Northwest Natural Holding (NWN) 10-Q 8 Nov 22 2022 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2022	Oct. 27, 2022
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Sep. 30, 2022
Entity Registrant Name	NORTHWEST NATURAL HOLDING COMPANY
Entity File Number	1-38681
Entity Incorporation, State or Country Code	OR
Entity Tax Identification Number	82-4710680
Entity Address, Address Line One	250 SW Taylor Street
Entity Address, City or Town	Portland
Entity Address, State or Province	OR
Entity Address, Postal Zip Code	97204
City Area Code	(503)
Local Phone Number	226-4211
Title of 12(b) Security	Common Stock
Trading Symbol	NWN
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		35,099,161
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Central Index Key	0001733998
Northwest Natural Gas Company [Member]
Document Information [Line Items]
Document Type	10-Q
Document Period End Date	Sep. 30, 2022
Entity Registrant Name	NORTHWEST NATURAL GAS COMPANY
Entity File Number	1-15973
Entity Incorporation, State or Country Code	OR
Entity Tax Identification Number	93-0256722
Entity Address, Address Line One	250 SW Taylor Street
Entity Address, City or Town	Portland
Entity Address, State or Province	OR
Entity Address, Postal Zip Code	97204
City Area Code	(503)
Local Phone Number	226-4211
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Central Index Key	0000073020

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Operating revenues [Abstract]
Operating revenues	$ 116,839	$ 101,447	$ 662,100	$ 566,310
Operating expenses:
Cost of gas	36,105	25,266	261,413	178,669
Operations and maintenance	50,745	47,329	161,405	149,567
Environmental remediation	980	806	7,950	6,092
General taxes	9,572	9,061	30,665	29,344
Revenue taxes	4,437	3,891	26,037	22,226
Depreciation	29,026	28,438	85,565	84,679
Other operating expenses	901	1,047	2,815	2,794
Total operating expenses	131,766	115,838	575,850	473,371
Income from operations	(14,927)	(14,391)	86,250	92,939
Other income (expense), net	1,636	(2,216)	908	(8,355)
Interest expense, net	13,054	11,175	36,156	33,329
Income (loss) before income taxes	(26,345)	(27,782)	51,002	51,255
Income tax expense (benefit)	(6,758)	(7,127)	12,635	13,117
Net income (loss)	(19,587)	(20,655)	38,367	38,138
Other comprehensive income (loss):
Amortization of non-qualified employee benefit plan liability, net of taxes	202	234	596	676
Comprehensive income (loss)	(19,385)	(20,421)	38,963	38,814
Supplemental Income Statement Elements [Abstract]
Amortization of non-qualified employee benefit plan liability, tax	$ 73	$ 80	$ 215	$ 240
Average common shares outstanding:
Basic (in shares)	34,939	30,696	33,491	30,659
Diluted (in shares)	34,939	30,696	33,539	30,708
Earnings per share of common stock:
Basic (in dollars per share)	$ (0.56)	$ (0.67)	$ 1.15	$ 1.24
Diluted (in dollars per share)	$ (0.56)	$ (0.67)	$ 1.14	$ 1.24
Northwest Natural Gas Company [Member]
Operating revenues [Abstract]
Operating revenues	$ 110,426	$ 96,036	$ 647,301	$ 552,965
Operating expenses:
Cost of gas	36,164	25,322	261,584	178,837
Operations and maintenance	45,858	43,768	148,614	137,894
Environmental remediation	980	806	7,950	6,092
General taxes	9,467	8,999	30,328	29,041
Revenue taxes	4,375	3,838	25,907	22,143
Depreciation	28,201	27,719	83,166	82,418
Other operating expenses	675	669	2,370	2,368
Total operating expenses	125,720	111,121	559,919	458,793
Income from operations	(15,294)	(15,085)	87,382	94,172
Other income (expense), net	1,161	(2,295)	197	(8,526)
Interest expense, net	11,128	10,850	32,558	32,336
Income (loss) before income taxes	(25,261)	(28,230)	55,021	53,310
Income tax expense (benefit)	(6,455)	(7,212)	13,678	13,628
Net income (loss)	(18,806)	(21,018)	41,343	39,682
Other comprehensive income (loss):
Amortization of non-qualified employee benefit plan liability, net of taxes	202	234	596	676
Comprehensive income (loss)	(18,604)	(20,784)	41,939	40,358
Supplemental Income Statement Elements [Abstract]
Amortization of non-qualified employee benefit plan liability, tax	$ 73	$ 80	$ 215	$ 240

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021	Sep. 30, 2021
Current assets:
Cash and cash equivalents	$ 108,556	$ 18,559	$ 19,502
Accounts receivable	50,850	101,495	39,209
Accrued unbilled revenue	16,857	82,169	16,809
Allowance for uncollectible accounts	(2,171)	(2,018)	(2,702)
Regulatory assets	104,830	72,391	80,638
Derivative instruments	62,710	48,130	105,175
Inventories	98,725	57,262	59,997
Other current assets	41,414	59,288	39,551
Total current assets	481,771	437,276	358,179
Non-current assets:
Property, plant, and equipment	4,207,328	3,997,243	3,919,096
Less: Accumulated depreciation	1,166,150	1,125,873	1,112,734
Total property, plant, and equipment, net	3,041,178	2,871,370	2,806,362
Regulatory assets	301,660	314,579	325,071
Derivative instruments	8,008	10,730	24,555
Other investments	96,569	89,278	76,027
Operating lease right of use asset, net	73,145	75,049	75,634
Assets under sales-type leases	135,480	138,995	140,189
Goodwill	74,732	70,570	69,789
Other non-current assets	88,169	56,757	53,419
Total non-current assets	3,818,941	3,627,328	3,571,046
Total assets	4,300,712	4,064,604	3,929,225
Current liabilities:
Short-term debt	141,000	389,500	399,500
Current maturities of long-term debt	50,614	345	278
Accounts payable	118,274	133,486	94,897
Taxes accrued	18,080	15,520	16,558
Interest accrued	11,086	7,503	9,315
Regulatory liabilities	111,551	112,281	164,168
Derivative instruments	19,594	10,402	9,818
Operating lease liabilities	1,361	1,296	1,213
Other current liabilities	39,796	54,432	39,218
Total current liabilities	511,356	724,765	734,965
Long-term debt	1,287,006	1,044,587	916,026
Deferred credits and other non-current liabilities:
Deferred tax liabilities	349,633	340,231	323,925
Regulatory liabilities	663,547	658,332	665,390
Pension and other postretirement benefit liabilities	160,196	166,684	202,287
Derivative instruments	18,824	412	268
Operating lease liabilities	78,469	79,468	79,789
Other non-current liabilities	110,825	114,979	115,114
Total deferred credits and other non-current liabilities	1,381,494	1,360,106	1,386,773
Commitments and contingencies (Note 16)
Equity:
Common stock	$ 786,094	$ 590,771	$ 573,578
Shares Authorized (in shares)	100,000,000	100,000,000	100,000,000
Shares outstanding (in shares)	35,098,000	31,129,000	30,730,000
Shares issued (in shares)	35,098,000	31,129,000	30,730,000
Par Value (in dollars per share)	$ 0	$ 0	$ 0
Retained earnings	$ 345,570	$ 355,779	$ 330,109
Accumulated other comprehensive loss	(10,808)	(11,404)	(12,226)
Total equity	1,120,856	935,146	891,461
Total liabilities and equity	4,300,712	4,064,604	3,929,225
Northwest Natural Gas Company [Member]
Current assets:
Cash and cash equivalents	11,386	12,271	9,697
Accounts receivable	48,082	99,780	37,328
Accrued unbilled revenue	16,649	82,028	16,702
Receivables from affiliates	221	261	628
Allowance for uncollectible accounts	(2,114)	(1,962)	(2,658)
Regulatory assets	104,830	72,391	80,638
Derivative instruments	62,710	48,130	105,175
Inventories	97,633	56,752	59,641
Other current assets	32,605	47,378	29,075
Total current assets	372,002	417,029	336,226
Non-current assets:
Property, plant, and equipment	4,124,488	3,931,640	3,857,652
Less: Accumulated depreciation	1,157,400	1,119,361	1,106,901
Total property, plant, and equipment, net	2,967,088	2,812,279	2,750,751
Regulatory assets	301,596	314,539	325,031
Derivative instruments	8,008	10,730	24,555
Other investments	80,871	74,786	75,991
Operating lease right of use asset, net	73,046	74,987	75,565
Assets under sales-type leases	135,480	138,995	140,189
Other non-current assets	86,661	55,027	52,653
Total non-current assets	3,652,750	3,481,343	3,444,735
Total assets	4,024,752	3,898,372	3,780,961
Current liabilities:
Short-term debt	53,000	245,500	370,500
Current maturities of long-term debt	49,938	0	0
Accounts payable	115,066	131,475	91,947
Payables to affiliates	1,789	1,248	2,568
Taxes accrued	17,914	15,476	16,472
Interest accrued	10,533	7,296	9,258
Regulatory liabilities	111,526	112,281	164,168
Derivative instruments	19,594	10,402	9,818
Operating lease liabilities	1,298	1,273	1,184
Other current liabilities	38,998	53,591	38,642
Total current liabilities	419,656	578,542	704,557
Long-term debt	1,076,533	986,495	857,760
Deferred credits and other non-current liabilities:
Deferred tax liabilities	346,423	337,717	321,636
Regulatory liabilities	662,565	657,350	664,521
Pension and other postretirement benefit liabilities	160,196	166,684	202,287
Derivative instruments	18,824	412	268
Operating lease liabilities	78,436	79,431	79,752
Other non-current liabilities	109,304	113,934	114,438
Total deferred credits and other non-current liabilities	1,375,748	1,355,528	1,382,902
Commitments and contingencies (Note 16)
Equity:
Common stock	614,903	435,515	321,641
Retained earnings	548,720	553,696	526,327
Accumulated other comprehensive loss	(10,808)	(11,404)	(12,226)
Total equity	1,152,815	977,807	835,742
Total liabilities and equity	$ 4,024,752	$ 3,898,372	$ 3,780,961

Consolidated Statement of Share

Consolidated Statement of Shareholders' Equity - USD ($) $ in Thousands	Total	Northwest Natural Gas Company [Member]	Common Stock Including APIC [Member]	Common Stock Including APIC [Member] Northwest Natural Gas Company [Member]	Retained Earnings [Member]	Retained Earnings [Member] Northwest Natural Gas Company [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Other Comprehensive Income (Loss) [Member] Northwest Natural Gas Company [Member]
Beginning Balance at Dec. 31, 2020	$ 888,733	$ 835,184	$ 565,112	$ 319,506	$ 336,523	$ 528,580	$ (12,902)	$ (12,902)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Capital contributions from parent		2,135		2,135
Net income	38,138	39,682			38,138	39,682
Dividends on common stock					(44,552)	(41,935)
Other comprehensive income	38,814	40,358					676	676
Stock-based compensation			2,973
Shares issued pursuant to equity based plans, net of shares withheld for taxes			3,386
Issuances of common stock, net of issuance costs			2,107
Ending Balance at Sep. 30, 2021	$ 891,461	835,742	573,578	321,641	330,109	526,327	(12,226)	(12,226)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends per share of common stock	$ 1.4400
Beginning Balance at Jun. 30, 2021	$ 922,826	868,391	569,785	319,506	365,501	561,345	(12,460)	(12,460)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Capital contributions from parent				2,135
Net income	(20,655)	(21,018)			(20,655)	(21,018)
Dividends on common stock					(14,737)	(14,000)
Other comprehensive income	(20,421)	(20,784)					234	234
Stock-based compensation			527
Shares issued pursuant to equity based plans, net of shares withheld for taxes			1,159
Issuances of common stock, net of issuance costs			2,107
Ending Balance at Sep. 30, 2021	$ 891,461	835,742	573,578	321,641	330,109	526,327	(12,226)	(12,226)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends per share of common stock	$ 0.4800
Beginning Balance at Dec. 31, 2021	$ 935,146	977,807	590,771	435,515	355,779	553,696	(11,404)	(11,404)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Capital contributions from parent		179,388		179,388
Net income	38,367	41,343			38,367	41,343
Dividends on common stock					(48,576)	(46,319)
Other comprehensive income	38,963	41,939					596	596
Stock-based compensation			2,695
Shares issued pursuant to equity based plans, net of shares withheld for taxes			1,958
Issuances of common stock, net of issuance costs			190,670
Ending Balance at Sep. 30, 2022	$ 1,120,856	1,152,815	786,094	614,903	345,570	548,720	(10,808)	(10,808)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends per share of common stock	$ 1.4475
Beginning Balance at Jun. 30, 2022	$ 1,138,779	1,173,676	767,826	601,032	381,963	583,654	(11,010)	(11,010)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Capital contributions from parent				13,871
Net income	(19,587)	(18,806)			(19,587)	(18,806)
Dividends on common stock					(16,806)	(16,128)
Other comprehensive income	(19,385)	(18,604)					202	202
Stock-based compensation			463
Shares issued pursuant to equity based plans, net of shares withheld for taxes			954
Issuances of common stock, net of issuance costs			16,851
Ending Balance at Sep. 30, 2022	$ 1,120,856	$ 1,152,815	$ 786,094	$ 614,903	$ 345,570	$ 548,720	$ (10,808)	$ (10,808)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends per share of common stock	$ 0.4825

Consolidated Statement of Cash

Consolidated Statement of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Operating activities:
Net income	$ 38,367	$ 38,138
Adjustments to reconcile net income to cash provided by operations:
Depreciation	85,565	84,679
Regulatory amortization of gas reserves	4,527	11,606
Deferred income taxes	7,759	2,748
Qualified defined benefit pension plan expense	4,013	12,075
Contributions to qualified defined benefit pension plans	0	(9,590)
Deferred environmental expenditures, net	(14,437)	(14,952)
Environmental remediation expense	7,950	6,092
Asset optimization revenue sharing bill credits	(41,102)	(9,053)
Other	16,640	14,868
Changes in assets and liabilities:
Receivables, net	114,755	83,826
Inventories	(41,463)	(17,307)
Income and other taxes	19,447	19,620
Accounts payable	(30,010)	(18,057)
Deferred gas costs	(1,785)	(33,379)
Asset optimization revenue sharing	17,629	41,407
Decoupling mechanism	7,124	(9,172)
Change in Cloud-based software Assets	(17,332)	(6,851)
Other, net	(11,686)	(14,974)
Cash provided by operating activities	165,961	181,724
Investing activities:
Capital expenditures	(251,842)	(212,376)
Acquisitions, net of cash acquired	(2,352)	(375)
Proceeds from the sale of assets	539	2,712
Proceeds from Sale of Equity Method Investments	0	7,000
Other	(3,349)	(482)
Cash used in investing activities	(257,004)	(203,521)
Financing activities:
Proceeds from common stock issued, net	190,929	2,107
Long-term debt issued	290,000	55,000
Long-term debt retired	0	(95,000)
Proceeds from term loan due within one year	0	100,000
Repayment of commercial paper, maturities greater than three months	0	(195,025)
Changes in other short-term debt, net	(248,500)	190,000
Cash dividend payments on common stock	(46,434)	(41,827)
Other	(1,802)	(1,240)
Cash used in financing activities	184,193	14,015
Cash, cash equivalents and restricted cash	120,270	27,672
Increase (decrease) in cash, cash equivalents and restricted cash	93,150	(7,782)
Supplemental disclosure of cash flow information:
Interest paid, net of capitalization	31,774	30,910
Income taxes paid, net of refunds	2,106	6,980
Northwest Natural Gas Company [Member]
Operating activities:
Net income	41,343	39,682
Adjustments to reconcile net income to cash provided by operations:
Depreciation	83,166	82,418
Regulatory amortization of gas reserves	4,527	11,606
Deferred income taxes	7,013	1,687
Qualified defined benefit pension plan expense	4,013	12,075
Contributions to qualified defined benefit pension plans	0	(9,590)
Deferred environmental expenditures, net	(14,437)	(14,952)
Environmental remediation expense	7,950	6,092
Asset optimization revenue sharing bill credits	(41,102)	(9,053)
Other	16,665	13,728
Changes in assets and liabilities:
Receivables, net	115,915	84,726
Inventories	(40,881)	(17,317)
Income and other taxes	17,412	5,175
Accounts payable	(32,023)	(22,929)
Deferred gas costs	(1,785)	(33,379)
Asset optimization revenue sharing	17,629	41,407
Decoupling mechanism	7,124	(9,172)
Change in Cloud-based software Assets	(17,332)	(6,851)
Other, net	(12,604)	(13,525)
Cash provided by operating activities	162,593	161,828
Investing activities:
Capital expenditures	(236,467)	(199,399)
Proceeds from the sale of assets	539	2,712
Other	(3,349)	(482)
Cash used in investing activities	(239,277)	(197,169)
Financing activities:
Capital contributions from parent	179,388	2,135
Long-term debt issued	140,000	0
Long-term debt retired	0	(60,000)
Proceeds from term loan due within one year	0	100,000
Repayment of commercial paper, maturities greater than three months	0	(195,025)
Changes in other short-term debt, net	(192,500)	234,000
Cash dividend payments on common stock	(46,319)	(41,935)
Other	(1,617)	(1,706)
Cash used in financing activities	78,952	37,469
Cash, cash equivalents and restricted cash	23,100	17,867
Increase (decrease) in cash, cash equivalents and restricted cash	2,268	2,128
Supplemental disclosure of cash flow information:
Interest paid, net of capitalization	28,326	29,920
Income taxes paid, net of refunds	$ 5,990	$ 23,035

Organization and Principles of

Organization and Principles of Consolidation	9 Months Ended
	Sep. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Principles of Consolidation	ORGANIZATION AND PRINCIPLES OF CONSOLIDATION The accompanying consolidated financial statements represent the respective, consolidated financial results of Northwest Natural Holding Company (NW Holdings) and Northwest Natural Gas Company (NW Natural) and all respective companies that each registrant directly or indirectly controls, either through majority ownership or otherwise. This is a combined report of NW Holdings and NW Natural, which includes separate consolidated financial statements for each registrant. NW Natural's regulated natural gas distribution activities are reported in the natural gas distribution (NGD) segment. The NGD segment is NW Natural's core operating business and serves residential, commercial, and industrial customers in Oregon and southwest Washington. The NGD segment is the only reportable segment for NW Holdings and NW Natural. All other activities, water businesses, and other investments are aggregated and reported as other at their respective registrant. NW Holdings and NW Natural consolidate all entities in which they have a controlling financial interest. Investments in corporate joint ventures and partnerships that NW Holdings does not directly or indirectly control, and for which it is not the primary beneficiary, include NNG Financial's investment in Kelso-Beaver Pipeline and NWN Water's investment in Avion Water Company, Inc., which are accounted for under the equity method. NW Natural RNG Holding Company, LLC holds an investment in Lexington Renewable Energy, LLC, which is also accounted for under the equity method. See Note 13 for activity related to equity method investments. NW Holdings and its direct and indirect subsidiaries are collectively referred to herein as NW Holdings, and NW Natural and its direct and indirect subsidiaries are collectively referred to herein as NW Natural. The consolidated financial statements of NW Holdings and NW Natural are presented after elimination of all intercompany balances and transactions. Information presented in these interim consolidated financial statements is unaudited, but includes all material adjustments management considers necessary for a fair statement of the results for each period reported including normal recurring accruals. These consolidated financial statements should be read in conjunction with the audited consolidated financial statements and related notes included in NW Holdings' and NW Natural's combined 2021 Annual Report on Form 10-K (2021 Form 10-K). A significant part of NW Holdings' and NW Natural's business is of a seasonal nature; therefore, NW Holdings and NW Natural results of operations for interim periods are not necessarily indicative of full year results. Seasonality affects the comparability of the results of other operations across quarters but not across years. Notes to the consolidated financial statements reflect the activity for both NW Holdings and NW Natural for all periods presented, unless otherwise noted. Certain reclassifications have been made to conform prior period information to the current presentation. The reclassifications did not have a material effect on our consolidated financial statements.

