	us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedFourYears
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of undiscounted cash flows to be received by lessor for sales-type and direct financing leases in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

Name:	us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedNextTwelveMonths
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of undiscounted cash flows to be received by lessor for sales-type and direct financing leases in remainder of current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 842
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479773/842-30-50-10

+ Details

Name:	us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedRemainderOfFiscalYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of undiscounted cash flows to be received by lessor for sales-type and direct financing leases after fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

Name:	us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedThereafter
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of undiscounted cash flows to be received by lessor for sales-type and direct financing leases in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

Name:	us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedThreeYears
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of undiscounted cash flows to be received by lessor for sales-type and direct financing leases in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

Name:	us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedTwoYears
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of lease income from variable lease payments, interest income from net investment on sales-type lease, and profit (loss) recognized at commencement.

+ References

+ Details

Name:	us-gaap_SalesTypeLeaseLeaseIncome
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of cash outflow for variable lease payment excluded from lease liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 5
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479041/842-20-45-5

+ Details

Name:	us-gaap_VariableLeasePayment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	dei_LegalEntityAxis=nwn_NorthwestNaturalGasCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=nwn_OtherNorthwestHoldingsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=nwn_CompressedNaturalGasLeaseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=nwn_NorthMistLeaseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=nwn_SalestypeLeaseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Leases - Lease Revenue - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
Leases - Lease Revenue - USD ($) $ in Thousands	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Lessor, Lease, Description [Line Items]
Lessor, Sales-type Lease, Renewal Term	50 years		50 years
Lessor, Sales-type Lease, Term of Contract	30 years		30 years
Residual Value of Leased Asset	$ 5,700	$ 5,300	$ 5,700	$ 5,300	$ 5,500
Lease Revenue [Abstract]
Total lease revenue	200	200	300	300
Operating Leases Payment to be Received [Abstract]
Operating Lease, Payments to be Received, Remainder of Fiscal Year	328		328
Lessor, Operating Lease, Payment to be Received, Year One	652		652
Operating Lease, Payments to be Received, Two Years	92		92
Operating Lease, Payments to be Received, Three Years	79		79
Operating Lease, Payments to be Received, Four Years	58		58
Operating Lease, Payments to be Received, Thereafter	800		800
Total minimum lease payments	2,009		2,009
Total Lease Payments to be Received [Abstract]
Lease Payments to be Received, Remainder of Fiscal Year	8,139		8,139
Lease Payments to be Received, Two Years	15,958		15,958
Lease Payments to be Received, Three Years	14,993		14,993
Lease Payments to be Received, Four Years	14,600		14,600
Lease Payments to be Received, Five Years	14,041		14,041
Lease Payments to be Received, Thereafter	209,116		209,116
Total minimum lease payments	276,847		276,847
Northwest Natural Gas Company [Member]
Lease Revenue [Abstract]
Operating leases	20	19	42	38
Sales-type leases	4,103	3,993	8,207	7,972
Total lease revenue	4,123	$ 4,012	8,249	$ 8,010
Operating Leases Payment to be Received [Abstract]
Operating Lease, Payments to be Received, Remainder of Fiscal Year	302		302
Lessor, Operating Lease, Payment to be Received, Year One	599		599
Operating Lease, Payments to be Received, Two Years	36		36
Operating Lease, Payments to be Received, Three Years	22		22
Operating Lease, Payments to be Received, Four Years	0		0
Operating Lease, Payments to be Received, Thereafter	0		0
Total minimum lease payments	959		959
Total Lease Payments to be Received [Abstract]
Lease Payments to be Received, Remainder of Fiscal Year	8,113		8,113
Lease Payments to be Received, Two Years	15,905		15,905
Lease Payments to be Received, Three Years	14,937		14,937
Lease Payments to be Received, Four Years	14,543		14,543
Lease Payments to be Received, Five Years	13,983		13,983
Lease Payments to be Received, Thereafter	208,316		208,316
Total minimum lease payments	275,797		275,797
Other Northwest Holdings [Member]
Operating Leases Payment to be Received [Abstract]
Operating Lease, Payments to be Received, Remainder of Fiscal Year	26		26
Lessor, Operating Lease, Payment to be Received, Year One	53		53
Operating Lease, Payments to be Received, Two Years	56		56
Operating Lease, Payments to be Received, Three Years	57		57
Operating Lease, Payments to be Received, Four Years	58		58
Operating Lease, Payments to be Received, Thereafter	800		800
Total minimum lease payments	1,050		1,050
Total Lease Payments to be Received [Abstract]
Lease Payments to be Received, Remainder of Fiscal Year	26		26
Lease Payments to be Received, Two Years	53		53
Lease Payments to be Received, Three Years	56		56
Lease Payments to be Received, Four Years	57		57
Lease Payments to be Received, Five Years	58		58
Lease Payments to be Received, Thereafter	800		800
Total minimum lease payments	$ 1,050		$ 1,050
Compressed Natural Gas Lease [Member]
Lessor, Lease, Description [Line Items]
Lessor, Sales-type Lease, Term of Contract	10 years		10 years
Residual Value of Leased Asset	$ 0		$ 0
Variable Lease, Payment			0
North Mist Lease [Member]
Lessor, Lease, Description [Line Items]
Residual Value of Leased Asset	0		0
Variable Lease, Payment			0
Sales-type Lease [Member]
Sales-type Leases Payments to be Received [Abstract]
Sales-type Lease, Payments to be Received, Remainder of Fiscal Year	7,811		7,811
Sales-Type and Direct Financing Leases, Lease Receivable, to be Received, Year One	15,306		15,306
Sales-type Lease, Payments to be Received, Two Years	14,901		14,901
Sales-type Lease, Payments to be Received, Three Years	14,521		14,521
Sales-type Lease, Payments to be Received, Four Years	13,983		13,983
Sales-type Lease, Payments to be Received, Thereafter	208,316		208,316
Total minimum lease payments	274,838		274,838
Less: imputed interest	148,206		148,206
Total leases receivable	126,632		126,632
Sales-type Lease [Member] \| Northwest Natural Gas Company [Member]
Sales-type Leases Payments to be Received [Abstract]
Sales-type Lease, Payments to be Received, Remainder of Fiscal Year	7,811		7,811
Sales-Type and Direct Financing Leases, Lease Receivable, to be Received, Year One	15,306		15,306
Sales-type Lease, Payments to be Received, Two Years	14,901		14,901
Sales-type Lease, Payments to be Received, Three Years	14,521		14,521
Sales-type Lease, Payments to be Received, Four Years	13,983		13,983
Sales-type Lease, Payments to be Received, Thereafter	208,316		208,316
Total minimum lease payments	274,838		274,838
Less: imputed interest	148,206		148,206
Total leases receivable	126,632		126,632
Sales-type Lease [Member] \| Other Northwest Holdings [Member]
Sales-type Leases Payments to be Received [Abstract]
Sales-type Lease, Payments to be Received, Remainder of Fiscal Year	0		0
Sales-Type and Direct Financing Leases, Lease Receivable, to be Received, Year One	0		0
Sales-type Lease, Payments to be Received, Two Years	0		0
Sales-type Lease, Payments to be Received, Three Years	0		0
Sales-type Lease, Payments to be Received, Four Years	0		0
Sales-type Lease, Payments to be Received, Thereafter	0		0
Total minimum lease payments	$ 0		$ 0