Significant Accounting Policies

Significant Accounting Policies	9 Months Ended
	Sep. 30, 2022
Accounting Policies [Abstract]
Significant Accounting Policies	SIGNIFICANT ACCOUNTING POLICIES Significant accounting policies are described in Note 2 of the 2021 Form 10-K. There were no material changes to those accounting policies during the nine months ended September 30, 2022 other than those set forth in this Note 2. The following are current updates to certain critical accounting policy estimates and new accounting standards. Industry Regulation In applying regulatory accounting principles, NW Holdings and NW Natural capitalize or defer certain costs and revenues as regulatory assets and liabilities pursuant to orders of the Oregon Public Utilities Commission (OPUC), Washington Utilities and Transportation Commission (WUTC), Idaho Public Utilities Commission (IPUC) or Public Utility Commission of Texas (PUCT), as applicable, which provide for the recovery of revenues or expenses from, or refunds to, utility customers in future periods, including a return or a carrying charge in certain cases. Amounts deferred as regulatory assets and liabilities for NW Holdings and NW Natural were as follows: Regulatory Assets September 30, December 31, In thousands 2022 2021 2021 NW Natural: Current: Unrealized loss on derivatives (1) $ 19,594 $ 9,818 $ 10,402 Gas costs 52,115 39,622 35,641 Environmental costs (2) 9,461 7,068 6,694 Decoupling (3) 114 1,628 969 Pension balancing (4) 7,131 7,131 7,131 Income taxes 2,399 2,939 2,568 Other (5) 14,016 12,432 8,986 Total current $ 104,830 $ 80,638 $ 72,391 Non-current: Unrealized loss on derivatives (1) $ 18,824 $ 268 $ 412 Pension balancing (4) 34,928 40,176 38,302 Income taxes 11,168 13,912 12,609 Pension and other postretirement benefit liabilities 107,722 155,077 116,440 Environmental costs (2) 82,667 83,969 94,636 Gas costs 3,369 2,858 15,477 Decoupling (3) — 118 — Other (5) 42,918 28,653 36,663 Total non-current $ 301,596 $ 325,031 $ 314,539 Other (NW Holdings) 64 40 40 Total non-current - NW Holdings $ 301,660 $ 325,071 $ 314,579 Regulatory Liabilities September 30, December 31, In thousands 2022 2021 2021 NW Natural: Current: Gas costs $ 944 $ 847 $ 70 Unrealized gain on derivatives (1) 62,882 105,175 48,130 Decoupling (3) 13,272 4,484 4,475 Income taxes 7,318 8,217 8,192 Asset optimization revenue sharing 23,461 43,883 45,124 Other (5) 3,649 1,562 6,290 Total current - NW Natural $ 111,526 $ 164,168 $ 112,281 Other (NW Holdings) 25 — — Total current - NW Holdings $ 111,551 $ 164,168 $ 112,281 Non-current: Gas costs $ 50 $ — $ 250 Unrealized gain on derivatives (1) 8,008 24,555 10,730 Decoupling (3) 884 214 3,412 Income taxes (6) 179,319 186,429 181,404 Accrued asset removal costs (7) 460,666 440,410 445,952 Asset optimization revenue sharing — — 1,810 Other (5) 13,638 12,913 13,792 Total non-current - NW Natural $ 662,565 $ 664,521 $ 657,350 Other (NW Holdings) 982 869 982 Total non-current - NW Holdings $ 663,547 $ 665,390 $ 658,332 (1) Unrealized gains or losses on derivatives are non-cash items and therefore do not earn a rate of return or a carrying charge. These amounts are recoverable through NGD rates as part of the annual Purchased Gas Adjustment (PGA) mechanism when realized at settlement. (2) Refer to the Environmental Cost Deferral and Recovery table in Note 16 for a description of environmental costs. (3) This deferral represents the margin adjustment resulting from differences between actual and expected volumes. (4) Balance represents deferred net periodic benefit costs as approved by the OPUC. (5) Balances consist of deferrals and amortizations under approved regulatory mechanisms and typically earn a rate of return or carrying charge. (6) Balance represents excess deferred income tax benefits subject to regulatory flow-through. (7) Estimated costs of removal on certain regulated properties are collected through rates. We believe all costs incurred and deferred at September 30, 2022 are prudent. All regulatory assets and liabilities are reviewed annually for recoverability, or more often if circumstances warrant. If we should determine that all or a portion of these regulatory assets or liabilities no longer meet the criteria for continued application of regulatory accounting, then NW Holdings and NW Natural would be required to write-off the net unrecoverable balances in the period such determination is made. Supplemental Cash Flow Information Restricted cash is primarily comprised of funds from public purpose charges for programs that assist low-income customers with bill payments or energy efficiency. The following table provides a reconciliation of the cash, cash equivalents and restricted cash balances at NW Holdings as of September 30, 2022 and 2021 and December 31, 2021: September 30, December 31, In thousands 2022 2021 2021 Cash and cash equivalents $ 108,556 $ 19,502 $ 18,559 Restricted cash included in other current assets 11,714 8,170 8,561 Cash, cash equivalents and restricted cash $ 120,270 $ 27,672 $ 27,120 The following table provides a reconciliation of the cash, cash equivalents and restricted cash balances at NW Natural as of September 30, 2022 and 2021 and December 31, 2021: September 30, December 31, In thousands 2022 2021 2021 Cash and cash equivalents $ 11,386 $ 9,697 $ 12,271 Restricted cash included in other current assets 11,714 8,170 8,561 Cash, cash equivalents and restricted cash $ 23,100 $ 17,867 $ 20,832 Accounts Receivable and Allowance for Uncollectible Accounts Accounts receivable consist primarily of amounts due for natural gas sales and transportation services to NGD customers, plus amounts due for gas storage services. NW Holdings and NW Natural establish allowances for uncollectible accounts (allowance) for trade receivables, including accrued unbilled revenue, based on the aging of receivables, collection experience of past due account balances including payment plans, and historical trends of write-offs as a percent of revenues. A specific allowance is established and recorded for large individual customer receivables when amounts are identified as unlikely to be partially or fully recovered. Inactive accounts are written-off against the allowance after they are 120 days past due or when deemed uncollectible. Differences between the estimated allowance and actual write-offs will occur based on a number of factors, including changes in economic conditions, customer creditworthiness, and natural gas prices. The allowance for uncollectible accounts is adjusted quarterly, as necessary, based on information currently available. Allowance for Trade Receivables The payment term of our NGD receivables is generally 15 days. For these short-term receivables, it is not expected that forecasted economic conditions would significantly affect the loss estimates under stable economic conditions. For extreme situations like a financial crisis, natural disaster, and the economic slowdown caused by the COVID-19 pandemic, we enhanced our review and analysis. For the third quarter 2022 residential and commercial uncollectible provision, we primarily followed our standard methodology, which includes assessing historical write-off trends and current information on delinquent accounts. Beginning October 1, 2022, new collection rules from the OPUC applied to residential and commercial customers. This included enhanced protections for low-income customers, a return to pre-pandemic time payment arrangements terms, revised disconnection rules during the heating season, and other items. As a result of these Oregon rule changes and our recent collection process experience, we augmented our provision review in the third quarter for Oregon accounts in the following categories: closed or inactive accounts aged less than 120 days, accounts on 24-month payment plans, and all other open accounts not on payment plans. For industrial accounts, we continue to assess the provision on an account-by-account basis with specific reserves taken as necessary. We'll continue to closely monitor and evaluate our accounts receivable and the provision for uncollectible accounts. The following table presents the activity related to the NW Holdings provision for uncollectible accounts by pool, substantially all of which is related to NW Natural's accounts receivable: As of As of December 31, 2021 Nine Months Ended September 30, 2022 September 30, 2022 In thousands Beginning Balance Provision recorded, net of adjustments Write-offs recognized, net of recoveries Ending Balance Allowance for uncollectible accounts: Residential $ 1,460 $ 896 $ (871) $ 1,485 Commercial 178 375 (272) 281 Industrial 67 173 (62) 178 Accrued unbilled and other 313 84 (170) 227 Total $ 2,018 $ 1,528 $ (1,375) $ 2,171 Allowance for Net Investments in Sales-Type Leases NW Natural currently holds two net investments in sales-type leases, with substantially all of the net investment balance related to the North Mist natural gas storage agreement with Portland General Electric (PGE) which is billed under an OPUC-approved rate schedule. See Note 7 for more information on the North Mist lease. Due to the nature of this service, PGE may recover the costs of the lease through general rate cases. Therefore, we expect the risk of loss due to the credit of this lessee to be remote. As such, no allowance for uncollectibility was recorded for our sales-type lease receivables. NW Natural will continue monitoring the credit health of the lessees and the overall economic environment, including the economic factors closely tied to the financial health of our current and future lessees. COVID-19 Impact During 2020, our regulated utilities received approval in their respective jurisdictions to defer certain financial impacts associated with COVID-19 such as bad debt expense, financing costs to secure liquidity, lost revenues related to late fees and reconnection fees, and other COVID-19 related costs, net of offsetting direct expense reductions associated with COVID-19. As of September 30, 2022 and 2021, we had a regulatory asset of approximately $15.1 million and $7.4 million, respectively, for incurred costs associated with COVID-19 that we believe are recoverable. As part of the 2022 Oregon general rate case, we received approval from the OPUC to recover the 2020 and 2021 COVID-19 deferral totaling $10.9 million over two Cloud Computing Arrangements (CCA) Implementation costs associated with its CCA are capitalized consistent with costs capitalized for internal-use software. Capitalized CCA implementation costs are included in other assets in the consolidated balance sheets. The CCA implementation costs are amortized over the term of the related hosting agreement, including renewal periods that are reasonably certain to be exercised. Amortization expense of CCA implementation costs are recorded as operations and maintenance expenses in the consolidated statements of comprehensive income. The CCA implementation costs are included within operating activities in the consolidated statements of cash flows. New Accounting Standards NW Natural and NW Holdings consider the applicability and impact of all accounting standards updates (ASUs) issued by the Financial Accounting Standards Board (FASB). ASUs not listed below were assessed and determined to be either not applicable or are expected to have minimal impact on consolidated financial position or results of operations. Recently Adopted Accounting Pronouncements

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2022
Earnings Per Share [Abstract]
Earnings Per Share	EARNINGS PER SHARE Basic earnings or loss per share are computed using NW Holdings' net income or loss and the weighted average number of common shares outstanding for each period presented. Diluted earnings per share are computed in the same manner, except using the weighted average number of common shares outstanding plus the effects of the assumed exercise of stock options and the payment of estimated stock awards from other stock-based compensation plans that are outstanding at the end of each period presented. Anti-dilutive stock awards are excluded from the calculation of diluted earnings or loss per common share. NW Holdings' diluted earnings or loss per share are calculated as follows: Three Months Ended September 30, Nine Months Ended September 30, In thousands, except per share data 2022 2021 2022 2021 Net income (loss) (19,587) (20,655) 38,367 38,138 Average common shares outstanding - basic 34,939 30,696 33,491 30,659 Additional shares for stock-based compensation plans (See Note 8) — — 48 49 Average common shares outstanding - diluted 34,939 30,696 33,539 30,708 Earnings (loss) per share of common stock: Basic $ (0.56) $ (0.67) $ 1.15 $ 1.24 Diluted $ (0.56) $ (0.67) $ 1.14 $ 1.24 Additional information: Anti-dilutive shares 85 51 — 6

Segment Information

Segment Information	9 Months Ended
	Sep. 30, 2022
Segment Reporting [Abstract]
Segment Information	SEGMENT INFORMATION We primarily operate in one reportable business segment, which is NW Natural's local gas distribution business and is referred to as the NGD s egment. NW Natural and NW Holdings also have investments and b usiness activities not specifically related to the NGD segment, which are aggregated and reported as other and described below for each entity. Natural Gas Distribution NW Natural's local gas distribution segment is a regulated utility principally engaged in the purchase, sale, and delivery of natural gas and related services to customers in Oregon and southwest Washington. In addition to NW Natural's local gas distribution business, the NGD segment also includes the portion of the Mist underground storage facility used to serve NGD customers, the North Mist gas storage expansion in Oregon, NWN Gas Reserves, which is a wholly-owned subsidiary of Energy Corp, and NW Natural RNG Holding Company, LLC, a holding company established to invest in the development and procurement of regulated renewable natural gas for NW Natural. NW Natural NW Natural's activities in Other include Interstate Storage Services and third-party asset management services for the Mist facility in Oregon, appliance retail center operations, and corporate operating and non-operating revenues and expenses that cannot be allocated to NGD operations. Earnings from Interstate Storage Services assets are primarily related to firm storage capacity revenues. Earnings from the Mist facility also include revenue, net of amounts shared with NGD customers, from management of NGD assets at Mist and upstream pipeline capacity when not needed to serve NGD customers. Under the Oregon sharing mechanism, NW Natural retains 80% of the pre-tax income from these services when the costs of the capacity were not included in NGD rates, or 10% of the pre-tax income when the costs have been included in these rates. The remaining 20% and 90%, respectively, are recorded to a deferred regulatory account for crediting back to NGD customers. NW Holdings NW Holdings' activities in Other include all remaining activities not associated with NW Natural, specifically: NWN Water, which consolidates the water and wastewater utility operations and is pursuing other investments in the water sector through itself and wholly-owned subsidiaries; NWN Water's equity investment in Avion Water Company, Inc. ; NWN Gas Storage, a wholly-owned subsidiary of NWN Energ y; other pipeline assets in NNG Financial; and NW Natural Renewables Holdings, LLC and its non-regulated renewable natural gas activities . Other a lso includes corporate revenues and expenses that cannot be allocated to other operations, including certain business development activities . Segment Information Summary Inter-segment transactions were immaterial for the periods presented. The following table presents summary financial information concerning the reportable segment and other. Three Months Ended September 30, In thousands NGD Other NW Natural Other NW Holdings 2022 Operating revenues $ 103,295 $ 7,131 $ 110,426 $ 6,413 $ 116,839 Depreciation 27,937 264 28,201 825 29,026 Income (loss) from operations (20,910) 5,616 (15,294) 367 (14,927) Net income (loss) (23,016) 4,210 (18,806) (781) (19,587) Capital expenditures 79,847 431 80,278 3,868 84,146 2021 Operating revenues $ 91,042 $ 4,994 $ 96,036 $ 5,411 $ 101,447 Depreciation 27,462 257 27,719 719 28,438 Income (loss) from operations (18,288) 3,203 (15,085) 694 (14,391) Net income (loss) (23,297) 2,279 (21,018) 363 (20,655) Capital expenditures 72,822 1,410 74,232 8,036 82,268 Nine Months Ended September 30, In thousands NGD Other NW Natural Other NW Holdings 2022 Operating revenues $ 629,327 $ 17,974 $ 647,301 $ 14,799 $ 662,100 Depreciation 82,372 794 83,166 2,399 85,565 Income (loss) from operations 75,328 12,054 87,382 (1,132) 86,250 Net income (loss) 32,531 8,812 41,343 (2,976) 38,367 Capital expenditures 235,249 1,218 236,467 15,375 251,842 Total assets at September 30, 2022 3,968,040 56,712 4,024,752 275,960 4,300,712 2021 Operating revenues $ 531,994 $ 20,971 $ 552,965 $ 13,345 $ 566,310 Depreciation 81,648 770 82,418 2,261 84,679 Income (loss) from operations 79,530 14,642 94,172 (1,233) 92,939 Net income (loss) 29,247 10,435 39,682 (1,544) 38,138 Capital expenditures 197,190 2,209 199,399 12,977 212,376 Total assets at September 30, 2021 3,730,595 50,366 3,780,961 148,264 3,929,225 Total assets at December 31, 2021 3,846,112 52,260 3,898,372 166,232 4,064,604 Natural Gas Distribution Margin NGD margin is the primary financial measure used by the Chief Operating Decision Maker (CODM) , consisting of NGD operating revenues, reduced by the associated cost of gas, environmental remediation expense, and revenue taxes. The cost of gas purchased for NGD customers is generally a pass-through cost in the amount of revenues billed to regulated NGD customers. Environmental remediation expense represents collections received from customers through environmental recovery mechanisms in Oregon and Washington as well as adjustments for the Oregon environmental earnings test when applicable. This is offset by environmental remediation expense presented in operating expenses. Revenue taxes are collected from NGD customers and remitted to taxing authorities. The collections from customers are offset by the expense recognition of the obligation to the taxing authority. By subtracting cost of gas, environmental remediation expense, and revenue taxes from NGD operating revenues, NGD margin provides a key metric used by the CODM in assessing the performance of the NGD segment. The following table presents additional segment information concerning NGD margin: Three Months Ended September 30, Nine Months Ended September 30, In thousands 2022 2021 2022 2021 NGD margin calculation: NGD distribution revenues $ 98,391 $ 86,271 $ 614,605 $ 517,673 Other regulated services 4,904 4,771 14,722 14,321 Total NGD operating revenues 103,295 91,042 629,327 531,994 Less: NGD cost of gas 36,258 25,322 261,678 178,837 Environmental remediation 975 806 7,945 6,092 Revenue taxes 4,375 3,838 25,907 22,143 NGD margin $ 61,687 $ 61,076 $ 333,797 $ 324,922

Equity

Equity	9 Months Ended
	Sep. 30, 2022
Equity [Abstract]
Stockholders' Equity Note Disclosure	COMMON STOCK In August 2021, NW Holdings initiated an at-the-market (ATM) equity program by entering into an equity distribution agreement under which NW Holdings may issue and sell from time to time shares of common stock, no par value, having an aggregate gross sales price of up to $200 million. NW Holdings is under no obligation to offer and sell common stock under the ATM equity program, which expires in August 2024. Any shares of common stock offered under the ATM equity program are registered on NW Holdings’ universal shelf registration statement filed with the SEC. During the three months ended September 30, 2022, NW Holdings issued and sold 327,221 shares of common stock pursuant to the ATM equity program resulting in cash proceeds of $16.7 million, net of fees and commissions paid to agents of $0.3 million. During the nine months ended September 30, 2022, NW Holdings issued and sold 1,005,322 shares of common stock pursuant to the ATM equity program resulting in cash proceeds of $51.9 million, net of fees and commissions paid to agents of $1.0 million. As of September 30, 2022, NW Holdings had $129.2 million of equity available for issuance under the program. The ATM equity program was initiated to raise funds for general corporate purposes, including equity contributions to NW Holdings’ subsidiaries, NW Natural and NW Natural Water. Contributions to NW Natural and NW Natural Water will be used for general corporate purposes. On April 1, 2022, NW Holdings issued and sold 2,875,000 shares of its common stock pursuant to a registration statement on Form S-3 and related prospectus supplement. NW Holdings received net offering proceeds, after deducting the underwriter's discounts and commissions and expenses payable by NW Holdings, of approximately $138.6 million. The proceeds were used for general corporate purposes, including repayment of its short-term indebtedness and/or making equity contributions to NW Holdings' subsidiaries, NW Natural, NW Natural Water and NW Natural Renewables. Contributions to NW Natural, NW Natural Water and NW Natural Renewables are to be used for general corporate purposes. Of the contributions received by NW Natural, $130.0 million was used to repay its short-term indebtedness.

Revenue

Revenue	9 Months Ended
	Sep. 30, 2022
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Customer	REVENUE The following tables present disaggregated revenue: Three Months Ended September 30, In thousands NGD Other NW Natural Other NW Holdings 2022 Natural gas sales $ 95,784 $ — $ 95,784 $ — $ 95,784 Gas storage revenue, net — 2,882 2,882 — 2,882 Asset management revenue, net — 3,047 3,047 — 3,047 Appliance retail center revenue — 1,202 1,202 — 1,202 Other revenue 624 — 624 6,413 7,037 Revenue from contracts with customers 96,408 7,131 103,539 6,413 109,952 Alternative revenue 2,589 — 2,589 — 2,589 Leasing revenue 4,298 — 4,298 — 4,298 Total operating revenues $ 103,295 $ 7,131 $ 110,426 $ 6,413 $ 116,839 2021 Natural gas sales $ 83,947 $ — $ 83,947 $ — $ 83,947 Gas storage revenue, net — 2,794 2,794 — 2,794 Asset management revenue, net — 1,012 1,012 — 1,012 Appliance retail center revenue — 1,188 1,188 — 1,188 Other revenue 403 — 403 5,411 5,814 Revenue from contracts with customers 84,350 4,994 89,344 5,411 94,755 Alternative revenue 2,307 — 2,307 — 2,307 Leasing revenue 4,385 — 4,385 — 4,385 Total operating revenues $ 91,042 $ 4,994 $ 96,036 $ 5,411 $ 101,447 Nine Months Ended September 30, In thousands NGD Other NW Natural Other NW Holdings 2022 Natural gas sales $ 623,121 $ — $ 623,121 $ — $ 623,121 Gas storage revenue, net — 8,678 8,678 — 8,678 Asset management revenue, net — 4,941 4,941 — 4,941 Appliance retail center revenue — 4,355 4,355 — 4,355 Other revenue 1,882 — 1,882 14,799 16,681 Revenue from contracts with customers 625,003 17,974 642,977 14,799 657,776 Alternative revenue (8,571) — (8,571) — (8,571) Leasing revenue 12,895 — 12,895 — 12,895 Total operating revenues $ 629,327 $ 17,974 $ 647,301 $ 14,799 $ 662,100 2021 Natural gas sales $ 503,769 $ — $ 503,769 $ — $ 503,769 Gas storage revenue, net — 8,094 8,094 — 8,094 Asset management revenue, net — 8,757 8,757 — 8,757 Appliance retail center revenue — 4,120 4,120 — 4,120 Other revenue 1,217 — 1,217 13,345 14,562 Revenue from contracts with customers 504,986 20,971 525,957 13,345 539,302 Alternative revenue 13,843 — 13,843 — 13,843 Leasing revenue 13,165 — 13,165 — 13,165 Total operating revenues $ 531,994 $ 20,971 $ 552,965 $ 13,345 $ 566,310 NW Natural's revenue represents substantially all of NW Holdings' revenue and is recognized for both registrants when the obligation to customers is satisfied and in the amount expected to be received in exchange for transferring goods or providing services. Revenue from contracts with customers contains one performance obligation that is generally satisfied over time, using the output method based on time elapsed, due to the continuous nature of the service provided. The transaction price is determined by a set price agreed upon in the contract or dependent on regulatory tariffs. Customer accounts are settled on a monthly basis or paid at time of sale and based on historical experience. It is probable that we will collect substantially all of the consideration to which we are entitled. We evaluated the probability of collection in accordance with the current expected credit losses standard. NW Holdings and NW Natural do not have any material contract assets, as net accounts receivable and accrued unbilled revenue balances are unconditional and only involve the passage of time until such balances are billed and collected. NW Holdings and NW Natural do not have any material contract liabilities. Revenue taxes are included in operating revenues with an equal and offsetting expense recognized in operating expenses in the consolidated statements of comprehensive income. Revenue-based taxes are primarily franchise taxes, which are collected from NGD customers and remitted to taxing authorities. Natural Gas Distribution Natural Gas Sales NW Natural's primary source of revenue is providing natural gas to customers in the NGD service territory, which includes residential, commercial, industrial and transportation customers. NGD revenue is generally recognized over time upon delivery of the gas commodity or service to the customer, and the amount of consideration received and recognized as revenue is dependent on the Oregon and Washington tariffs. Customer accounts are to be paid in full each month, and there is no right of return or warranty for services provided. Revenues include firm and interruptible sales and transportation services, franchise taxes recovered from the customer, late payment fees, service fees, and accruals for gas delivered but not yet billed (accrued unbilled revenue). The accrued unbilled revenue balance is based on estimates of deliveries during the period from the last meter reading and management judgment is required for a number of factors used in this calculation, including customer use and weather factors. We applied the significant financing practical expedient and have not adjusted the consideration NW Natural expects to receive from NGD customers for the effects of a significant financing component as all payment arrangements are settled annually. Due to the election of the right to invoice practical expedient, we do not disclose the value of unsatisfied performance obligations. Alternative Revenue Weather normalization (WARM) and decoupling mechanisms are considered to be alternative revenue programs. Alternative revenue programs are considered to be contracts between NW Natural and its regulator and are excluded from revenue from contracts with customers. Leasing Revenue Leasing revenue primarily consists of revenues from NW Natural's North Mist Storage contract with Portland General Electric (PGE) in support of PGE's gas-fired electric power generation facilities under an initial 30-year contract with options to extend, totaling up to an additional 50 years upon mutual agreement of the parties. The facility is accounted for as a sales-type lease with regulatory accounting deferral treatment. The investment is included in rate base under an established cost-of-service tariff schedule, with revenues recognized according to the tariff schedule and as such, profit upon commencement was deferred and will be amortized over the lease term. Leasing revenue also contains rental revenue from small leases of property owned by NW Natural to third parties. The majority of these transactions are accounted for as operating leases and the revenue is recognized over the term of the lease agreement. Lease revenue is excluded from revenue from contracts with customers. See Note 7 for additional information. NW Natural Other Gas Storage Revenue NW Natural's other revenue includes gas storage activity, which includes Interstate Storage Services used to store natural gas for customers. Gas storage revenue is generally recognized over time as the gas storage service is provided to the customer and the amount of consideration received and recognized as revenue is dependent on set rates defined per the storage agreements. Noncash consideration in the form of dekatherms of natural gas is received as consideration for providing gas injection services to gas storage customers. This noncash consideration is measured at fair value using the average spot rate. Customer accounts are generally paid in full each month, and there is no right of return or warranty for services provided. Revenues include firm and interruptible storage services, net of the profit sharing amount refunded to NGD customers. Asset Management Revenue Revenues include the optimization of third-party storage assets and pipeline capacity and are provided net of the profit sharing amount refunded to NGD customers. Certain asset management revenues received are recognized over time using a straight-line approach over the term of each contract, and the amount of consideration received and recognized as revenue is dependent on a variable pricing model. Variable revenues earned above guaranteed amounts are estimated and recognized at the end of each period using the most likely amount approach. Additionally, other asset management revenues may be based on a fixed rate. Generally, asset management accounts are settled on a monthly basis. As of September 30, 2022, u nrecognized revenue for the fixed component of the transaction price related to gas storage and asset management revenue was approximat ely $84.4 million. Of this amount, approximately $5.3 million will be recognized during the remainder of 2022, $18.6 million in 2023, $15.6 million in 2024, $13.5 million in 2025, $9.4 million in 2026 and $22.0 million thereafter. The amounts presented here are calculated using current contracted rates. Appliance Retail Center Revenue NW Natural owns and operates an appliance store that is open to the public, where customers can purchase natural gas home appliances. Revenue from the sale of appliances is recognized at the point in time in which the appliance is transferred to the third party responsible for delivery and installation services and when the customer has legal title to the appliance. It is required that the sale be paid for in full prior to transfer of legal title. The amount of consideration received and recognized as revenue varies with changes in marketing incentives and discounts offered to customers. NW Holdings Other NW Holdings' primary source of other revenue is providing water and wastewater services to customers. Water and wastewater service revenue is generally recognized over time upon delivery of the water commodity or service to the customer, and the amount of consideration received and recognized as revenue is dependent on the tariffs established in the states we operate. Customer accounts are to be paid in full each month or bi-monthly, and there is no right of return or warranty for services provided. We applied the significant financing practical expedient and have not adjusted the consideration we expect to receive from water distribution and wastewater collection customers for the effects of a significant financing component as all payment arrangements are settled annually. Due to the election of the right to invoice practical expedient, we do not disclose the value of unsatisfied performance obligations.

Leases

Leases	9 Months Ended
	Sep. 30, 2022
Leases [Abstract]
Lessee, Operating Leases	LEASES Lease Revenue Leasing revenue primarily consists of NW Natural's North Mist natural gas storage agreement with Portland General Electric (PGE), which is billed under an OPUC-approved rate schedule and includes an initial 30-year term beginning May 2019 with options to extend, totaling up to an additional 50 years upon mutual agreement of the parties. Under U.S. GAAP, this agreement is classified as a sales-type lease and qualifies for regulatory accounting deferral treatment. The investment in the storage facility is included in rate base under a separately established cost-of-service tariff, with revenues recognized according to the tariff schedule. As such, the selling profit that was calculated upon commencement as part of the sale-type lease recognition was deferred and will be amortized over the lease term. Billing rates under the cost-of-service tariff will be updated annually to reflect current information including depreciable asset levels, forecasted operating expenses, and the results of regulatory proceedings, as applicable, and revenue received under this agreement is recognized as operating revenue on the consolidated statements of comprehensive income. There are no variable payments or residual value guarantees. The lease does not contain an option to purchase the underlying assets. NW Natural also maintains a sales-type lease for specialized compressor facilities to provide high pressure compressed natural gas (CNG) services. Lease payments are outlined in an OPUC-approved rate schedule over a 10-year term. There are no variable payments or residual value guarantees. The selling profit computed upon lease commencement was not significant. Our lessor portfolio also contains small leases of property owned by NW Natural and NW Holdings to third parties. These transactions are accounted for as operating leases and the revenue is recognized over the term of the lease agreement. The components of lease revenue at NW Natural were as follows: Three Months Ended September 30, Nine Months Ended September 30, In thousands 2022 2021 2022 2021 Lease revenue Operating leases $ 19 $ 18 $ 56 $ 61 Sales-type leases 4,279 4,367 12,839 13,104 Total lease revenue $ 4,298 $ 4,385 $ 12,895 $ 13,165 Additionally, lease revenue of $0.3 million and $0.1 million was recognized for the three months ended September 30, 2022 and 2021, respectively, and lease revenue of $0.4 million was recognized for the nine months ended September 30, 2022 and 2021 related to operating leases associated with non-utility property rentals. Lease revenue related to these leases was presented in other income (expense), net on the consolidated statements of comprehensive income as it is non-operating income. Total future minimum lease payments to be received under non-cancelable leases at September 30, 2022 are as follows: In thousands Operating Sales-Type Total NW Natural: Remainder of 2022 $ 145 $ 4,217 $ 4,362 2023 76 16,557 16,633 2024 76 15,867 15,943 2025 67 15,306 15,373 2026 36 14,901 14,937 Thereafter 22 236,820 236,842 Total minimum lease payments $ 422 $ 303,668 $ 304,090 Less: imputed interest 168,188 Total leases receivable $ 135,480 Other (NW Holdings): Remainder of 2022 $ 13 $ — $ 13 2023 51 — 51 2024 52 — 52 2025 53 — 53 2026 56 — 56 Thereafter 914 — 914 Total minimum lease payments $ 1,139 $ — $ 1,139 NW Holdings: Remainder of 2022 $ 158 $ 4,217 $ 4,375 2023 127 16,557 16,684 2024 128 15,867 15,995 2025 120 15,306 15,426 2026 92 14,901 14,993 Thereafter 936 236,820 237,756 Total minimum lease payments $ 1,561 $ 303,668 $ 305,229 Less: imputed interest 168,188 Total leases receivable $ 135,480 The total leases receivable above is reported under the NGD segment and the short- and long-term portions are included within other current assets and assets under sales-type leases on the consolidated balance sheets, respectively. The total amount of unguaranteed residual assets was $5.0 million, $4.6 million and $4.7 million at September 30, 2022 and 2021 and December 31, 2021, respectively, and is included in assets under sales-type leases on the consolidated balance sheets. Additionally, under regulatory accounting, the revenues and expenses associated with these agreements are presented on the consolidated statements of comprehensive income such that their presentation aligns with similar regulated activities at NW Natural. Lease Expense Operating Leases We have operating leases for land, buildings and equipment. Our primary lease is for NW Natural's headquarters and operations center. Our leases have remaining lease terms of 2 months to 18 years. Many of our lease agreements include options to extend the lease, which we do not include in our minimum lease terms unless they are reasonably certain to be exercised. Short-term leases with a term of 12 months or less are not recorded on the balance sheet. As most of our leases do not provide an implicit rate and are entered into by NW Natural, we use an estimated discount rate representing the rate we would have incurred to finance the funds necessary to purchase the leased asset and is based on information available at the lease commencement date in determining the present value of lease payments. The components of lease expense, a portion of which is capitalized, were as follows: Three Months Ended September 30, Nine Months Ended September 30, In thousands 2022 2021 2022 2021 NW Natural: Operating lease expense $ 1,767 $ 1,735 $ 5,235 $ 5,123 Short-term lease expense $ 105 $ 499 $ 684 $ 1,068 Other (NW Holdings): Operating lease expense $ 7 $ 14 $ 22 $ 50 NW Holdings: Operating lease expense $ 1,774 $ 1,749 $ 5,257 $ 5,173 Short-term lease expense $ 105 $ 499 $ 684 $ 1,068 Supplemental balance sheet information related to operating leases as of September 30, 2022 and 2021 and December 31, 2021 is as follows: In thousands September 30, December 31, 2022 2021 2021 NW Natural: Operating lease right of use asset $ 73,046 $ 75,565 $ 74,987 Operating lease liabilities - current liabilities $ 1,298 $ 1,184 $ 1,273 Operating lease liabilities - non-current liabilities 78,436 79,752 79,431 Total operating lease liabilities $ 79,734 $ 80,936 $ 80,704 Other (NW Holdings): Operating lease right of use asset $ 99 $ 69 $ 62 Operating lease liabilities - current liabilities $ 63 $ 29 $ 23 Operating lease liabilities - non-current liabilities 33 37 37 Total operating lease liabilities $ 96 $ 66 $ 60 NW Holdings: Operating lease right of use asset $ 73,145 $ 75,634 $ 75,049 Operating lease liabilities - current liabilities $ 1,361 $ 1,213 $ 1,296 Operating lease liabilities - non-current liabilities 78,469 79,789 79,468 Total operating lease liabilities $ 79,830 $ 81,002 $ 80,764 The weighted-average remaining lease terms and weighted-average discount rates for the operating leases at NW Natural were as follows: In thousands September 30, December 31, 2022 2021 2021 Weighted-average remaining lease term (years) 17.5 18.4 18.2 Weighted-average discount rate 7.3 % 7.2 % 7.2 % Headquarters and Operations Center Lease NW Natural commenced a 20-year operating lease agreement in March 2020 for a new headquarters and operations center in Portland, Oregon. There is an option to extend the term of the lease for two additional periods of seven years. There is a material timing difference between the minimum lease payments and expense recognition as calculated under operating lease accounting rules. OPUC issued an order allowing us to align our expense recognition with cash payments for ratemaking purposes. We recorded the difference between the minimum lease payments and the aggregate of the imputed interest on the finance lease obligation and amortization of the right-of-use asset as a deferred regulatory asset on our balance sheet. The balance of the regulatory asset was $6.6 million, $5.3 million and $5.7 million as of September 30, 2022 and 2021 and December 31, 2021, respectively. Maturities of operating lease liabilities at September 30, 2022 were as follows: In thousands NW Natural Other NW Holdings Remainder of 2022 $ 1,752 $ 8 $ 1,760 2023 7,046 26 7,072 2024 7,183 27 7,210 2025 7,185 20 7,205 2026 7,353 6 7,359 Thereafter 116,431 18 116,449 Total lease payments 146,950 105 147,055 Less: imputed interest 67,216 9 67,225 Total lease obligations 79,734 96 79,830 Less: current obligations 1,298 63 1,361 Long-term lease obligations $ 78,436 $ 33 $ 78,469 As of September 30, 2022, there were no finance lease liabilities at NW Natural. Supplemental cash flow information related to leases was as follows: Three Months Ended September 30, Nine Months Ended September 30, In thousands 2022 2021 2022 2021 NW Natural: Cash paid for amounts included in the measurement of lease liabilities Operating cash flows from operating leases $ 1,759 $ 1,727 $ 5,225 $ 5,113 Finance cash flows from finance leases $ 92 $ 123 $ 474 $ 801 Right of use assets obtained in exchange for lease obligations Operating leases $ — $ — $ — $ 154 Finance leases $ 6 $ 75 $ 226 $ 169 Other (NW Holdings): Cash paid for amounts included in the measurement of lease liabilities Operating cash flows from operating leases $ 12 $ 18 $ 24 $ 51 Right of use assets obtained in exchange for lease obligations Operating leases $ 61 $ — $ 61 $ — NW Holdings: Cash paid for amounts included in the measurement of lease liabilities Operating cash flows from operating leases $ 1,771 $ 1,745 $ 5,249 $ 5,164 Finance cash flows from finance leases $ 92 $ 123 $ 474 $ 801 Right of use assets obtained in exchange for lease obligations Operating leases $ 61 $ — $ 61 $ 154 Finance leases $ 6 $ 75 $ 226 $ 169 Finance Leases

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2022
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation	STOCK-BASED COMPENSATION Stock-based compensation plans are designed to promote stock ownership in NW Holdings by employees, including officers. These compensation plans include a Long Term Incentive Plan (LTIP) and an Employee Stock Purchase Plan (ESPP). For additional information on stock-based compensation plans, see Note 8 in the 2021 Form 10-K and the updates provided below. Long Term Incentive Plan Performance Shares LTIP performance shares incorporate a combination of market, performance, and service-based factors. During the nine months ended September 30, 2022, the final performance factor under the 2020 LTIP was approved and 31,830 performance-based shares were granted under the 2020 LTIP for accounting purposes. As such, NW Natural and other subsidiaries began recognizing compensation expense. In February 2021 and 2022, LTIP shares were awarded to participants; however, the agreements allow for one of the performance factors to remain variable until the first quarter of the third year of the award period. As the performance factor will not be approved until the first quarters of 2023 and 2024, respectively, there is not a mutual understanding of the awards' key terms and conditions between NW Holdings and the participants as of September 30, 2022, and therefore, no expense was recognized for the 2021 and 2022 awards. NW Holdings will calculate the grant date fair value and NW Natural will recognize expense over the remaining service period for each award once the final performance factor has been approved. For the 2021 and 2022 LTIP awards, share payouts range from a threshold of 0% to a maximum of 200% based on achievement of pre-established goals. The performance criteria for the 2021 and 2022 performance shares consists of a three-year Return on Invested Capital (ROIC) threshold that must be satisfied and a cumulative EPS factor, which can be modified by a total shareholder return factor (TSR modifier) relative to the performance of peer group companies over the performance period of three years for each respective award. If the targets were achieved for the 2021 and 2022 awards, NW Holdings would grant for accounting purposes 55,250 and 55,870 shares in the first quarters of 2023 and 2024, respectively. As of September 30, 2022, there wa s $0.1 million of unrecognized compensation cost associated with the 2020 LTIP grants, which is expected to be recognized through 2022. Restricted Stock Units During the nine months ended September 30, 2022, 46,812 RSUs were granted under the LTIP with a weighted-average grant date fair value of $46.60 per share. Generally, the RSUs awarded are forfeitable and include a performance-based threshold as well as a vesting period of four years from the grant date. The majority of our RSU grants obligate NW Holdings, upon vesting, to issue the RSU holder one share of common stock. The grant may also include a cash payment equal to the total amount of dividends paid per share between the grant date and vesting date of that portion of the RSU depending on the structure of the award agreement. The fair value of an RSU is equal to the closing market price of NW Holdings' common stock on the grant date. As of September 30, 2022, there was $3.8 million of unrecognized compensation cost from grants of RSUs, which is expected to be recognized over a period extending through 2026.

Debt

Debt	9 Months Ended
	Sep. 30, 2022
Debt Disclosure [Abstract]
Debt	DEBT Short-Term Debt At September 30, 2022, NW Holdings and NW Natural had short-term debt outstanding of $141.0 million and $53.0 million, respectively. NW Holdings' short-term debt consisted of $88.0 million of balances outstanding under the credit agreement at NW Holdings and $53.0 million of commercial paper outstanding at NW Natural. The weighted average interest rate on the credit agreement at September 30, 2022 was 4.7% at NW Holdings. The weighted average interest rate of commercial paper at September 30, 2022 was 3.3% at NW Natural. At September 30, 2022, NW Natural's commercial paper had a maximum remaining maturity of 18 days and an average remaining maturity of 9 days. Long-Term Debt At September 30, 2022, NW Holdings and NW Natural had long-term debt outstanding of $1,337.6 million and $1,126.5 million, respectively, which included $8.3 million and $8.2 million of unamortized debt issuance costs at NW Holdings and NW Natural, respectively. NW Natural's long-term debt consists of first mortgage bonds (FMBs) with maturity dates ranging from 2023 through 2052, interest rates ranging from 2.8% to 7.9%, and a weighted average interest rate of 4.5%. $50.0 million of long-term debt is scheduled to mature over the next twelve months as of September 30, 2022 at NW Natural. In September 2022, NW Holdings entered into an 18-month credit agreement for $100.0 million and borrowed the full amount. The loan carried an interest rate of 4.1% at September 30, 2022, which is based on the Secured Overnight Financing Rate. The loan is due and payable on March 15, 2024. The credit agreement prohibits NW Holdings from permitting consolidated indebtedness to be greater than 70% of total capitalization, each as defined therein and calculated as of the end of each fiscal quarter. Failure to comply with this financial covenant would entitle the lenders to accelerate the maturity of the amounts outstanding under the credit agreement. NW Holdings was in compliance with this financial covenant as of September 30, 2022. In September 2022, NWN Water entered into an 18-month credit agreement for $50.0 million and borrowed the full amount. The loan carried an interest rate of 4.1% at September 30, 2022, which is based on the Secured Overnight Financing Rate. The loan is due and payable on March 15, 2024. The credit agreement prohibits NWN Water and NW Holdings from permitting consolidated indebtedness to be greater than 70% of total capitalization, each as defined therein and calculated as of the end of each fiscal quarter. Failure to comply with this financial covenant would entitle the lenders to accelerate the maturity of the amounts outstanding under the credit agreement. NWN Water and NW Holdings were in compliance with this financial covenant as of September 30, 2022. In July 2022, NW Natural entered into a Bond Purchase Agreement between NW Natural and the institutional investors named as purchasers therein (the Bond Purchase Agreement). The Bond Purchase Agreement provides for the issuance of $140.0 million aggregate principal amount of NW Natural's First Mortgage Bonds due in 2052 (the Bonds). The Bonds were issued on September 30, 2022. The Bonds bear interest at the rate of 4.8% per annum, payable semi-annually on March 30 and September 30 of each year, commencing March 30, 2023, and will mature on September 30, 2052. The Bonds are subject to redemption prior to maturity at the option of NW Natural, in whole or in part, (i) at any time prior to March 30, 2052, at a redemption price equal to 100% of the principal amount thereof plus a “make-whole” premium and accrued and unpaid interest thereon to the date of redemption, and (ii) at any time on and after March 30, 2052, at 100% of the principal amount thereof plus accrued and unpaid interest thereon to the date of redemption. In June 2021, NWN Water entered into a five Fair Value of Long-Term Debt NW Holdings' and NW Natural's outstanding debt does not trade in active markets. The fair value of debt is estimated using the value of outstanding debt at natural gas distribution companies with similar credit ratings, terms, and remaining maturities to NW Holdings' and NW Natural's debt that actively trade in public markets. Substantially all outstanding debt at NW Holdings is comprised of NW Natural debt. These valuations are based on Level 2 inputs as defined in the fair value hierarchy. See Note 2 in the 2021 Form 10-K for a description of the fair value hierarchy. The following table provides an estimate of the fair value of long-term debt, including current maturities of long-term debt, using market prices in effect on the valuation date: September 30, December 31, In thousands 2022 2021 2021 NW Natural: Gross long-term debt $ 1,134,700 $ 864,700 $ 994,700 Unamortized debt issuance costs (8,229) (6,940) (8,205) Carrying amount $ 1,126,471 $ 857,760 $ 986,495 Estimated fair value (1) $ 927,372 $ 978,613 $ 1,110,741 NW Holdings: Gross long-term debt $ 1,345,968 $ 923,355 $ 1,053,241 Unamortized debt issuance costs (8,348) (7,051) (8,309) Carrying amount $ 1,337,620 $ 916,304 $ 1,044,932 Estimated fair value (1) $ 1,133,087 $ 1,042,705 $ 1,174,500 (1) Estimated fair value does not include unamortized debt issuance costs.

Pension and Other Postretiremen

Pension and Other Postretirement Benefit Costs	9 Months Ended
	Sep. 30, 2022
Pension and Other Postretirement Benefits Cost (Reversal of Cost) [Abstract]
Pension and Other Postretirement Benefit Costs	PENSION AND OTHER POSTRETIREMENT BENEFIT COSTS NW Natural maintains a qualified non-contributory defined benefit pension plan (Pension Plan), non-qualified supplemental pension plans for eligible executive officers and other key employees, and other postretirement employee benefit plans. NW Natural also has a qualified defined contribution plan (Retirement K Savings Plan) for all eligible employees. The Pension Plan and Retirement K Savings Plan have plan assets, which are held in qualified trusts to fund retirement benefits. The service cost component of net periodic benefit cost for NW Natural pension and other postretirement benefit plans is recognized in operations and maintenance expense in the consolidated statements of comprehensive income. The other non-service cost components are recognized in other income (expense), net in the consolidated statements of comprehensive income. The following table provides the components of net periodic benefit cost (credit) for the pension and other postretirement benefit plans: Three Months Ended September 30, Nine Months Ended September 30, Pension Benefits Other Postretirement Pension Benefits Other In thousands 2022 2021 2022 2021 2022 2021 2022 2021 Service cost $ 1,022 $ 1,717 $ 34 $ 69 $ 4,450 $ 5,145 $ 145 $ 180 Interest cost 4,260 3,316 213 180 10,945 10,001 543 510 Expected return on plan assets (7,076) (5,802) — — (19,274) (18,000) — — Amortization of prior service credit — — (15) (119) — — (249) (353) Amortization of net actuarial loss (1,542) 5,515 57 226 9,459 16,516 319 488 Net periodic benefit cost (credit) (3,336) 4,746 289 356 5,580 13,662 758 825 Amount allocated to construction (496) (759) (14) (27) (1,965) (2,228) (57) (70) Net periodic benefit cost (credit) charged to expense (3,832) 3,987 275 329 3,615 11,434 701 755 Amortization of regulatory balancing account 675 675 — — 4,757 4,757 — — Net amount charged to expense $ (3,157) $ 4,662 $ 275 $ 329 $ 8,372 $ 16,191 $ 701 $ 755 Net periodic benefit costs are reduced by amounts capitalized to NGD plant. In addition, net periodic benefit costs were recorded to a regulatory balancing account as approved by the OPUC and amortized accordingly. The following table presents amounts recognized in accumulated other comprehensive loss (AOCL) and the changes in AOCL related to non-qualified employee benefit plans: Three Months Ended September 30, Nine Months Ended September 30, In thousands 2022 2021 2022 2021 Beginning balance $ (11,010) $ (12,460) $ (11,404) $ (12,902) Amounts reclassified from AOCL: Amortization of actuarial losses 275 314 811 916 Total reclassifications before tax 275 314 811 916 Tax benefit (73) (80) (215) (240) Total reclassifications for the period 202 234 596 676 Ending balance $ (10,808) $ (12,226) $ (10,808) $ (12,226) Employer Contributions to Company-Sponsored Defined Benefit Pension Plans NW Natural made no cash contributions to its qualified defined benefit pension plans during the nine months ended September 30, 2022 compared to $9.6 million for the same period in 2021. NW Natural does not expect to make any plan contributions during the remainder of 2022 as a result of adopting the American Rescue Plan Act. Defined Contribution Plan NW Natural's Retirement K Savings Plan is a qualified defined contribution plan under Internal Revenue Code Sections 401(a) and 401(k). NW Natural contributions totaled $7.4 million and $6.7 million for the nine months ended September 30, 2022 and 2021, respectively. See Note 10 in the 2021 Form 10-K for more information concerning these retirement and other postretirement benefit plans.

Income Tax

Income Tax	9 Months Ended
	Sep. 30, 2022
Income Tax Disclosure [Abstract]
Income Tax	INCOME TAX An estimate of annual income tax expense is made each interim period using estimates for annual pre-tax income, regulatory flow-through adjustments, tax credits, and other items. The estimated annual effective tax rate is applied to year-to-date, pre-tax income to determine income tax expense for the interim period consistent with the annual estimate. Discrete events are recorded in the interim period in which they occur or become known. The effective income tax rate varied from the federal statutory rate due to the following: Three Months Ended September 30, NW Holdings NW Natural In thousands 2022 2021 2022 2021 Income tax at statutory rate (federal) $ (5,533) $ (5,834) $ (5,305) $ (5,928) State income tax (2,376) (2,599) (2,306) (2,618) Increase (decrease): Differences required to be flowed-through by regulatory commissions 1,232 1,318 1,232 1,318 Other, net (81) (12) (76) 16 Total provision for income taxes $ (6,758) $ (7,127) $ (6,455) $ (7,212) Effective income tax rate 25.7 % 25.7 % 25.6 % 25.5 % Nine Months Ended September 30, NW Holdings NW Natural In thousands 2022 2021 2022 2021 Income tax at statutory rate (federal) $ 10,710 $ 10,764 $ 11,554 $ 11,195 State income tax 4,298 4,660 4,497 4,748 Increase (decrease): Differences required to be flowed-through by regulatory commissions (2,003) (2,266) (2,003) (2,266) Other, net (370) (41) (370) (49) Total provision for income taxes $ 12,635 $ 13,117 $ 13,678 $ 13,628 Effective income tax rate 24.8 % 25.6 % 24.9 % 25.6 % The NW Holdings and NW Natural effective income tax rates for the nine months ended September 30, 2022 compared to the same period in 2021 changed primarily as a result of changes in pre-tax income. See Note 11 in the 2021 Form 10-K for more detail on income taxes and effective tax rates. The IRS Compliance Assurance Process (CAP) examination of the 2020 tax year was completed during the first quarter of 2022. There were no material changes to the return as filed. The 2021 and 2022 tax years are subject to examination under CAP.

Property, Plant and Equipment

Property, Plant and Equipment	9 Months Ended
	Sep. 30, 2022
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment Disclosure [Text Block]	PROPERTY, PLANT, AND EQUIPMENT The following table sets forth the major classifications of property, plant, and equipment and accumulated depreciation: September 30, December 31, In thousands 2022 2021 2021 NW Natural: NGD plant in service $ 3,888,092 $ 3,663,699 $ 3,721,939 NGD construction work in progress 161,658 120,412 135,398 Less: Accumulated depreciation 1,135,965 1,086,510 1,098,715 NGD plant, net 2,913,785 2,697,601 2,758,622 Other plant in service 69,626 66,314 69,332 Other construction work in progress 5,112 7,228 4,971 Less: Accumulated depreciation 21,435 20,392 20,646 Other plant, net 53,303 53,150 53,657 Total property, plant, and equipment, net $ 2,967,088 $ 2,750,751 $ 2,812,279 Other (NW Holdings): Other plant in service $ 66,208 $ 53,175 $ 57,184 Other construction work in progress 16,632 8,268 8,419 Less: Accumulated depreciation 8,750 5,832 6,512 Other plant, net $ 74,090 $ 55,611 $ 59,091 NW Holdings: Total property, plant, and equipment, net $ 3,041,178 $ 2,806,362 $ 2,871,370 NW Natural: Capital expenditures in accrued liabilities $ 43,954 $ 33,968 $ 37,537 NW Holdings: Capital expenditures in accrued liabilities $ 45,374 $ 35,955 $ 38,333 NW Natural Other plant balances include non-utility gas storage assets at the Mist facility and other long-lived assets not related to NGD. NW Holdings Other plant balances include long-lived assets associated with water and wastewater operations and non-regulated activities not held by NW Natural or its subsidiaries.

Investments

Investments	9 Months Ended
	Sep. 30, 2022
Investments [Abstract]
Investments [Text Block]	INVESTMENTS Investments include gas reserves, financial investments in life insurance policies, and equity method investments. The following table summarizes other investments: NW Holdings NW Natural September 30, December 31, September 30, December 31, In thousands 2022 2021 2021 2022 2021 2021 Investments in life insurance policies $ 49,043 $ 47,970 $ 48,178 $ 49,043 $ 47,970 $ 48,178 Investments in gas reserves, non-current 23,770 28,021 26,608 23,770 28,021 26,608 Investment in unconsolidated affiliates 23,756 36 14,492 8,058 — — Total other investments $ 96,569 $ 76,027 $ 89,278 $ 80,871 $ 75,991 $ 74,786 Investment in Life Insurance Policies Other investments include financial investments in life insurance policies, which are accounted for at cash surrender value, net of policy loans. See Note 13 in the 2021 Form 10-K. NW Natural Gas Reserves NW Natural has invested $188 million through the gas reserves program in the Jonah Field located in Wyoming as of September 30, 2022. Gas reserves are stated at cost, net of regulatory amortization, with the associated deferred tax benefits of $5.5 million, $7.8 million, and $6.9 million, which are recorded as liabilities in the September 30, 2022, September 30, 2021, and December 31, 2021 consolidated balance sheets, respectively. NW Natural's investment is included in NW Holdings' and NW Natural's consolidated balance sheets under other current assets and other investments (non-current portion) with the maximum loss exposure limited to the investment balance. The amount of gas reserves included in other current assets was $3.7 million, $6.3 million, and $5.4 million as of September 30, 2022, September 30, 2021, and December 31, 2021, respectively. See Note 13 in the 2021 Form 10-K. Investments in Unconsolidated Affiliates In December 2021, NW Natural Water purchased a 37.3% ownership stake in Avion Water Company, Inc. (Avion Water), an investor-owned water utility for $14.5 million. In July 2022, NW Natural Water increased its ownership stake in Avion Water to 40.3% for an additional $1.0 million. Avion Water operates in Bend, Oregon and the surrounding communities, serving approximately 15,000 customer connections and employing 35 people. The carrying value of the equity method investment is $10.6 million higher than the underlying equity in the net assets of the investee at September 30, 2022 due to equity method goodwill. NW Natural Water's share in the earnings (loss) of Avion Water is included in other income (expense), net. In 2020, NW Natural began a partnership with BioCarbN to invest in up to four separate RNG development projects that will access biogas derived from water treatment at Tyson Foods’ processing plants, subject to approval by all parties. During the construction phase of the projects, NW Natural determined it is the primary beneficiary and fully consolidates each entity. In 2022, commissioning of the first project, Lexington Renewable Energy LLC (Lexington), was completed and NW Natural determined it was no longer the primary beneficiary and deconsolidated the variable interest entity and recorded the investment in Lexington as an equity method investment. NW Natural accounts for its interest in Lexington using the equity method of accounting because NW Natural does not control but has the ability to exercise significant influence over Lexington's operations after commissioning. There was no gain or loss recognized upon deconsolidation. NW Natural determined the fair value of the investment approximated the carrying value which was primarily comprised of cash and property, plant and equipment. As of September 30, 2022, NW Natural had an investment balance in Lexington of $8.1 million. NW Natural's share in the earnings (loss) of Lexington is included in cost of gas.

Business Combinations Business

Business Combinations Business Combinations	9 Months Ended
	Sep. 30, 2022
Business Combinations [Abstract]
Business Combination Disclosure	BUSINESS COMBINATIONS 2022 Business Combinations During the nine months ended September 30, 2022, NWN Water and its subsidiaries completed three acquisitions qualifying as business combinations. The aggregate fair value of the preliminary consideration transferred for these acquisitions was $4.2 million, most of which was preliminarily allocated to property, plant and equipment and goodwill. These transactions align with NW Holdings' water sector strategy as it continues to expand its water and wastewater service territories and included: • Belle Oaks Water and Sewer Co., Inc was acquired by NWN Water of Texas in May 2022 • Northwest Water Services, LLC was acquired by NWN Water of Washington in August 2022 • Aquarius Utilities, LLC was acquired by NWN Water of Washington in August 2022 As each of these acquisitions met the criteria of a business combination, a preliminary allocation of the consideration to the acquired net assets based on their estimated fair value as of the acquisition date was performed. The allocation for each of these business combinations is considered preliminary as of September 30, 2022. In accordance with U.S. GAAP, the fair value determination involves management judgment in determining the significant estimates and assumptions used and was made using existing regulatory conditions for net assets associated with Belle Oaks Water and Sewer Co., Northwest Water Services, LLC, and Aquarius Utilities, LLC. These allocations are considered preliminary as of September 30, 2022, as facts and circumstances that existed as of the acquisition date may be discovered as we continue to integrate the acquired businesses. As a result, subsequent adjustments to the preliminary valuation of tangible assets, contract assets and liabilities, tax positions, and goodwill may be required. Subsequent adjustments are not expected to be significant, and any such adjustments are expected to be completed within the one-year measurement period for all acquisitions described above. 2021 Business Combinations During 2021, NWN Water and its subsidiaries completed four acquisitions qualifying as business combinations. The aggregate fair value of the preliminary consideration transferred for these acquisitions were not material and are not significant to NW Holdings' results of operations. Goodwill NW Holdings allocates goodwill to reporting units based on the expected benefit from the business combination. We perform an annual impairment assessment of goodwill at the reporting unit level, or more frequently if events and circumstances indicate that goodwill might be impaired. An impairment loss is recognized if the carrying value of a reporting unit’s goodwill exceeds its fair value. As a result of all acquisitions completed, total goodwill was $74.7 million, $69.8 million, and $70.6 million as of September 30, 2022, September 30, 2021, and December 31, 2021, respectively. All of our goodwill is related to water and wastewater acquisitions and is included in the other category for segment reporting purposes. The annual impairment assessment of goodwill occurs in the fourth quarter of each year. There have been no impairments recognized to date.

Derivative Instruments

Derivative Instruments	9 Months Ended
	Sep. 30, 2022
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	DERIVATIVE INSTRUMENTS NW Natural enters into financial derivative contracts to hedge a portion of the NGD segment's natural gas sales requirements. These contracts include swaps, options, and combinations of option contracts. These derivative financial instruments are primarily used to manage commodity price variability. A small portion of NW Natural's derivative hedging strategy involves foreign currency forward contracts. NW Natural enters into these financial derivatives, up to prescribed limits, primarily to hedge price variability related to term physical gas supply contracts as well as to hedge spot purchases of natural gas. The foreign currency forward contracts are used to hedge the fluctuation in foreign currency exchange rates for pipeline demand charges paid in Canadian dollars. In the normal course of business, NW Natural also enters into indexed-price physical forward natural gas commodity purchase contracts and options to meet the requirements of NGD customers. These contracts qualify for regulatory deferral accounting treatment. NW Natural also enters into exchange contracts related to the third-party asset management of its gas portfolio, some of which are derivatives that do not qualify for hedge accounting or only partial regulatory deferral, but are subject to NW Natural's regulatory sharing agreement. These derivatives are recognized in operating revenues, net of amounts shared with NGD customers. Notional Amounts The following table presents the absolute notional amounts related to open positions on NW Natural derivative instruments: September 30, December 31, In thousands 2022 2021 2021 Natural gas (in therms): Financial 1,006,665 749,595 618,815 Physical 672,350 613,524 431,628 Foreign exchange $ 9,905 $ 6,299 $ 6,268 Purchased Gas Adjustment (PGA) Under the PGA mechanism in Oregon, derivatives entered into by NW Natural for the procurement or hedging of natural gas for future gas years generally receive regulatory deferral accounting treatment. In general, commodity hedging for the current gas year is completed prior to the start of the gas year, and hedge prices are reflected in the weighted-average cost of gas in the PGA filing. Hedge contracts entered into prior to the PGA filing were included in the PGA for the 2022-23 gas year. Hedge contracts entered into after the start of the PGA period are subject to the PGA incentive sharing mechanism in Oregon. Under the PGA mechanism in Washington, NW Natural incorporates risk-responsive hedging strategies and receives regulatory deferral accounting treatment for its Washington gas supplies. As of September 30, 2022, NW Natural's forecasted sales volume was hedged at approximately 80% in total for the 2022-23 gas year. The total hedged for Oregon was also approximately 80%, including 63% in financial hedges and 17% in physical gas supplies. The total hedged for Washington was approximately 79%, including 66% in financial hedges and 13% in physical gas supplies. Unrealized and Realized Gain/Loss The following table reflects the income statement presentation for the unrealized gains and losses from NW Natural's derivative instruments, which also represents all derivative instruments at NW Holdings: Three Months Ended September 30, 2022 2021 In thousands Natural gas commodity Foreign exchange Natural gas commodity Foreign exchange Benefit (expense) to cost of gas $ (11,626) $ (455) $ 69,239 $ (106) Operating revenues (expense) — — — — Amounts deferred to regulatory accounts on balance sheet 11,626 455 (69,239) 106 Total gain (loss) in pre-tax earnings $ — $ — $ — $ — Nine Months Ended September 30, 2022 2021 In thousands Natural gas commodity Foreign exchange Natural gas commodity Foreign exchange Benefit (expense) to cost of gas $ 32,827 $ (528) $ 106,044 $ (74) Operating revenues (expense) — — (26) — Amounts deferred to regulatory accounts on balance sheet (32,827) 528 (106,022) 74 Total gain (loss) in pre-tax earnings $ — $ — $ (4) $ — Unrealized Gain/Loss Outstanding derivative instruments related to regulated NGD operations are deferred in accordance with regulatory accounting standards. The cost of foreign currency forward and natural gas derivative contracts are recognized immediately in the cost of gas; however, costs above or below the amount embedded in the current year PGA are subject to a regulatory deferral tariff and therefore, are recorded as a regulatory asset or liability. Realized Gain/Loss NW Natural realized ne t gains of $16.9 million and $74.0 million for the three and nine months ended September 30, 2022, respectively, from the settlement of natural gas financial derivative contracts, whereas, net gains of $6.1 million and $15.4 million were realized for the three and nine months ended September 30, 2021, respectively. Realized gains and losses offset the higher or lower cost of gas purchased, resulting in no incremental amounts to collect or refund to customers. Credit Risk Management of Financial Derivatives Instruments No collateral was posted with or by NW Natural counterparties as of September 30, 2022 or 2021. NW Natural attempts to minimize the potential exposure to collateral calls by diversifying counterparties and using credit limits to manage liquidity risk. Counterparties generally allow a certain credit limit threshold before requiring NW Natural to post collateral against unrealized loss positions. Given NW Natural's credit ratings, counterparty credit limits and portfolio diversification, it was not subject to collateral calls in 2022 or 2021. The collateral call exposure is set forth under credit support agreements, which generally contain credit limits. NW Natural could also be subject to collateral call exposure where it has agreed to provide adequate assurance, which is not specific as to the amount of credit limit allowed, but could potentially require additional collateral posting by NW Natural in the event of a material adverse change. NW Natural's financial derivative instruments are subject to master netting arrangements; however, they are presented on a gross basis in the consolidated balance sheets. NW Natural and its counterparties have the ability to set-off obligations to each other under specified circumstances. Such circumstances may include a defaulting party, a credit change due to a merger affecting either party, or any other termination event. NW Natural's current commodity financial swap and option contracts outstanding reflect unrealized gains of $35.1 million and $132.2 million at September 30, 2022 and 2021. If netted by counterparty, NW Natural's physical and financial derivative position would result in an asset of $40.8 million and a liability of $8.5 million as of September 30, 2022, an asset of $124.5 million and a liability of $4.9 million as of September 30, 2021, and an asset of $51.8 million and a liability of $3.8 million as of December 31, 2021. NW Natural is exposed to derivative credit and liquidity risk primarily through securing fixed price natural gas commodity swaps with financial counterparties. NW Natural utilizes master netting arrangements through International Swaps and Derivatives Association contracts to minimize this risk along with collateral support agreements with counterparties based on their credit ratings. Additionally, NW Natural uses counterparty, industry sector and country diversification to minimize credit risk. In certain cases, NW Natural may require counterparties to post collateral, guarantees, or letters of credit to maintain its minimum credit requirement standards. See Note 15 in the 2021 Form 10-K for additional information. Fair Value In accordance with fair value accounting, NW Natural includes non-performance risk in calculating fair value adjustments. This includes a credit risk adjustment based on the credit spreads of NW Natural counterparties when in an unrealized gain position, or on NW Natural's own credit spread when it is in an unrealized loss position. The inputs in our valuation models include natural gas futures, volatility, credit default swap spreads and interest rates. Additionally, the assessment of non-performance risk is generally derived from the credit default swap market and from bond market credit spreads. The impact of the credit risk adjustments for all financial derivatives outstanding was immaterial to the fair value calculation at September 30, 2022. The net fair value was an asset of $32.3 million,

Environmental Matters

Environmental Matters	9 Months Ended
	Sep. 30, 2022
Environmental Remediation Obligations [Abstract]
Environmental Matters	ENVIRONMENTAL MATTERS NW Natural owns, or previously owned, properties that may require environmental remediation or action. The range of loss for environmental liabilities is estimated based on current remediation technology, enacted laws and regulations, industry experience gained at similar sites, and an assessment of the probable level of involvement and financial condition of other potentially responsible parties (PRPs). When amounts are prudently expended related to site remediation of those sites described herein, NW Natural has recovery mechanisms in place to collect 96.7% of remediation costs allocable to Oregon customers and 3.3% of costs allocable to Washington customers. These sites are subject to the remediation process prescribed by the Environmental Protection Agency (EPA) and the Oregon Department of Environmental Quality (ODEQ). The process begins with a remedial investigation (RI) to determine the nature and extent of contamination and then a risk assessment (RA) to establish whether the contamination at the site poses unacceptable risks to humans and the environment. Next, a feasibility study (FS) or an engineering evaluation/cost analysis (EE/CA) evaluates various remedial alternatives. It is at this point in the process when NW Natural is able to estimate a range of remediation costs and record a reasonable potential remediation liability, or make an adjustment to the existing liability. From this study, the regulatory agency selects a remedy and issues a Record of Decision (ROD). After a ROD is issued, NW Natural would seek to negotiate a consent decree or consent judgment for designing and implementing the remedy. NW Natural would have the ability to further refine estimates of remediation liabilities at that time. Remediation may include treatment of contaminated media such as sediment, soil and groundwater, removal and disposal of media, institutional controls such as legal restrictions on future property use, or natural recovery. Following construction of the remedy, the EPA and ODEQ also have requirements for ongoing maintenance, monitoring and other post-remediation care that may continue for many years. Where appropriate and reasonably known, NW Natural will provide for these costs in the remediation liabilities described below. Due to the numerous uncertainties surrounding the course of environmental remediation and the preliminary nature of several site investigations, in some cases, NW Natural may not be able to reasonably estimate the high end of the range of possible loss. In those cases, the nature of the possible loss has been disclosed, as has the fact that the high end of the range cannot be reasonably estimated where a range of potential loss is available. Unless there is an estimate within the range of possible losses that is more likely than other cost estimates within that range, NW Natural records the liability at the low end of this range. It is likely changes in these estimates and ranges will occur throughout the remediation process for each of these sites due to the continued evaluation and clarification concerning responsibility, the complexity of environmental laws and regulations and the determination by regulators of remediation alternatives. In addition to remediation costs, NW Natural could also be subject to Natural Resource Damages (NRD) claims. NW Natural will assess the likelihood and probability of each claim and recognize a liability if deemed appropriate. Refer to "Other Portland Harbor" below. Environmental Sites The following table summarizes information regarding liabilities related to environmental sites, which are recorded in other current liabilities and other noncurrent liabilities in NW Natural's balance sheet: Current Liabilities Non-Current Liabilities September 30, December 31, September 30, December 31, In thousands 2022 2021 2021 2022 2021 2021 Portland Harbor site: Gasco/Siltronic Sediments $ 5,556 $ 6,925 $ 7,582 $ 40,740 $ 40,929 $ 42,076 Other Portland Harbor 2,430 2,392 2,592 8,135 6,222 9,570 Gasco/Siltronic Upland site 8,367 9,720 15,711 33,354 37,408 36,215 Front Street site 201 1,002 1,100 868 893 811 Oregon Steel Mills — — — 179 179 179 Total $ 16,554 $ 20,039 $ 26,985 $ 83,276 $ 85,631 $ 88,851 Portland Harbor Site The Portland Harbor is an EPA listed Superfund site that is approximately 10 miles long on the Willamette River and is adjacent to NW Natural's Gasco uplands site. NW Natural is one of over one hundred PRPs, each jointly and severally liable, at the Superfund site. In January 2017, the EPA issued its Record of Decision, which selects the remedy for the clean-up of the Portland Harbor site (Portland Harbor ROD). The Portland Harbor ROD estimates the present value total cost at approximately $1.05 billion with an accuracy between -30% and +50% of actual costs. NW Natural's potential liability is a portion of the costs of the remedy for the entire Portland Harbor Superfund site. The cost of that remedy is expected to be allocated among more than one hundred PRPs. NW Natural is participating in a non-binding allocation process with other PRPs in an effort to resolve its potential liability. The Portland Harbor ROD does not provide any additional clarification around allocation of costs among PRPs; accordingly, NW Natural has not modified any of the recorded liabilities at this time as a result of the issuance of the Portland Harbor ROD. NW Natural manages its liability related to the Superfund site as two distinct remediation projects: the Gasco Sediments Site and Other Portland Harbor projects. GASCO SEDIMENTS. In 2009, NW Natural and Siltronic Corporation entered into a separate Administrative Order on Consent with the EPA to evaluate and design specific remedies for sediments adjacent to the Gasco uplands and Siltronic uplands sites. NW Natural submitted a draft EE/CA to the EPA in May 2012 to provide the estimated cost of potential remedial alternatives for this site. In March 2020, NW Natural and the EPA amended the Administrative Order on Consent to include additional remedial design activities downstream of the Gasco sediments site and in the navigation channel. Siltronic Corporation is not a party to the amended order. In the second quarter of 2021, NW Natural began preliminary design discussions with the EPA for the Gasco sediments site. These preliminary design discussions did not include a cost estimate for cleanup. No design alternatives are more likely than the EE/CA alternatives at this time, and NW Natural expects further design discussion and iteration with the EPA. The estimated costs for the various sediment remedy alternatives in the draft EE/CA, for the additional studies and design work needed before the cleanup can occur, and for regulatory oversight throughout the cleanup range from $46.3 million to $350 million. NW Natural has recorded a liability of $46.3 million for the Gasco sediment clean-up, which reflects the low end of the range. At this time, we believe sediments at the Gasco sediments site represent the largest portion of NW Natural's liability related to the Portland Harbor site discussed above. OTHER PORTLAND HARBOR. While we believe liabilities associated with the Gasco sediments site represent NW Natural's largest exposure, there are other potential exposures associated with the Portland Harbor ROD, including NRD costs and harborwide remedial design and cleanup costs (including downstream petroleum contamination), for which allocations among the PRPs have not yet been determined. NW Natural and other parties have signed a cooperative agreement with the Portland Harbor Natural Resource Trustee council to participate in a phased NRD assessment to estimate liabilities to support an early restoration-based settlement of NRD claims. One member of this Trustee council, the Yakama Nation, withdrew from the council in 2009, and in 2017, filed suit against NW Natural and 29 other parties seeking remedial costs and NRD assessment costs associated with the Portland Harbor site, set forth in the complaint. The complaint seeks recovery of alleged costs totaling $0.3 million in connection with the selection of a remedial action for the Portland Harbor site as well as declaratory judgment for unspecified future remedial action costs and for costs to assess the injury, loss or destruction of natural resources resulting from the release of hazardous substances at and from the Portland Harbor site. The Yakama Nation has filed two amended complaints addressing certain pleading defects and dismissing the State of Oregon. On the motion of NW Natural and certain other defendants, the federal court has stayed the case pending the outcome of the non-binding allocation proceeding discussed above. NW Natural has recorded a liability for NRD claims which is at the low end of the range of the potential liability; the high end of the range cannot be reasonably estimated at this time. The NRD liability is not included in the aforementioned range of costs provided in the Portland Harbor ROD. Gasco Uplands Site A predecessor of NW Natural, Portland Gas and Coke Company, owned a former gas manufacturing plant that was closed in 1958 (Gasco site) and is adjacent to the Portland Harbor site described above. The Gasco site has been under investigation by NW Natural for environmental contamination under the ODEQ Voluntary Cleanup Program (VCP). It is not included in the range of remedial costs for the Portland Harbor site noted above. The Gasco site is managed in two parts, the uplands portion and the groundwater source control action. NW Natural submitted a revised Remedial Investigation Report for the uplands to ODEQ in May 2007. In March 2015, ODEQ approved the Risk Assessment (RA) for this site, enabling commencement of work on the FS in 2016. NW Natural has recognized a liability for the remediation of the uplands portion of the site which is at the low end of the range of potential liability; the high end of the range cannot be reasonably estimated at this time. In October 2016, ODEQ and NW Natural agreed to amend their VCP agreement for the Gasco uplands to incorporate a portion of the Siltronic property formerly owned by Portland Gas & Coke between 1939 and 1960 into the Gasco RA and FS. Previously, NW Natural was conducting an investigation of manufactured gas plant constituents on the entire Siltronic uplands for ODEQ. Siltronic will be working with ODEQ directly on environmental impacts to the remainder of its property. In September 2013, NW Natural completed construction of a groundwater source control system, including a water treatment station, at the Gasco site. NW Natural has estimated the cost associated with the ongoing operation of the system and has recognized a liability which is at the low end of the range of potential cost. NW Natural cannot estimate the high end of the range at this time due to the uncertainty associated with the duration of running the water treatment station, which is highly dependent on the remedy determined for both the upland portion as well as the final remedy for the Gasco sediments site. Other Sites In addition to those sites above, NW Natural has environmental exposures at three other sites: Central Service Center, Front Street and Oregon Steel Mills. NW Natural may have exposure at other sites that have not been identified at this time. Due to the uncertainty of the design of remediation, regulation, timing of the remediation and in the case of the Oregon Steel Mills site, pending litigation, liabilities for each of these sites have been recognized at their respective low end of the range of potential liability; the high end of the range could not be reasonably estimated at this time. FRONT STREET SITE. The Front Street site was the former location of a gas manufacturing plant NW Natural operated (the former Portland Gas Manufacturing site, or PGM). At ODEQ’s request, NW Natural conducted a sediment and source control investigation and provided findings to ODEQ. In December 2015, an FS on the former Portland Gas Manufacturing site was completed. In July 2017, ODEQ issued the PGM ROD. The ROD specifies the selected remedy, which requires a combination of dredging, capping, treatment, and natural recovery. In addition, the selected remedy also requires institutional controls and long-term inspection and maintenance. Construction of the remedy began in July 2020 and was completed in October 2020. The first year of post-construction monitoring was completed in 2021 and demonstrated that the cap was intact and performing as designed. NW Natural has recognized an additional liability of $1.1 million costs associated with the discovery during construction of World War II-era munitions, design costs, regulatory and permitting issues, and post-construction work. OREGON STEEL MILLS SITE. Refer to " Legal Proceedings" below. Environmental Cost Deferral and Recovery NW Natural has authorizations in Oregon and Washington to defer costs related to remediation of properties that are owned or were previously owned by NW Natural. In Oregon, a Site Remediation and Recovery Mechanism (SRRM) is currently in place to recover prudently incurred costs allocable to Oregon customers, subject to an earnings test. On October 21, 2019, the WUTC authorized an Environmental Cost Recovery Mechanism (ECRM) for recovery of prudently incurred costs allocable to Washington customers beginning November 1, 2019 . See Note 17 in the 2021 Form 10-K for a description of SRRM and ECRM collection processes. The following table presents information regarding the total regulatory asset deferred: September 30, December 31, In thousands 2022 2021 2021 Deferred costs and interest (1) $ 47,011 $ 45,019 $ 45,122 Accrued site liabilities (2) 99,795 105,607 115,773 Insurance proceeds and interest (54,678) (59,589) (59,564) Total regulatory asset deferral (1) $ 92,128 $ 91,037 $ 101,331 Current regulatory assets (3) 9,461 7,068 6,694 Long-term regulatory assets (3) 82,667 83,969 94,636 (1) Includes pre-review and post-review deferred costs, amounts currently in amortization, and interest, net of amounts collected from customers. (2) Exclude s 3.3% of the Front Street site liability as the OPUC only allows recovery of 96.7% of costs for those sites allocable to Oregon, including those that historically served only Oregon customers. Amounts excluded from regulatory assets were $34 thousand at September 30, 2022, $62 thousand at September 30, 2021, and $62 thousand at December 31, 2021. (3) Environmental costs relate to specific sites approved for regulatory deferral by the OPUC and WUTC. In Oregon, NW Natural earns a carrying charge on cash amounts paid, whereas amounts accrued but not yet paid do not earn a carrying charge until expended. It also accrues a carrying charge on insurance proceeds for amounts owed to customers. In Washington, neither the cash paid for insurance proceeds received accrue a carrying charge. Current environmental costs represent remediation costs management expects to collect from customers in the next 12 months. Amounts included in this estimate are still subject to a prudence and earnings test review by the OPUC and do not include the $5.0 million tariff rider. The amounts allocable to Oregon are recoverable through NGD rates, subject to an earnings test. Environmental Earnings Test To the extent NW Natural earns at or below its authorized Return on Equity (ROE) as defined by the SRRM, remediation expenses and interest in excess of the $5.0 million tariff rider and $5.0 million insurance proceeds are recoverable through the SRRM. To the extent NW Natural earns more than its authorized ROE in a year, it is required to cover environmental expenses and interest on expenses greater than the $10.0 million with those earnings that exceed its authorized ROE. Legal Proceedings NW Holdings is not currently party to any direct claims or litigation, though in the future it may be subject to claims and litigation arising in the ordinary course of business. NW Natural is subject to claims and litigation arising in the ordinary course of business including the matters discussed above. Although the final outcome of any of these legal proceedings cannot be predicted with certainty, including the matter relating to the Oregon Steel Mills site referenced below, NW Natural and NW Holdings do not expect that the ultimate disposition of any of these matters will have a material effect on their financial condition, results of operations or cash flows. See also Part II, Item 1, “Legal Proceedings". Oregon Steel Mills Site See Note 17 in the 2021 Form 10-K. For additional information regarding other commitments and contingencies, see Note 16 in the 2021 Form 10-K.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2022
Subsequent Events [Abstract]
Subsequent Events [Text Block]	SUBSEQUENT EVENT In October 2022, NW Natural Water completed the acquisition of the water and wastewater utilities of Far West Water & Sewer, Inc. for approximately $88 million in cash consideration, subject to closing adjustments. Located in Yuma, Arizona, these utilities serve approximately 25,000 connections in the Foothills area and employ approximately 40 people. Going forward, the utilities will be doing business as Foothills Utilities. The preliminary allocation of consideration to the acquired assets and assumed liabilities based on their fair value is not yet complete as valuation procedures are pending. Acquisition costs were insignificant and were expensed as incurred.

Significant Accounting Polici_2

Significant Accounting Policies	9 Months Ended
	Sep. 30, 2022
Accounting Policies [Abstract]
Industry Regulation	Industry Regulation In applying regulatory accounting principles, NW Holdings and NW Natural capitalize or defer certain costs and revenues as regulatory assets and liabilities pursuant to orders of the Oregon Public Utilities Commission (OPUC), Washington Utilities and Transportation Commission (WUTC), Idaho Public Utilities Commission (IPUC) or Public Utility Commission of Texas (PUCT), as applicable, which provide for the recovery of revenues or expenses from, or refunds to, utility customers in future periods, including a return or a carrying charge in certain cases.
New Accounting Standards	New Accounting Standards NW Natural and NW Holdings consider the applicability and impact of all accounting standards updates (ASUs) issued by the Financial Accounting Standards Board (FASB). ASUs not listed below were assessed and determined to be either not applicable or are expected to have minimal impact on consolidated financial position or results of operations. Recently Adopted Accounting Pronouncements

Significant Accounting Polici_3

Significant Accounting Policies	9 Months Ended
	Sep. 30, 2022
Accounting Policies [Abstract]
Schedule of Regulatory Assets	Amounts deferred as regulatory assets and liabilities for NW Holdings and NW Natural were as follows: Regulatory Assets September 30, December 31, In thousands 2022 2021 2021 NW Natural: Current: Unrealized loss on derivatives (1) $ 19,594 $ 9,818 $ 10,402 Gas costs 52,115 39,622 35,641 Environmental costs (2) 9,461 7,068 6,694 Decoupling (3) 114 1,628 969 Pension balancing (4) 7,131 7,131 7,131 Income taxes 2,399 2,939 2,568 Other (5) 14,016 12,432 8,986 Total current $ 104,830 $ 80,638 $ 72,391 Non-current: Unrealized loss on derivatives (1) $ 18,824 $ 268 $ 412 Pension balancing (4) 34,928 40,176 38,302 Income taxes 11,168 13,912 12,609 Pension and other postretirement benefit liabilities 107,722 155,077 116,440 Environmental costs (2) 82,667 83,969 94,636 Gas costs 3,369 2,858 15,477 Decoupling (3) — 118 — Other (5) 42,918 28,653 36,663 Total non-current $ 301,596 $ 325,031 $ 314,539 Other (NW Holdings) 64 40 40 Total non-current - NW Holdings $ 301,660 $ 325,071 $ 314,579
Schedule of Regulatory Liabilities	Regulatory Liabilities September 30, December 31, In thousands 2022 2021 2021 NW Natural: Current: Gas costs $ 944 $ 847 $ 70 Unrealized gain on derivatives (1) 62,882 105,175 48,130 Decoupling (3) 13,272 4,484 4,475 Income taxes 7,318 8,217 8,192 Asset optimization revenue sharing 23,461 43,883 45,124 Other (5) 3,649 1,562 6,290 Total current - NW Natural $ 111,526 $ 164,168 $ 112,281 Other (NW Holdings) 25 — — Total current - NW Holdings $ 111,551 $ 164,168 $ 112,281 Non-current: Gas costs $ 50 $ — $ 250 Unrealized gain on derivatives (1) 8,008 24,555 10,730 Decoupling (3) 884 214 3,412 Income taxes (6) 179,319 186,429 181,404 Accrued asset removal costs (7) 460,666 440,410 445,952 Asset optimization revenue sharing — — 1,810 Other (5) 13,638 12,913 13,792 Total non-current - NW Natural $ 662,565 $ 664,521 $ 657,350 Other (NW Holdings) 982 869 982 Total non-current - NW Holdings $ 663,547 $ 665,390 $ 658,332 (1) Unrealized gains or losses on derivatives are non-cash items and therefore do not earn a rate of return or a carrying charge. These amounts are recoverable through NGD rates as part of the annual Purchased Gas Adjustment (PGA) mechanism when realized at settlement. (2) Refer to the Environmental Cost Deferral and Recovery table in Note 16 for a description of environmental costs. (3) This deferral represents the margin adjustment resulting from differences between actual and expected volumes. (4) Balance represents deferred net periodic benefit costs as approved by the OPUC. (5) Balances consist of deferrals and amortizations under approved regulatory mechanisms and typically earn a rate of return or carrying charge. (6) Balance represents excess deferred income tax benefits subject to regulatory flow-through.
Schedule of Cash Flow, Supplemental Disclosures	The following table provides a reconciliation of the cash, cash equivalents and restricted cash balances at NW Holdings as of September 30, 2022 and 2021 and December 31, 2021: September 30, December 31, In thousands 2022 2021 2021 Cash and cash equivalents $ 108,556 $ 19,502 $ 18,559 Restricted cash included in other current assets 11,714 8,170 8,561 Cash, cash equivalents and restricted cash $ 120,270 $ 27,672 $ 27,120 The following table provides a reconciliation of the cash, cash equivalents and restricted cash balances at NW Natural as of September 30, 2022 and 2021 and December 31, 2021: September 30, December 31, In thousands 2022 2021 2021 Cash and cash equivalents $ 11,386 $ 9,697 $ 12,271 Restricted cash included in other current assets 11,714 8,170 8,561 Cash, cash equivalents and restricted cash $ 23,100 $ 17,867 $ 20,832
Accounts Receivable, Allowance for Credit Loss [Table Text Block]	The following table presents the activity related to the NW Holdings provision for uncollectible accounts by pool, substantially all of which is related to NW Natural's accounts receivable: As of As of December 31, 2021 Nine Months Ended September 30, 2022 September 30, 2022 In thousands Beginning Balance Provision recorded, net of adjustments Write-offs recognized, net of recoveries Ending Balance Allowance for uncollectible accounts: Residential $ 1,460 $ 896 $ (871) $ 1,485 Commercial 178 375 (272) 281 Industrial 67 173 (62) 178 Accrued unbilled and other 313 84 (170) 227 Total $ 2,018 $ 1,528 $ (1,375) $ 2,171

Earnings Per Share_2

Earnings Per Share	9 Months Ended
	Sep. 30, 2022
Earnings Per Share [Abstract]
EPS Calculation	NW Holdings' diluted earnings or loss per share are calculated as follows: Three Months Ended September 30, Nine Months Ended September 30, In thousands, except per share data 2022 2021 2022 2021 Net income (loss) (19,587) (20,655) 38,367 38,138 Average common shares outstanding - basic 34,939 30,696 33,491 30,659 Additional shares for stock-based compensation plans (See Note 8) — — 48 49 Average common shares outstanding - diluted 34,939 30,696 33,539 30,708 Earnings (loss) per share of common stock: Basic $ (0.56) $ (0.67) $ 1.15 $ 1.24 Diluted $ (0.56) $ (0.67) $ 1.14 $ 1.24 Additional information: Anti-dilutive shares 85 51 — 6

Segment Information_2

Segment Information	9 Months Ended
	Sep. 30, 2022
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	The following table presents summary financial information concerning the reportable segment and other. Three Months Ended September 30, In thousands NGD Other NW Natural Other NW Holdings 2022 Operating revenues $ 103,295 $ 7,131 $ 110,426 $ 6,413 $ 116,839 Depreciation 27,937 264 28,201 825 29,026 Income (loss) from operations (20,910) 5,616 (15,294) 367 (14,927) Net income (loss) (23,016) 4,210 (18,806) (781) (19,587) Capital expenditures 79,847 431 80,278 3,868 84,146 2021 Operating revenues $ 91,042 $ 4,994 $ 96,036 $ 5,411 $ 101,447 Depreciation 27,462 257 27,719 719 28,438 Income (loss) from operations (18,288) 3,203 (15,085) 694 (14,391) Net income (loss) (23,297) 2,279 (21,018) 363 (20,655) Capital expenditures 72,822 1,410 74,232 8,036 82,268 Nine Months Ended September 30, In thousands NGD Other NW Natural Other NW Holdings 2022 Operating revenues $ 629,327 $ 17,974 $ 647,301 $ 14,799 $ 662,100 Depreciation 82,372 794 83,166 2,399 85,565 Income (loss) from operations 75,328 12,054 87,382 (1,132) 86,250 Net income (loss) 32,531 8,812 41,343 (2,976) 38,367 Capital expenditures 235,249 1,218 236,467 15,375 251,842 Total assets at September 30, 2022 3,968,040 56,712 4,024,752 275,960 4,300,712 2021 Operating revenues $ 531,994 $ 20,971 $ 552,965 $ 13,345 $ 566,310 Depreciation 81,648 770 82,418 2,261 84,679 Income (loss) from operations 79,530 14,642 94,172 (1,233) 92,939 Net income (loss) 29,247 10,435 39,682 (1,544) 38,138 Capital expenditures 197,190 2,209 199,399 12,977 212,376 Total assets at September 30, 2021 3,730,595 50,366 3,780,961 148,264 3,929,225 Total assets at December 31, 2021 3,846,112 52,260 3,898,372 166,232 4,064,604
NGD Margin	The following table presents additional segment information concerning NGD margin: Three Months Ended September 30, Nine Months Ended September 30, In thousands 2022 2021 2022 2021 NGD margin calculation: NGD distribution revenues $ 98,391 $ 86,271 $ 614,605 $ 517,673 Other regulated services 4,904 4,771 14,722 14,321 Total NGD operating revenues 103,295 91,042 629,327 531,994 Less: NGD cost of gas 36,258 25,322 261,678 178,837 Environmental remediation 975 806 7,945 6,092 Revenue taxes 4,375 3,838 25,907 22,143 NGD margin $ 61,687 $ 61,076 $ 333,797 $ 324,922

Revenue_2

Revenue	3 Months Ended
	Sep. 30, 2022
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following tables present disaggregated revenue: Three Months Ended September 30, In thousands NGD Other NW Natural Other NW Holdings 2022 Natural gas sales $ 95,784 $ — $ 95,784 $ — $ 95,784 Gas storage revenue, net — 2,882 2,882 — 2,882 Asset management revenue, net — 3,047 3,047 — 3,047 Appliance retail center revenue — 1,202 1,202 — 1,202 Other revenue 624 — 624 6,413 7,037 Revenue from contracts with customers 96,408 7,131 103,539 6,413 109,952 Alternative revenue 2,589 — 2,589 — 2,589 Leasing revenue 4,298 — 4,298 — 4,298 Total operating revenues $ 103,295 $ 7,131 $ 110,426 $ 6,413 $ 116,839 2021 Natural gas sales $ 83,947 $ — $ 83,947 $ — $ 83,947 Gas storage revenue, net — 2,794 2,794 — 2,794 Asset management revenue, net — 1,012 1,012 — 1,012 Appliance retail center revenue — 1,188 1,188 — 1,188 Other revenue 403 — 403 5,411 5,814 Revenue from contracts with customers 84,350 4,994 89,344 5,411 94,755 Alternative revenue 2,307 — 2,307 — 2,307 Leasing revenue 4,385 — 4,385 — 4,385 Total operating revenues $ 91,042 $ 4,994 $ 96,036 $ 5,411 $ 101,447 Nine Months Ended September 30, In thousands NGD Other NW Natural Other NW Holdings 2022 Natural gas sales $ 623,121 $ — $ 623,121 $ — $ 623,121 Gas storage revenue, net — 8,678 8,678 — 8,678 Asset management revenue, net — 4,941 4,941 — 4,941 Appliance retail center revenue — 4,355 4,355 — 4,355 Other revenue 1,882 — 1,882 14,799 16,681 Revenue from contracts with customers 625,003 17,974 642,977 14,799 657,776 Alternative revenue (8,571) — (8,571) — (8,571) Leasing revenue 12,895 — 12,895 — 12,895 Total operating revenues $ 629,327 $ 17,974 $ 647,301 $ 14,799 $ 662,100 2021 Natural gas sales $ 503,769 $ — $ 503,769 $ — $ 503,769 Gas storage revenue, net — 8,094 8,094 — 8,094 Asset management revenue, net — 8,757 8,757 — 8,757 Appliance retail center revenue — 4,120 4,120 — 4,120 Other revenue 1,217 — 1,217 13,345 14,562 Revenue from contracts with customers 504,986 20,971 525,957 13,345 539,302 Alternative revenue 13,843 — 13,843 — 13,843 Leasing revenue 13,165 — 13,165 — 13,165 Total operating revenues $ 531,994 $ 20,971 $ 552,965 $ 13,345 $ 566,310

Leases_2

Leases	9 Months Ended
	Sep. 30, 2022
Leases [Abstract]
Lease Revenue	The components of lease revenue at NW Natural were as follows: Three Months Ended September 30, Nine Months Ended September 30, In thousands 2022 2021 2022 2021 Lease revenue Operating leases $ 19 $ 18 $ 56 $ 61 Sales-type leases 4,279 4,367 12,839 13,104 Total lease revenue $ 4,298 $ 4,385 $ 12,895 $ 13,165
Lessor, Operating Lease, Payments to be Received, Maturity	Total future minimum lease payments to be received under non-cancelable leases at September 30, 2022 are as follows: In thousands Operating Sales-Type Total NW Natural: Remainder of 2022 $ 145 $ 4,217 $ 4,362 2023 76 16,557 16,633 2024 76 15,867 15,943 2025 67 15,306 15,373 2026 36 14,901 14,937 Thereafter 22 236,820 236,842 Total minimum lease payments $ 422 $ 303,668 $ 304,090 Less: imputed interest 168,188 Total leases receivable $ 135,480 Other (NW Holdings): Remainder of 2022 $ 13 $ — $ 13 2023 51 — 51 2024 52 — 52 2025 53 — 53 2026 56 — 56 Thereafter 914 — 914 Total minimum lease payments $ 1,139 $ — $ 1,139 NW Holdings: Remainder of 2022 $ 158 $ 4,217 $ 4,375 2023 127 16,557 16,684 2024 128 15,867 15,995 2025 120 15,306 15,426 2026 92 14,901 14,993 Thereafter 936 236,820 237,756 Total minimum lease payments $ 1,561 $ 303,668 $ 305,229 Less: imputed interest 168,188 Total leases receivable $ 135,480
Lease Expense	The components of lease expense, a portion of which is capitalized, were as follows: Three Months Ended September 30, Nine Months Ended September 30, In thousands 2022 2021 2022 2021 NW Natural: Operating lease expense $ 1,767 $ 1,735 $ 5,235 $ 5,123 Short-term lease expense $ 105 $ 499 $ 684 $ 1,068 Other (NW Holdings): Operating lease expense $ 7 $ 14 $ 22 $ 50 NW Holdings: Operating lease expense $ 1,774 $ 1,749 $ 5,257 $ 5,173 Short-term lease expense $ 105 $ 499 $ 684 $ 1,068
Operating Lease, Lease Asset and Liabilities	Supplemental balance sheet information related to operating leases as of September 30, 2022 and 2021 and December 31, 2021 is as follows: In thousands September 30, December 31, 2022 2021 2021 NW Natural: Operating lease right of use asset $ 73,046 $ 75,565 $ 74,987 Operating lease liabilities - current liabilities $ 1,298 $ 1,184 $ 1,273 Operating lease liabilities - non-current liabilities 78,436 79,752 79,431 Total operating lease liabilities $ 79,734 $ 80,936 $ 80,704 Other (NW Holdings): Operating lease right of use asset $ 99 $ 69 $ 62 Operating lease liabilities - current liabilities $ 63 $ 29 $ 23 Operating lease liabilities - non-current liabilities 33 37 37 Total operating lease liabilities $ 96 $ 66 $ 60 NW Holdings: Operating lease right of use asset $ 73,145 $ 75,634 $ 75,049 Operating lease liabilities - current liabilities $ 1,361 $ 1,213 $ 1,296 Operating lease liabilities - non-current liabilities 78,469 79,789 79,468 Total operating lease liabilities $ 79,830 $ 81,002 $ 80,764
Operating Lease, Weighted Average Remaining Term and Discount Rates [Table Text Block]	The weighted-average remaining lease terms and weighted-average discount rates for the operating leases at NW Natural were as follows: In thousands September 30, December 31, 2022 2021 2021 Weighted-average remaining lease term (years) 17.5 18.4 18.2 Weighted-average discount rate 7.3 % 7.2 % 7.2 %
Lessee, Operating Lease, Liability, Maturity	Maturities of operating lease liabilities at September 30, 2022 were as follows: In thousands NW Natural Other NW Holdings Remainder of 2022 $ 1,752 $ 8 $ 1,760 2023 7,046 26 7,072 2024 7,183 27 7,210 2025 7,185 20 7,205 2026 7,353 6 7,359 Thereafter 116,431 18 116,449 Total lease payments 146,950 105 147,055 Less: imputed interest 67,216 9 67,225 Total lease obligations 79,734 96 79,830 Less: current obligations 1,298 63 1,361 Long-term lease obligations $ 78,436 $ 33 $ 78,469
Lessee, Leases, Supplemental Cash Flow Information	Supplemental cash flow information related to leases was as follows: Three Months Ended September 30, Nine Months Ended September 30, In thousands 2022 2021 2022 2021 NW Natural: Cash paid for amounts included in the measurement of lease liabilities Operating cash flows from operating leases $ 1,759 $ 1,727 $ 5,225 $ 5,113 Finance cash flows from finance leases $ 92 $ 123 $ 474 $ 801 Right of use assets obtained in exchange for lease obligations Operating leases $ — $ — $ — $ 154 Finance leases $ 6 $ 75 $ 226 $ 169 Other (NW Holdings): Cash paid for amounts included in the measurement of lease liabilities Operating cash flows from operating leases $ 12 $ 18 $ 24 $ 51 Right of use assets obtained in exchange for lease obligations Operating leases $ 61 $ — $ 61 $ — NW Holdings: Cash paid for amounts included in the measurement of lease liabilities Operating cash flows from operating leases $ 1,771 $ 1,745 $ 5,249 $ 5,164 Finance cash flows from finance leases $ 92 $ 123 $ 474 $ 801 Right of use assets obtained in exchange for lease obligations Operating leases $ 61 $ — $ 61 $ 154 Finance leases $ 6 $ 75 $ 226 $ 169

Debt_2

Debt	9 Months Ended
	Sep. 30, 2022
Debt Disclosure [Abstract]
Schedule of Carrying Values and Estimated Fair Values of Debt Instruments	The following table provides an estimate of the fair value of long-term debt, including current maturities of long-term debt, using market prices in effect on the valuation date: September 30, December 31, In thousands 2022 2021 2021 NW Natural: Gross long-term debt $ 1,134,700 $ 864,700 $ 994,700 Unamortized debt issuance costs (8,229) (6,940) (8,205) Carrying amount $ 1,126,471 $ 857,760 $ 986,495 Estimated fair value (1) $ 927,372 $ 978,613 $ 1,110,741 NW Holdings: Gross long-term debt $ 1,345,968 $ 923,355 $ 1,053,241 Unamortized debt issuance costs (8,348) (7,051) (8,309) Carrying amount $ 1,337,620 $ 916,304 $ 1,044,932 Estimated fair value (1) $ 1,133,087 $ 1,042,705 $ 1,174,500 (1) Estimated fair value does not include unamortized debt issuance costs.

Pension and Other Postretirem_2

Pension and Other Postretirement Benefit Costs	9 Months Ended
	Sep. 30, 2022
Pension and Other Postretirement Benefits Cost (Reversal of Cost) [Abstract]
Schedule of Net Benefit Costs	The following table provides the components of net periodic benefit cost (credit) for the pension and other postretirement benefit plans: Three Months Ended September 30, Nine Months Ended September 30, Pension Benefits Other Postretirement Pension Benefits Other In thousands 2022 2021 2022 2021 2022 2021 2022 2021 Service cost $ 1,022 $ 1,717 $ 34 $ 69 $ 4,450 $ 5,145 $ 145 $ 180 Interest cost 4,260 3,316 213 180 10,945 10,001 543 510 Expected return on plan assets (7,076) (5,802) — — (19,274) (18,000) — — Amortization of prior service credit — — (15) (119) — — (249) (353) Amortization of net actuarial loss (1,542) 5,515 57 226 9,459 16,516 319 488 Net periodic benefit cost (credit) (3,336) 4,746 289 356 5,580 13,662 758 825 Amount allocated to construction (496) (759) (14) (27) (1,965) (2,228) (57) (70) Net periodic benefit cost (credit) charged to expense (3,832) 3,987 275 329 3,615 11,434 701 755 Amortization of regulatory balancing account 675 675 — — 4,757 4,757 — — Net amount charged to expense $ (3,157) $ 4,662 $ 275 $ 329 $ 8,372 $ 16,191 $ 701 $ 755
Schedule of Amounts Recognized in Other Comprehensive Income (Loss)	The following table presents amounts recognized in accumulated other comprehensive loss (AOCL) and the changes in AOCL related to non-qualified employee benefit plans: Three Months Ended September 30, Nine Months Ended September 30, In thousands 2022 2021 2022 2021 Beginning balance $ (11,010) $ (12,460) $ (11,404) $ (12,902) Amounts reclassified from AOCL: Amortization of actuarial losses 275 314 811 916 Total reclassifications before tax 275 314 811 916 Tax benefit (73) (80) (215) (240) Total reclassifications for the period 202 234 596 676 Ending balance $ (10,808) $ (12,226) $ (10,808) $ (12,226)

Income Tax_2

Income Tax	9 Months Ended
	Sep. 30, 2022
Income Tax Disclosure [Abstract]
Schedule of Effective Income Tax Rate Reconciliation	The effective income tax rate varied from the federal statutory rate due to the following: Three Months Ended September 30, NW Holdings NW Natural In thousands 2022 2021 2022 2021 Income tax at statutory rate (federal) $ (5,533) $ (5,834) $ (5,305) $ (5,928) State income tax (2,376) (2,599) (2,306) (2,618) Increase (decrease): Differences required to be flowed-through by regulatory commissions 1,232 1,318 1,232 1,318 Other, net (81) (12) (76) 16 Total provision for income taxes $ (6,758) $ (7,127) $ (6,455) $ (7,212) Effective income tax rate 25.7 % 25.7 % 25.6 % 25.5 % Nine Months Ended September 30, NW Holdings NW Natural In thousands 2022 2021 2022 2021 Income tax at statutory rate (federal) $ 10,710 $ 10,764 $ 11,554 $ 11,195 State income tax 4,298 4,660 4,497 4,748 Increase (decrease): Differences required to be flowed-through by regulatory commissions (2,003) (2,266) (2,003) (2,266) Other, net (370) (41) (370) (49) Total provision for income taxes $ 12,635 $ 13,117 $ 13,678 $ 13,628 Effective income tax rate 24.8 % 25.6 % 24.9 % 25.6 %

Property, Plant and Equipment_2

Property, Plant and Equipment	9 Months Ended
	Sep. 30, 2022
Property, Plant and Equipment [Abstract]
Public Utility Property, Plant, and Equipment [Table Text Block]	The following table sets forth the major classifications of property, plant, and equipment and accumulated depreciation: September 30, December 31, In thousands 2022 2021 2021 NW Natural: NGD plant in service $ 3,888,092 $ 3,663,699 $ 3,721,939 NGD construction work in progress 161,658 120,412 135,398 Less: Accumulated depreciation 1,135,965 1,086,510 1,098,715 NGD plant, net 2,913,785 2,697,601 2,758,622 Other plant in service 69,626 66,314 69,332 Other construction work in progress 5,112 7,228 4,971 Less: Accumulated depreciation 21,435 20,392 20,646 Other plant, net 53,303 53,150 53,657 Total property, plant, and equipment, net $ 2,967,088 $ 2,750,751 $ 2,812,279 Other (NW Holdings): Other plant in service $ 66,208 $ 53,175 $ 57,184 Other construction work in progress 16,632 8,268 8,419 Less: Accumulated depreciation 8,750 5,832 6,512 Other plant, net $ 74,090 $ 55,611 $ 59,091 NW Holdings: Total property, plant, and equipment, net $ 3,041,178 $ 2,806,362 $ 2,871,370 NW Natural: Capital expenditures in accrued liabilities $ 43,954 $ 33,968 $ 37,537 NW Holdings: Capital expenditures in accrued liabilities $ 45,374 $ 35,955 $ 38,333 NW Natural Other plant balances include non-utility gas storage assets at the Mist facility and other long-lived assets not related to NGD. NW Holdings Other plant balances include long-lived assets associated with water and wastewater operations and non-regulated activities not held by NW Natural or its subsidiaries.

Investments_2

Investments	9 Months Ended
	Sep. 30, 2022
Investments [Abstract]
Investment [Table Text Block]	Investments include gas reserves, financial investments in life insurance policies, and equity method investments. The following table summarizes other investments: NW Holdings NW Natural September 30, December 31, September 30, December 31, In thousands 2022 2021 2021 2022 2021 2021 Investments in life insurance policies $ 49,043 $ 47,970 $ 48,178 $ 49,043 $ 47,970 $ 48,178 Investments in gas reserves, non-current 23,770 28,021 26,608 23,770 28,021 26,608 Investment in unconsolidated affiliates 23,756 36 14,492 8,058 — — Total other investments $ 96,569 $ 76,027 $ 89,278 $ 80,871 $ 75,991 $ 74,786

Derivative Instruments_2

Derivative Instruments	9 Months Ended
	Sep. 30, 2022
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Notional Amounts of Outstanding Derivative Positions	The following table presents the absolute notional amounts related to open positions on NW Natural derivative instruments: September 30, December 31, In thousands 2022 2021 2021 Natural gas (in therms): Financial 1,006,665 749,595 618,815 Physical 672,350 613,524 431,628 Foreign exchange $ 9,905 $ 6,299 $ 6,268
Income Statement Presentation of Derivative Instruments	The following table reflects the income statement presentation for the unrealized gains and losses from NW Natural's derivative instruments, which also represents all derivative instruments at NW Holdings: Three Months Ended September 30, 2022 2021 In thousands Natural gas commodity Foreign exchange Natural gas commodity Foreign exchange Benefit (expense) to cost of gas $ (11,626) $ (455) $ 69,239 $ (106) Operating revenues (expense) — — — — Amounts deferred to regulatory accounts on balance sheet 11,626 455 (69,239) 106 Total gain (loss) in pre-tax earnings $ — $ — $ — $ —

Environmental Matters_2

Environmental Matters	9 Months Ended
	Sep. 30, 2022
Environmental Remediation Obligations [Abstract]
Schedule of Environmental Loss Contingencies by Site	The following table summarizes information regarding liabilities related to environmental sites, which are recorded in other current liabilities and other noncurrent liabilities in NW Natural's balance sheet: Current Liabilities Non-Current Liabilities September 30, December 31, September 30, December 31, In thousands 2022 2021 2021 2022 2021 2021 Portland Harbor site: Gasco/Siltronic Sediments $ 5,556 $ 6,925 $ 7,582 $ 40,740 $ 40,929 $ 42,076 Other Portland Harbor 2,430 2,392 2,592 8,135 6,222 9,570 Gasco/Siltronic Upland site 8,367 9,720 15,711 33,354 37,408 36,215 Front Street site 201 1,002 1,100 868 893 811 Oregon Steel Mills — — — 179 179 179 Total $ 16,554 $ 20,039 $ 26,985 $ 83,276 $ 85,631 $ 88,851
Environmental Regulatory Table	The following table presents information regarding the total regulatory asset deferred: September 30, December 31, In thousands 2022 2021 2021 Deferred costs and interest (1) $ 47,011 $ 45,019 $ 45,122 Accrued site liabilities (2) 99,795 105,607 115,773 Insurance proceeds and interest (54,678) (59,589) (59,564) Total regulatory asset deferral (1) $ 92,128 $ 91,037 $ 101,331 Current regulatory assets (3) 9,461 7,068 6,694 Long-term regulatory assets (3) 82,667 83,969 94,636 (1) Includes pre-review and post-review deferred costs, amounts currently in amortization, and interest, net of amounts collected from customers. (2) Exclude s 3.3% of the Front Street site liability as the OPUC only allows recovery of 96.7% of costs for those sites allocable to Oregon, including those that historically served only Oregon customers. Amounts excluded from regulatory assets were $34 thousand at September 30, 2022, $62 thousand at September 30, 2021, and $62 thousand at December 31, 2021. (3) Environmental costs relate to specific sites approved for regulatory deferral by the OPUC and WUTC. In Oregon, NW Natural earns a carrying charge on cash amounts paid, whereas amounts accrued but not yet paid do not earn a carrying charge until expended. It also accrues a carrying charge on insurance proceeds for amounts owed to customers. In Washington, neither the cash paid for insurance proceeds received accrue a carrying charge. Current environmental costs represent remediation costs management expects to collect from customers in the next 12 months. Amounts included in this estimate are still subject to a prudence and earnings test review by the OPUC and do not include the $5.0 million tariff rider. The amounts allocable to Oregon are recoverable through NGD rates, subject to an earnings test.

Significant Accounting Polici_4

Significant Accounting Policies - Regulatory Asset Disclosure - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021	Sep. 30, 2021
Regulatory Assets [Line Items]
Regulatory Assets, Current	$ 104,830	$ 72,391	$ 80,638
Regulatory Assets, Noncurrent	301,660	314,579	325,071
Other [Member]
Regulatory Assets [Line Items]
Regulatory Assets, Noncurrent	64	40	40
Northwest Natural Gas Company [Member]
Regulatory Assets [Line Items]
Regulatory Assets, Current	104,830	72,391	80,638
Regulatory Assets, Noncurrent	301,596	314,539	325,031
Northwest Natural Gas Company [Member] | Deferred Derivative Gain (Loss) [Member]
Regulatory Assets [Line Items]
Regulatory Assets, Current	19,594	10,402	9,818
Regulatory Assets, Noncurrent	18,824	412	268
Northwest Natural Gas Company [Member] | Gas costs [Member]
Regulatory Assets [Line Items]
Regulatory Assets, Current	52,115	35,641	39,622
Regulatory Assets, Noncurrent	3,369	15,477	2,858
Northwest Natural Gas Company [Member] | Environmental costs [Member]
Regulatory Assets [Line Items]
Regulatory Assets, Current	9,461	6,694	7,068
Regulatory Assets, Noncurrent	82,667	94,636	83,969
Northwest Natural Gas Company [Member] | Decoupling [Member]
Regulatory Assets [Line Items]
Regulatory Assets, Current	114	969	1,628
Regulatory Assets, Noncurrent	0	0	118
Northwest Natural Gas Company [Member] | Pension balancing [Member]
Regulatory Assets [Line Items]
Regulatory Assets, Current	7,131	7,131	7,131
Regulatory Assets, Noncurrent	34,928	38,302	40,176
Northwest Natural Gas Company [Member] | Income taxes [Member]
Regulatory Assets [Line Items]
Regulatory Assets, Current	2,399	2,568	2,939
Regulatory Assets, Noncurrent	11,168	12,609	13,912
Northwest Natural Gas Company [Member] | Pension and other postretirement benefit liabilities [Member]
Regulatory Assets [Line Items]
Regulatory Assets, Noncurrent	107,722	116,440	155,077
Northwest Natural Gas Company [Member] | Other [Member]
Regulatory Assets [Line Items]
Regulatory Assets, Current	14,016	8,986	12,432
Regulatory Assets, Noncurrent	$ 42,918	$ 36,663	$ 28,653

Significant Accounting Polici_5

Significant Accounting Policies - Regulatory Liability Disclosure - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021	Sep. 30, 2021
Regulatory Liabilities [Line Items]
Regulatory Liability, Current	$ 111,551	$ 112,281	$ 164,168
Regulatory Liability, Noncurrent	663,547	658,332	665,390
Other [Member]
Regulatory Liabilities [Line Items]
Regulatory Liability, Current	25	0	0
Regulatory Liability, Noncurrent	982	982	869
Northwest Natural Gas Company [Member]
Regulatory Liabilities [Line Items]
Regulatory Liability, Current	111,526	112,281	164,168
Regulatory Liability, Noncurrent	662,565	657,350	664,521
Northwest Natural Gas Company [Member] | Gas costs [Member]
Regulatory Liabilities [Line Items]
Regulatory Liability, Current	944	70	847
Regulatory Liability, Noncurrent	50	250	0
Northwest Natural Gas Company [Member] | Deferred Derivative Gain (Loss) [Member]
Regulatory Liabilities [Line Items]
Regulatory Liability, Current	62,882	48,130	105,175
Regulatory Liability, Noncurrent	8,008	10,730	24,555
Northwest Natural Gas Company [Member] | Decoupling [Member]
Regulatory Liabilities [Line Items]
Regulatory Liability, Current	13,272	4,475	4,484
Regulatory Liability, Noncurrent	884	3,412	214
Northwest Natural Gas Company [Member] | Income taxes [Member]
Regulatory Liabilities [Line Items]
Regulatory Liability, Current	7,318	8,192	8,217
Regulatory Liability, Noncurrent	179,319	181,404	186,429
Northwest Natural Gas Company [Member] | Other [Member]
Regulatory Liabilities [Line Items]
Regulatory Liability, Current	3,649	6,290	1,562
Regulatory Liability, Noncurrent	13,638	13,792	12,913
Northwest Natural Gas Company [Member] | Accrued asset removal costs [Member]
Regulatory Liabilities [Line Items]
Regulatory Liability, Noncurrent	460,666	445,952	440,410
Northwest Natural Gas Company [Member] | Asset Optimization Revenue Sharing
Regulatory Liabilities [Line Items]
Regulatory Liability, Current	23,461	45,124	43,883
Regulatory Liability, Noncurrent	$ 0	$ 1,810	$ 0

Supplemental Cash Flow

Supplemental Cash Flow - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021	Sep. 30, 2021	Dec. 31, 2020
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	$ 108,556	$ 18,559	$ 19,502
Restricted Cash	11,714	8,561	8,170
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	120,270	27,120	27,672	$ 35,454
Northwest Natural Gas Company [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	11,386	12,271	9,697
Restricted Cash	11,714	8,561	8,170
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 23,100	$ 20,832	$ 17,867	$ 15,739

Significant Accounting Polici_6

Significant Accounting Policies - Credit Losses - ASU 2016-13 $ in Thousands	9 Months Ended
	Sep. 30, 2022 USD ($) numberOfLeases	Dec. 31, 2021 USD ($)	Sep. 30, 2021 USD ($)
Accounts Receivable, Noncurrent, Credit Quality Indicator [Line Items]
Accounts Receivable, Allowance for Credit Loss	$ 2,171	$ 2,018
Accounts Receivable, Allowance for Credit Loss, Period Increase (Decrease)	1,528
Accounts Receivable, Allowance for Credit Loss, Recovery	$ (1,375)
Number of Net Investments in Sales-Type Leases | numberOfLeases	2
Sales-type Lease, Net Investment in Lease, Allowance for Credit Loss	$ 0
Regulatory Assets, Noncurrent	301,660	314,579	$ 325,071
COVID-19 Related Costs
Accounts Receivable, Noncurrent, Credit Quality Indicator [Line Items]
Regulatory Assets, Noncurrent	15,100		$ 7,400
Portion of COVID-19 Cost Approved for Recovery in 2022 OR Rate Case
Accounts Receivable, Noncurrent, Credit Quality Indicator [Line Items]
Regulatory Assets, Noncurrent	$ 10,900
Regulatory Asset, Amortization Period	2 years
Residential [Member]
Accounts Receivable, Noncurrent, Credit Quality Indicator [Line Items]
Accounts Receivable, Allowance for Credit Loss	$ 1,485	1,460
Accounts Receivable, Allowance for Credit Loss, Period Increase (Decrease)	896
Accounts Receivable, Allowance for Credit Loss, Recovery	(871)
Commercial [Member]
Accounts Receivable, Noncurrent, Credit Quality Indicator [Line Items]
Accounts Receivable, Allowance for Credit Loss	281	178
Accounts Receivable, Allowance for Credit Loss, Period Increase (Decrease)	375
Accounts Receivable, Allowance for Credit Loss, Recovery	(272)
Industrial [Member]
Accounts Receivable, Noncurrent, Credit Quality Indicator [Line Items]
Accounts Receivable, Allowance for Credit Loss	178	67
Accounts Receivable, Allowance for Credit Loss, Period Increase (Decrease)	173
Accounts Receivable, Allowance for Credit Loss, Recovery	(62)
Accrued unbilled and other [Member]
Accounts Receivable, Noncurrent, Credit Quality Indicator [Line Items]
Accounts Receivable, Allowance for Credit Loss	227	$ 313
Accounts Receivable, Allowance for Credit Loss, Period Increase (Decrease)	84
Accounts Receivable, Allowance for Credit Loss, Recovery	$ (170)

Earnings Per Share_2_3

Earnings Per Share - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Earnings Per Share [Abstract]
Net income	$ (19,587)	$ (20,655)	$ 38,367	$ 38,138
Average common shares outstanding:
Average common shares outstanding - basic (in shares)	34,939	30,696	33,491	30,659
Additional shares for stock-based compensation plans	0	0	48	49
Average common shares outstanding - diluted (in shares)	34,939	30,696	33,539	30,708
Earnings (loss) per share of common stock
Basic (in dollars per share)	$ (0.56)	$ (0.67)	$ 1.15	$ 1.24
Diluted (in dollars per share)	$ (0.56)	$ (0.67)	$ 1.14	$ 1.24
Antidilutive shares	85	51	0	6

Segment Information - Narrative

Segment Information - Narrative	9 Months Ended
	Sep. 30, 2022
Operating Segments [Member]
Segment Reporting Information [Line Items]
Number of Reportable Segments	1
Oregon [Member] | Northwest Holdings and Northwest Natural [Member] | Natural Gas Distribution [Member]
Segment Reporting Information [Line Items]
Percent Of Pre Tax Income From Gas Storage Retained When The Costs Of The Capacity Are Not In Utility Rates	80%
Percent Of Pre Tax Income From Gas Storage Retained When The Costs Of The Capacity Are In Utility Rates	10%
Percent Of Pre Tax Income From Gas Storage Credited To Deferred Regulatory Account	20%
Percent Of Pre Tax Income From Gas Storage Credited To Deferred Regulatory Account When In Rates	90%

Segment Information - Schedule

Segment Information - Schedule of Summarized Financial Information by Segment - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Segment Reporting Information [Line Items]
Operating revenues	$ 116,839	$ 101,447	$ 662,100	$ 566,310
Depreciation	29,026	28,438	85,565	84,679
Income from operations	(14,927)	(14,391)	86,250	92,939
Total assets	4,300,712	3,929,225	4,300,712	3,929,225	$ 4,064,604
Natural Gas Distribution [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	103,295	91,042	629,327	531,994
Depreciation	27,937	27,462	82,372	81,648
Income from operations	(20,910)	(18,288)	75,328	79,530
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	(23,016)	(23,297)	32,531	29,247
Capital expenditures	79,847	72,822	235,249	197,190
Total assets	3,968,040	3,730,595	3,968,040	3,730,595	3,846,112
Other Northwest Natural [Member] | Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Operating revenues	7,131	4,994	17,974	20,971
Depreciation	264	257	794	770
Income from operations	5,616	3,203	12,054	14,642
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	4,210	2,279	8,812	10,435
Capital expenditures	431	1,410	1,218	2,209
Total assets	56,712	50,366	56,712	50,366	52,260
Northwest Natural Gas Company [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	110,426	96,036	647,301	552,965
Depreciation	28,201	27,719	83,166	82,418
Income from operations	(15,294)	(15,085)	87,382	94,172
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	(18,806)	(21,018)	41,343	39,682
Capital expenditures	80,278	74,232	236,467	199,399
Total assets	4,024,752	3,780,961	4,024,752	3,780,961	3,898,372
Other Northwest Holdings [Member] | Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Operating revenues	6,413	5,411	14,799	13,345
Depreciation	825	719	2,399	2,261
Income from operations	367	694	(1,132)	(1,233)
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	(781)	363	(2,976)	(1,544)
Capital expenditures	3,868	8,036	15,375	12,977
Total assets	275,960	148,264	275,960	148,264	166,232
Northwest Natural Gas Company [Member]
Segment Reporting Information [Line Items]
Operating revenues	110,426	96,036	647,301	552,965
Depreciation	28,201	27,719	83,166	82,418
Income from operations	(15,294)	(15,085)	87,382	94,172
Total assets	4,024,752	3,780,961	4,024,752	3,780,961	3,898,372
Northwest Natural Gas Company [Member] | Natural Gas Distribution [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	103,295	91,042	629,327	531,994
Northwest Natural Gas Company [Member] | Other Northwest Natural [Member] | Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Operating revenues	7,131	4,994	17,974	20,971
Northwest Natural Gas Company [Member] | Northwest Natural Gas Company [Member]
Segment Reporting Information [Line Items]
Operating revenues	110,426	96,036	647,301	552,965
Parent Company [Member]
Segment Reporting Information [Line Items]
Operating revenues	116,839	101,447	662,100	566,310
Depreciation	29,026	28,438	85,565	84,679
Income from operations	(14,927)	(14,391)	86,250	92,939
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	(19,587)	(20,655)	38,367	38,138
Capital expenditures	84,146	82,268	251,842	212,376
Total assets	$ 4,300,712	$ 3,929,225	$ 4,300,712	$ 3,929,225	$ 4,064,604

Segment Information - Additiona

Segment Information - Additional Segment Information - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Segment Reporting Information [Line Items]
Operating revenues	$ 116,839	$ 101,447	$ 662,100	$ 566,310
Cost of gas	36,105	25,266	261,413	178,669
Environmental remediation	980	806	7,950	6,092
Operating Segments [Member] | Natural Gas Distribution [Member]
Segment Reporting Information [Line Items]
Natural Gas Distribution revenues	98,391	86,271	614,605	517,673
Other regulated services	4,904	4,771	14,722	14,321
Operating revenues	103,295	91,042	629,327	531,994
Cost of gas	36,258	25,322	261,678	178,837
Environmental remediation	975	806	7,945	6,092
Revenue taxes	4,375	3,838	25,907	22,143
NGD margin	$ 61,687	$ 61,076	$ 333,797	$ 324,922

Equity - Narrative

Equity - Narrative - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended	9 Months Ended
	Apr. 01, 2022	Sep. 30, 2022	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Class of Stock [Line Items]
Par Value (in dollars per share)		$ 0	$ 0	$ 0	$ 0
Shares issued (in shares)		35,098,000	35,098,000	30,730,000	31,129,000
Stock Issued During Period, Shares, New Issues	2,875,000
Proceeds from common stock issued, net	$ 138,600		$ 190,929	$ 2,107
Avion Water | Other Northwest Holdings [Member]
Class of Stock [Line Items]
Investment balance in Avion					$ 14,500
Northwest Natural Gas Company [Member]
Class of Stock [Line Items]
Repayments of Short-term Debt	$ 130,000
ATM Equity Program
Class of Stock [Line Items]
Par Value (in dollars per share)		$ 0	$ 0
Sale of Stock, Consideration Received on Transaction		$ 16,700	$ 51,900
Sale of Stock, Commissions and Fees Paid		$ 300	$ 1,000
Stock Issued During Period, Shares, New Issues		327,221	1,005,322
nwn:AttheMarketEquityProgramEquityAvailableforIssuance		$ 129,200	$ 129,200
Maximum [Member] | Scenario, Plan | ATM Equity Program
Class of Stock [Line Items]
Cumulative Proceeds Received on All Transactions			$ 200,000

Revenue - Disaggregation of Rev

Revenue - Disaggregation of Revenue - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	$ 109,952	$ 94,755	$ 657,776	$ 539,302
Revenues	116,839	101,447	662,100	566,310
Natural Gas Sales [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	95,784	83,947	623,121	503,769
Gas Storage Revenue, Net of Regulatory Sharing [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	2,882	2,794	8,678	8,094
Asset Management Revenue, Net of Regulatory Sharing [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	3,047	1,012	4,941	8,757
Appliance Center Revenue [Member] | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	1,202	1,188	4,355	4,120
Other revenue [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	7,037	5,814	16,681	14,562
Alternative revenue [Member]
Disaggregation of Revenue [Line Items]
Revenues	2,589	2,307	(8,571)	13,843
Leasing revenue [Member]
Disaggregation of Revenue [Line Items]
Operating leases	4,298	4,385	12,895	13,165
Northwest Natural Gas Company [Member]
Disaggregation of Revenue [Line Items]
Revenues	110,426	96,036	647,301	552,965
Operating leases	19	18	56	61
Northwest Natural Gas Company [Member] | Northwest Natural Gas Company [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	103,539	89,344	642,977	525,957
Revenues	110,426	96,036	647,301	552,965
Northwest Natural Gas Company [Member] | Northwest Natural Gas Company [Member] | Natural Gas Sales [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	95,784	83,947	623,121	503,769
Northwest Natural Gas Company [Member] | Northwest Natural Gas Company [Member] | Gas Storage Revenue, Net of Regulatory Sharing [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	2,882	2,794	8,678	8,094
Northwest Natural Gas Company [Member] | Northwest Natural Gas Company [Member] | Asset Management Revenue, Net of Regulatory Sharing [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	3,047	1,012	4,941	8,757
Northwest Natural Gas Company [Member] | Northwest Natural Gas Company [Member] | Appliance Center Revenue [Member] | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	1,202	1,188	4,355	4,120
Northwest Natural Gas Company [Member] | Northwest Natural Gas Company [Member] | Other revenue [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	624	403	1,882	1,217
Northwest Natural Gas Company [Member] | Northwest Natural Gas Company [Member] | Alternative revenue [Member]
Disaggregation of Revenue [Line Items]
Revenues	2,589	2,307	(8,571)	13,843
Northwest Natural Gas Company [Member] | Northwest Natural Gas Company [Member] | Leasing revenue [Member]
Disaggregation of Revenue [Line Items]
Operating leases	4,298	4,385	12,895	13,165
Operating Segments [Member] | Natural Gas Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenues	103,295	91,042	629,327	531,994
Operating Segments [Member] | Natural Gas Distribution [Member] | Northwest Natural Gas Company [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	96,408	84,350	625,003	504,986
Revenues	103,295	91,042	629,327	531,994
Operating Segments [Member] | Natural Gas Distribution [Member] | Northwest Natural Gas Company [Member] | Natural Gas Sales [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	95,784	83,947	623,121	503,769
Operating Segments [Member] | Natural Gas Distribution [Member] | Northwest Natural Gas Company [Member] | Gas Storage Revenue, Net of Regulatory Sharing [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	0	0	0	0
Operating Segments [Member] | Natural Gas Distribution [Member] | Northwest Natural Gas Company [Member] | Asset Management Revenue, Net of Regulatory Sharing [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	0	0	0	0
Operating Segments [Member] | Natural Gas Distribution [Member] | Northwest Natural Gas Company [Member] | Appliance Center Revenue [Member] | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	0	0	0	0
Operating Segments [Member] | Natural Gas Distribution [Member] | Northwest Natural Gas Company [Member] | Other revenue [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	624	403	1,882	1,217
Operating Segments [Member] | Natural Gas Distribution [Member] | Northwest Natural Gas Company [Member] | Alternative revenue [Member]
Disaggregation of Revenue [Line Items]
Revenues	2,589	2,307	(8,571)	13,843
Operating Segments [Member] | Natural Gas Distribution [Member] | Northwest Natural Gas Company [Member] | Leasing revenue [Member]
Disaggregation of Revenue [Line Items]
Operating leases	4,298	4,385	12,895	13,165
Operating Segments [Member] | Northwest Natural Gas Company [Member]
Disaggregation of Revenue [Line Items]
Revenues	110,426	96,036	647,301	552,965
Corporate, Non-Segment [Member] | Other Northwest Natural [Member]
Disaggregation of Revenue [Line Items]
Revenues	7,131	4,994	17,974	20,971
Corporate, Non-Segment [Member] | Other Northwest Natural [Member] | Northwest Natural Gas Company [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	7,131	4,994	17,974	20,971
Revenues	7,131	4,994	17,974	20,971
Corporate, Non-Segment [Member] | Other Northwest Natural [Member] | Northwest Natural Gas Company [Member] | Natural Gas Sales [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0	0	0	0
Corporate, Non-Segment [Member] | Other Northwest Natural [Member] | Northwest Natural Gas Company [Member] | Gas Storage Revenue, Net of Regulatory Sharing [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	2,882	2,794	8,678	8,094
Corporate, Non-Segment [Member] | Other Northwest Natural [Member] | Northwest Natural Gas Company [Member] | Asset Management Revenue, Net of Regulatory Sharing [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	3,047	1,012	4,941	8,757
Corporate, Non-Segment [Member] | Other Northwest Natural [Member] | Northwest Natural Gas Company [Member] | Appliance Center Revenue [Member] | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	1,202	1,188	4,355	4,120
Corporate, Non-Segment [Member] | Other Northwest Natural [Member] | Northwest Natural Gas Company [Member] | Other revenue [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0	0	0	0
Corporate, Non-Segment [Member] | Other Northwest Natural [Member] | Northwest Natural Gas Company [Member] | Alternative revenue [Member]
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Corporate, Non-Segment [Member] | Other Northwest Natural [Member] | Northwest Natural Gas Company [Member] | Leasing revenue [Member]
Disaggregation of Revenue [Line Items]
Operating leases	0	0	0	0
Corporate, Non-Segment [Member] | Other Northwest Holdings [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	6,413	5,411	14,799	13,345
Revenues	6,413	5,411	14,799	13,345
Corporate, Non-Segment [Member] | Other Northwest Holdings [Member] | Natural Gas Sales [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0	0	0	0
Corporate, Non-Segment [Member] | Other Northwest Holdings [Member] | Gas Storage Revenue, Net of Regulatory Sharing [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0	0	0	0
Corporate, Non-Segment [Member] | Other Northwest Holdings [Member] | Asset Management Revenue, Net of Regulatory Sharing [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0	0	0	0
Corporate, Non-Segment [Member] | Other Northwest Holdings [Member] | Appliance Center Revenue [Member] | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0	0	0	0
Corporate, Non-Segment [Member] | Other Northwest Holdings [Member] | Other revenue [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	6,413	5,411	14,799	13,345
Corporate, Non-Segment [Member] | Other Northwest Holdings [Member] | Alternative revenue [Member]
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Corporate, Non-Segment [Member] | Other Northwest Holdings [Member] | Leasing revenue [Member]
Disaggregation of Revenue [Line Items]
Operating leases	$ 0	$ 0	$ 0	$ 0

Revenue - Revenue, Remaining Pe

Revenue - Revenue, Remaining Performance Obligation $ in Thousands	Sep. 30, 2022 USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Lessor, Sales-type Lease, Term of Contract	30 years
Lessor, Sales-type Lease, Renewal Term	50 years
Revenue, Remaining Performance Obligation, Amount	$ 84,400
Natural Gas Distribution [Member] | Northwest Natural Gas Company [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Contract with Customer, Refund Liability	0
Other Northwest Natural [Member] | Northwest Natural Gas Company [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Contract with Customer, Refund Liability	0
Other Northwest Holdings [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Contract with Customer, Refund Liability	$ 0
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Year	3 months
Revenue, Remaining Performance Obligation, Amount	$ 5,300
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Year	1 year
Revenue, Remaining Performance Obligation, Amount	$ 18,600
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Year	1 year
Revenue, Remaining Performance Obligation, Amount	$ 15,600
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Year	1 year
Revenue, Remaining Performance Obligation, Amount	$ 13,500
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Year	1 year
Revenue, Remaining Performance Obligation, Amount	$ 9,400
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Year	0 years
Revenue, Remaining Performance Obligation, Amount	$ 22,000

Leases - Lease Revenue

Leases - Lease Revenue - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
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	$ 5,000	$ 4,600	$ 5,000	$ 4,600	$ 4,700
Lease Revenue [Abstract]
Total lease revenue	300	100	400	400
Operating Leases Payment to be Received [Abstract]
Operating Lease, Payments to be Received, Remainder of Fiscal Year	158		158
Lessor, Operating Lease, Payment to be Received, Year One	127		127
Operating Lease, Payments to be Received, Two Years	128		128
Operating Lease, Payments to be Received, Three Years	120		120
Operating Lease, Payments to be Received, Four Years	92		92
Operating Lease, Payments to be Received, Thereafter	936		936
Total minimum lease payments	1,561		1,561
Total Lease Payments to be Received [Abstract]
Lease Payments to be Received, Remainder of Fiscal Year	4,375		4,375
Lease Payments to be Received, Two Years	16,684		16,684
Lease Payments to be Received, Three Years	15,995		15,995
Lease Payments to be Received, Four Years	15,426		15,426
Lease Payments to be Received, Five Years	14,993		14,993
Lease Payments to be Received, Thereafter	237,756		237,756
Total minimum lease payments	305,229		305,229
Northwest Natural Gas Company [Member]
Lease Revenue [Abstract]
Operating leases	19	18	56	61
Sales-type leases	4,279	4,367	12,839	13,104
Total lease revenue	4,298	$ 4,385	12,895	$ 13,165
Operating Leases Payment to be Received [Abstract]
Operating Lease, Payments to be Received, Remainder of Fiscal Year	145		145
Lessor, Operating Lease, Payment to be Received, Year One	76		76
Operating Lease, Payments to be Received, Two Years	76		76
Operating Lease, Payments to be Received, Three Years	67		67
Operating Lease, Payments to be Received, Four Years	36		36
Operating Lease, Payments to be Received, Thereafter	22		22
Total minimum lease payments	422		422
Total Lease Payments to be Received [Abstract]
Lease Payments to be Received, Remainder of Fiscal Year	4,362		4,362
Lease Payments to be Received, Two Years	16,633		16,633
Lease Payments to be Received, Three Years	15,943		15,943
Lease Payments to be Received, Four Years	15,373		15,373
Lease Payments to be Received, Five Years	14,937		14,937
Lease Payments to be Received, Thereafter	236,842		236,842
Total minimum lease payments	304,090		304,090
Other Northwest Holdings [Member]
Operating Leases Payment to be Received [Abstract]
Operating Lease, Payments to be Received, Remainder of Fiscal Year	13		13
Lessor, Operating Lease, Payment to be Received, Year One	51		51
Operating Lease, Payments to be Received, Two Years	52		52
Operating Lease, Payments to be Received, Three Years	53		53
Operating Lease, Payments to be Received, Four Years	56		56
Operating Lease, Payments to be Received, Thereafter	914		914
Total minimum lease payments	1,139		1,139
Total Lease Payments to be Received [Abstract]
Lease Payments to be Received, Remainder of Fiscal Year	13		13
Lease Payments to be Received, Two Years	51		51
Lease Payments to be Received, Three Years	52		52
Lease Payments to be Received, Four Years	53		53
Lease Payments to be Received, Five Years	56		56
Lease Payments to be Received, Thereafter	914		914
Total minimum lease payments	$ 1,139		$ 1,139
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	4,217		4,217
Sales-Type and Direct Financing Leases, Lease Receivable, to be Received, Year One	16,557		16,557
Sales-type Lease, Payments to be Received, Two Years	15,867		15,867
Sales-type Lease, Payments to be Received, Three Years	15,306		15,306
Sales-type Lease, Payments to be Received, Four Years	14,901		14,901
Sales-type Lease, Payments to be Received, Thereafter	236,820		236,820
Total minimum lease payments	303,668		303,668
Less: imputed interest	168,188		168,188
Total leases receivable	135,480		135,480
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	4,217		4,217
Sales-Type and Direct Financing Leases, Lease Receivable, to be Received, Year One	16,557		16,557
Sales-type Lease, Payments to be Received, Two Years	15,867		15,867
Sales-type Lease, Payments to be Received, Three Years	15,306		15,306
Sales-type Lease, Payments to be Received, Four Years	14,901		14,901
Sales-type Lease, Payments to be Received, Thereafter	236,820		236,820
Total minimum lease payments	303,668		303,668
Less: imputed interest	168,188		168,188
Total leases receivable	135,480		135,480
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

Leases - Lease Expense

Leases - Lease Expense - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Lease Expense [Abstract]
Operating Lease, Expense	$ 1,774	$ 1,749	$ 5,257	$ 5,173
Short-term Lease, Cost	$ 105	499	$ 684	1,068
Lessee, Operating Lease, Maximum Term of Short-term Leases not recorded on the Balance Sheet	12 months		12 months
Minimum [Member]
Operating Lease Terms [Abstract]
Lessee, Operating Lease, Term of Contract	2 months		2 months
Maximum [Member]
Operating Lease Terms [Abstract]
Lessee, Operating Lease, Term of Contract	18 years		18 years
Northwest Natural Gas Company [Member]
Lease Expense [Abstract]
Operating Lease, Expense	$ 1,767	1,735	$ 5,235	5,123
Short-term Lease, Cost	105	499	684	1,068
Other Northwest Holdings [Member] | Corporate, Non-Segment [Member]
Lease Expense [Abstract]
Operating Lease, Expense	$ 7	$ 14	$ 22	$ 50

Leases - Lease Asset and Liabil

Leases - Lease Asset and Liabilities - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Operating Lease Asset and Liabilities [Abstract]
Operating lease right of use asset	$ 73,145	$ 75,634	$ 73,145	$ 75,634	$ 75,049
Operating lease liabilities current liabilities	1,361	1,213	1,361	1,213	1,296
Operating lease liabilities noncurrent liabilities	78,469	79,789	78,469	79,789	79,468
Total operating lease liabilities	$ 79,830	$ 81,002	$ 79,830	$ 81,002	$ 80,764
Operating Lease, Weighted Average Remaining Lease Term	17 years 6 months	18 years 4 months 24 days	17 years 6 months	18 years 4 months 24 days	18 years 2 months 12 days
Operating Lease, Weighted Average Discount Rate, Percent	7.30%	7.20%	7.30%	7.20%	7.20%
Commencement of Significant Lease [Abstract]
Lessee, Operating Lease, Liability, Payments, Due	$ 147,055		$ 147,055
Regulatory Assets, Noncurrent	301,660	$ 325,071	301,660	$ 325,071	$ 314,579
Maturity of Operating Lease Liabilities [Abstract]
Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year	1,760		1,760
Lessee, Operating Lease, Liability, to be Paid, Year One	7,072		7,072
Lessee, Operating Lease, Liability, Payments, Due Year Two	7,210		7,210
Lessee, Operating Lease, Liability, Payments, Due Year Three	7,205		7,205
Lessee, Operating Lease, Liability, Payments, Due Year Four	7,359		7,359
Lessee, Operating Lease, Liability, Payments, Due after Year Five	116,449		116,449
Lessee, Operating Lease, Liability, Payments, Due	147,055		147,055
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	67,225		67,225
Total operating lease liabilities	79,830	81,002	79,830	81,002	80,764
Operating lease liabilities current liabilities	1,361	1,213	1,361	1,213	1,296
Operating lease liabilities noncurrent liabilities	78,469	79,789	78,469	79,789	79,468
Finance Lease, Liability, Payments, Due Next Twelve Months	0		0
Leases Cash Flow [Abstract]
Operating cash flows from operating leases	1,771	1,745	5,249	5,164
Finance Lease, Principal Payments	92	123	474	801
nwn:Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	61
Operating leases		0	61	154
Right-of-Use Asset Obtained in Exchange for Finance Lease Liability	6	75	226	169
Finance Leases [Abstract]
Finance Lease, Liability	0		0
Finance Lease, Right-of-Use Asset	2,300	1,900	2,300	1,900	2,100
Other Northwest Holdings [Member] | Corporate, Non-Segment [Member]
Operating Lease Asset and Liabilities [Abstract]
Operating lease right of use asset	99	69	99	69	62
Operating lease liabilities current liabilities	63	29	63	29	23
Operating lease liabilities noncurrent liabilities	33	37	33	37	37
Total operating lease liabilities	96	66	96	66	60
Commencement of Significant Lease [Abstract]
Lessee, Operating Lease, Liability, Payments, Due	105		105
Maturity of Operating Lease Liabilities [Abstract]
Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year	8		8
Lessee, Operating Lease, Liability, to be Paid, Year One	26		26
Lessee, Operating Lease, Liability, Payments, Due Year Two	27		27
Lessee, Operating Lease, Liability, Payments, Due Year Three	20		20
Lessee, Operating Lease, Liability, Payments, Due Year Four	6		6
Lessee, Operating Lease, Liability, Payments, Due after Year Five	18		18
Lessee, Operating Lease, Liability, Payments, Due	105		105
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	9		9
Total operating lease liabilities	96	66	96	66	60
Operating lease liabilities current liabilities	63	29	63	29	23
Operating lease liabilities noncurrent liabilities	33	37	33	37	37
Leases Cash Flow [Abstract]
Operating cash flows from operating leases	12	18	24	51
Operating leases	61	0	61	0
Northwest Natural Gas Company [Member]
Operating Lease Asset and Liabilities [Abstract]
Operating lease right of use asset	73,046	75,565	73,046	75,565	74,987
Operating lease liabilities current liabilities	1,298	1,184	1,298	1,184	1,273
Operating lease liabilities noncurrent liabilities	78,436	79,752	78,436	79,752	79,431
Total operating lease liabilities	79,734	80,936	79,734	80,936	80,704
Commencement of Significant Lease [Abstract]
Lessee, Operating Lease, Liability, Payments, Due	146,950		146,950
Regulatory Assets, Noncurrent	301,596	325,031	301,596	325,031	314,539
Maturity of Operating Lease Liabilities [Abstract]
Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year	1,752		1,752
Lessee, Operating Lease, Liability, to be Paid, Year One	7,046		7,046
Lessee, Operating Lease, Liability, Payments, Due Year Two	7,183		7,183
Lessee, Operating Lease, Liability, Payments, Due Year Three	7,185		7,185
Lessee, Operating Lease, Liability, Payments, Due Year Four	7,353		7,353
Lessee, Operating Lease, Liability, Payments, Due after Year Five	116,431		116,431
Lessee, Operating Lease, Liability, Payments, Due	146,950		146,950
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	67,216		67,216
Total operating lease liabilities	79,734	80,936	79,734	80,936	80,704
Operating lease liabilities current liabilities	1,298	1,184	1,298	1,184	1,273
Operating lease liabilities noncurrent liabilities	78,436	79,752	78,436	79,752	79,431
Leases Cash Flow [Abstract]
Operating cash flows from operating leases	1,759	1,727	5,225	5,113
Finance Lease, Principal Payments	92	123	474	801
nwn:Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	0
Operating leases		0	0	154
Right-of-Use Asset Obtained in Exchange for Finance Lease Liability	$ 6	75	$ 226	169
New Headquarters Lease [Member]
Commencement of Significant Lease [Abstract]
Lessee, Operating Lease, Term of Contract	20 years		20 years
Regulatory Assets, Noncurrent	$ 6,600	$ 5,300	$ 6,600	$ 5,300	$ 5,700
New Headquarters Lease Renewal Term 2 of 2 [Member] | New Headquarters Lease [Member]
Commencement of Significant Lease [Abstract]
Lessee, Operating Lease, Renewal Term	7 years		7 years
New Headquarters Lease Renewal Term 1 of 2 [Member] | New Headquarters Lease [Member]
Commencement of Significant Lease [Abstract]
Lessee, Operating Lease, Renewal Term	7 years		7 years
Maximum [Member]
Commencement of Significant Lease [Abstract]
Lessee, Operating Lease, Term of Contract	18 years		18 years

Stock-Based Compensation_2

Stock-Based Compensation - Long Term Incentive Plan $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2022 USD ($) $ / shares shares
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted (in shares)	31,830
Award vesting period	3 years
Unrecognized compensation costs | $	$ 100
Performance Shares | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Conversion ratio, percent of target	0%
Performance Shares | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Conversion ratio, percent of target	200%
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	4 years
Number of RSUs granted in period (in shares)	46,812
Weighted-average grant date fair value (in dollars per share) | $ / shares	$ 46.60
Unrecognized compensation costs | $	$ 3,800
A 2021 and 2022 Award | Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Payment Arrangement, Expense | $	$ 0
Target Achieved [Member] | A 2021 Award | Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share Based Compensation Award Target Share	55,250
Target Achieved [Member] | A 2022 Award | Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share Based Compensation Award Target Share	55,870

Debt Short-term Debt

Debt Short-term Debt - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Dec. 31, 2021	Sep. 30, 2021
Short-term Debt [Line Items]
Short-term debt	$ 141,000	$ 389,500	$ 399,500
Commercial Paper Maximum Maturity	18 days
Commercial Paper Average Maturity	9 days
Northwest Natural Gas Company [Member]
Short-term Debt [Line Items]
Short-term debt	$ 53,000	$ 245,500	$ 370,500
Line of Credit [Member]
Short-term Debt [Line Items]
Short-term debt	$ 88,000
Debt, Weighted Average Interest Rate	4.70%
Commercial Paper [Member] | Northwest Natural Gas Company [Member]
Short-term Debt [Line Items]
Short-term debt	$ 53,000
Debt, Weighted Average Interest Rate	3.30%

Long-Term Debt

Long-Term Debt - USD ($)	9 Months Ended
	Sep. 30, 2022	Dec. 31, 2021	Sep. 30, 2021
Debt Instrument [Line Items]
Long-term Debt	$ 1,337,620,000	$ 1,044,932,000	$ 916,304,000
Unamortized debt issuance costs	$ 8,348,000	8,309,000	7,051,000
Ratio of Indebtedness to Net Capital	0.569
Northwest Natural Gas Company [Member]
Debt Instrument [Line Items]
Long-term Debt	$ 1,126,471,000	986,495,000	857,760,000
Unamortized debt issuance costs	$ 8,229,000	$ 8,205,000	$ 6,940,000
Weighted average interest rate	4.50%
Long-Term Debt, Maturity, Year One	$ 50,000,000
Northwest Natural Gas Company [Member] | Minimum [Member]
Debt Instrument [Line Items]
Stated interest rate	2.80%
Northwest Natural Gas Company [Member] | Maximum [Member]
Debt Instrument [Line Items]
Stated interest rate	7.90%
Five-year Term Loan Due 2026
Debt Instrument [Line Items]
Stated interest rate	3.50%
Long-term Debt, Term	5 years
Proceeds from Issuance of Debt	$ 55,000,000
Debt Instrument Covenant Consolidated Indebtedness to Capitalization Ratio	70%
18 Month Credit Agreement Due March 15, 2024
Debt Instrument [Line Items]
Stated interest rate	4.10%
Long-term Debt, Term	18 months
Proceeds from Issuance of Debt	$ 100,000,000
Debt Instrument Covenant Consolidated Indebtedness to Capitalization Ratio	70%
18 Month Credit Agreement Due March 15, 2024 | NWN Water
Debt Instrument [Line Items]
Stated interest rate	4.10%
Long-term Debt, Term	18 months
Proceeds from Issuance of Debt	$ 50,000,000
Debt Instrument Covenant Consolidated Indebtedness to Capitalization Ratio	70%
First Mortgage Bonds 4.8 Percent Series Due 2052 | Northwest Natural Gas Company [Member]
Debt Instrument [Line Items]
Stated interest rate	4.80%
Proceeds from Issuance of Debt	$ 140,000,000
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed	100%

Debt Fair Value of Long Term De

Debt Fair Value of Long Term Debt - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021	Sep. 30, 2021
Debt Instrument [Line Items]
Gross long-term debt	$ 1,345,968	$ 1,053,241	$ 923,355
Unamortized debt issuance costs	(8,348)	(8,309)	(7,051)
Carrying amount	1,337,620	1,044,932	916,304
Estimated fair value	1,133,087	1,174,500	1,042,705
Northwest Natural Gas Company [Member]
Debt Instrument [Line Items]
Gross long-term debt	1,134,700	994,700	864,700
Unamortized debt issuance costs	(8,229)	(8,205)	(6,940)
Carrying amount	1,126,471	986,495	857,760
Estimated fair value	$ 927,372	$ 1,110,741	$ 978,613

Pension and Other Postretirem_3

Pension and Other Postretirement Benefit Costs - Net Periodic Benefit Cost - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 1,022	$ 1,717	$ 4,450	$ 5,145
Interest cost	4,260	3,316	10,945	10,001
Expected return on plan assets	(7,076)	(5,802)	(19,274)	(18,000)
Amortization of net actuarial loss	0	0	0	0
Defined Benefit Plan, Amortization of Gain (Loss)	(1,542)	5,515	9,459	16,516
Net periodic benefit cost	(3,336)	4,746	5,580	13,662
Amount allocated to construction	(496)	(759)	(1,965)	(2,228)
Defined Benefit Plan Net Periodic Benefit Cost Charged To Expense	(3,832)	3,987	3,615	11,434
Amortization of Regulatory Balancing Account	675	675	4,757	4,757
Net amount charged to expense	(3,157)	4,662	8,372	16,191
Other Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	34	69	145	180
Interest cost	213	180	543	510
Expected return on plan assets	0	0	0	0
Amortization of net actuarial loss	(15)	(119)	(249)	(353)
Defined Benefit Plan, Amortization of Gain (Loss)	57	226	319	488
Net periodic benefit cost	289	356	758	825
Amount allocated to construction	(14)	(27)	(57)	(70)
Defined Benefit Plan Net Periodic Benefit Cost Charged To Expense	275	329	701	755
Amortization of Regulatory Balancing Account	0	0	0	0
Net amount charged to expense	$ 275	$ 329	$ 701	$ 755

Pension and Other Postretirem_4

Pension and Other Postretirement Benefit Costs - Amounts Recognized in Accumulated Other Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract]
Beginning balance	$ (11,010)	$ (12,460)	$ (11,404)	$ (12,902)
Amortization of actuarial losses	275	314	811	916
Total reclassifications before tax	275	314	811	916
Tax benefit	(73)	(80)	(215)	(240)
Total reclassifications for the period	202	234	596	676
Ending balance	$ (10,808)	$ (12,226)	$ (10,808)	$ (12,226)

Pension and Other Postretirem_5

Pension and Other Postretirement Benefit Costs - Narrative - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Pension and Other Postretirement Benefits Cost (Reversal of Cost) [Abstract]
Defined benefit pension plan cash contributions	$ 0	$ (9,600)
Estimated future employer contributions in next fiscal year	0
Employer contributions	$ 7,400	$ 6,700

Income Tax_2_3

Income Tax - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Income taxes at statutory rates (federal and state)	$ (5,533)	$ (5,834)	$ 10,710	$ 10,764
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount	(2,376)	(2,599)	4,298	4,660
Differences required to be flowed-through by regulatory commissions	1,232	1,318	(2,003)	(2,266)
Other, net	(81)	(12)	(370)	(41)
Total provision for income taxes on continuing operations	$ (6,758)	$ (7,127)	$ 12,635	$ 13,117
Effective tax rate for continuing operations	25.70%	25.70%	24.80%	25.60%
Northwest Natural Gas Company [Member]
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Income taxes at statutory rates (federal and state)	$ (5,305)	$ (5,928)	$ 11,554	$ 11,195
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount	(2,306)	(2,618)	4,497	4,748
Differences required to be flowed-through by regulatory commissions	1,232	1,318	(2,003)	(2,266)
Other, net	(76)	16	(370)	(49)
Total provision for income taxes on continuing operations	$ (6,455)	$ (7,212)	$ 13,678	$ 13,628
Effective tax rate for continuing operations	25.60%	25.50%	24.90%	25.60%

Property, Plant and Equipment_3

Property, Plant and Equipment - USD ($)	Sep. 30, 2022	Dec. 31, 2021	Sep. 30, 2021
Property, Plant and Equipment [Line Items]
Property, plant, and equipment	$ 4,207,328,000	$ 3,997,243,000	$ 3,919,096,000
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	1,166,150,000	1,125,873,000	1,112,734,000
Total property, plant, and equipment, net	3,041,178,000	2,871,370,000	2,806,362,000
Natural Gas Distribution [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment	3,888,092,000	3,721,939,000	3,663,699,000
Public Utilities, Property, Plant and Equipment, Construction Work in Progress	161,658,000	135,398,000	120,412,000
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	1,135,965,000	1,098,715,000	1,086,510,000
Total property, plant, and equipment, net	2,913,785,000	2,758,622,000	2,697,601,000
Other Northwest Natural [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment	69,626,000	69,332,000	66,314,000
Public Utilities, Property, Plant and Equipment, Construction Work in Progress	5,112,000	4,971,000	7,228,000
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	21,435,000	20,646,000	20,392,000
Total property, plant, and equipment, net	53,303,000	53,657,000	53,150,000
Northwest Natural Gas Company [Member]
Property, Plant and Equipment [Line Items]
Total property, plant, and equipment, net	2,967,088,000	2,812,279,000	2,750,751,000
Property, Plant, Equipment non-cash	43,954,000	37,537,000	33,968,000
Other Northwest Holdings [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment	66,208,000	57,184,000	53,175,000
Public Utilities, Property, Plant and Equipment, Construction Work in Progress	16,632,000	8,419,000	8,268,000
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	8,750,000	6,512,000	5,832,000
Total property, plant, and equipment, net	74,090,000	59,091,000	55,611,000
Northwest Holdings [Member]
Property, Plant and Equipment [Line Items]
Property, Plant, Equipment non-cash	45,374,000	38,333,000	35,955,000
Northwest Natural Gas Company [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment	4,124,488,000	3,931,640,000	3,857,652,000
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	1,157,400,000	1,119,361,000	1,106,901,000
Total property, plant, and equipment, net	$ 2,967,088,000	$ 2,812,279,000	$ 2,750,751,000

Investments_2_3

Investments $ in Thousands	3 Months Ended
	Sep. 30, 2022 USD ($) employee numberOfProjects numberOfConnections	Jul. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Sep. 30, 2021 USD ($)
Schedule of Equity Method Investments [Line Items]
Life Insurance, Corporate or Bank Owned, Amount	$ 49,043		$ 48,178	$ 47,970
Gas reserves, noncurrent	23,770		26,608	28,021
Equity Method Investment, Aggregate Cost	23,756		14,492	36
Other investments	96,569		89,278	76,027
Total cumulative gas reserves investment	188,000
Deferred Taxes Related To Gas Reserves	5,500		6,900	7,800
Gas reserves, current	$ 3,700		5,400	6,300
Investments, Number of RNG Development Projects | numberOfProjects	4
Northwest Natural Gas Company [Member]
Schedule of Equity Method Investments [Line Items]
Life Insurance, Corporate or Bank Owned, Amount	$ 49,043		48,178	47,970
Gas reserves, noncurrent	23,770		26,608	28,021
Equity Method Investment, Aggregate Cost	8,058		0	0
Other investments	80,871		$ 74,786	$ 75,991
Lexington | Northwest Natural Gas Company [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Aggregate Cost	8,100
Deconsolidation, Gain (Loss), Amount	$ 0
Other Northwest Holdings [Member] | Avion Water
Schedule of Equity Method Investments [Line Items]
Ownership percentage of Avion	40.30%		37.30%
Investment balance in Avion			$ 14,500
Equity Method Investment, Number of Customer Connections | numberOfConnections	15,000
Equity Method Investment, Number of Employees | employee	35
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity	$ 10,600
Equity Method Investment, Additional Underlying Equity in Net Assets		$ 1,000

Business Combinations Busines_2

Business Combinations Business Combinations	9 Months Ended	12 Months Ended
	Sep. 30, 2022 USD ($) numberOfConnections	Dec. 31, 2021 USD ($)	Sep. 30, 2021 USD ($)
Business Acquisition [Line Items]
Goodwill	$ 74,732,000	$ 70,570,000	$ 69,789,000
Goodwill, Impairment Loss	0
Business Combination, Consideration Transferred	$ 4,200,000
Other insignificant acquisitions [Member]
Business Acquisition [Line Items]
Number of Businesses Acquired	3	4

Derivative Instruments Notional

Derivative Instruments Notional Amounts - Northwest Natural Gas Company [Member] therm in Thousands, $ in Thousands	Sep. 30, 2022 USD ($) therm	Dec. 31, 2021 USD ($) therm	Sep. 30, 2021 USD ($) therm
Gas Year 2021-2022
Derivative [Line Items]
TargetHedgeAchieved	80%
Gas Year 2021-2022 | Oregon [Member]
Derivative [Line Items]
TargetHedgeAchieved	80%
Gas Year 2021-2022 | WASHINGTON
Derivative [Line Items]
TargetHedgeAchieved	79%
Financial [Member] | Gas Year 2021-2022 | Oregon [Member]
Derivative [Line Items]
TargetHedgeAchieved	63%
Financial [Member] | Gas Year 2021-2022 | WASHINGTON
Derivative [Line Items]
TargetHedgeAchieved	66%
Physical [Member] | Gas Year 2021-2022 | Oregon [Member]
Derivative [Line Items]
TargetHedgeAchieved	17%
Physical [Member] | Gas Year 2021-2022 | WASHINGTON
Derivative [Line Items]
TargetHedgeAchieved	13%
Natural Gas Therms [Member] | Financial [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	1,006,665	618,815	749,595
Natural Gas Therms [Member] | Physical [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	672,350	431,628	613,524
Foreign Exchange Contract [Member]
Derivative [Line Items]
Derivative, Notional Amount | $	$ 9,905	$ 6,268	$ 6,299

Unrealized and Realized Gain_Lo

Unrealized and Realized Gain/Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Derivative [Line Items]
Derivative, Gain on Derivative	$ 16,900	$ 6,100	$ 74,000	$ 15,400
Financial [Member]
Derivative [Line Items]
Incremental Cost or Benefit to Collect or Refund to Customers			0
Northwest Holdings and Northwest Natural [Member] | Natural gas commodity
Derivative [Line Items]
Gain (Loss) on Derivative Instruments, Net, Pretax	0	0	0	(4)
Northwest Holdings and Northwest Natural [Member] | Foreign exchange
Derivative [Line Items]
Gain (Loss) on Derivative Instruments, Net, Pretax	0	0	0	0
Northwest Holdings and Northwest Natural [Member] | Benefit (expense) to cost of gas | Natural gas commodity
Derivative [Line Items]
Gain (Loss) on Derivative Instruments, Net, Pretax	(11,626)	69,239	32,827	(106,044)
Northwest Holdings and Northwest Natural [Member] | Benefit (expense) to cost of gas | Foreign exchange
Derivative [Line Items]
Gain (Loss) on Derivative Instruments, Net, Pretax	(455)	(106)	(528)	(74)
Northwest Holdings and Northwest Natural [Member] | Sales [Member] | Natural gas commodity
Derivative [Line Items]
Gain (Loss) on Derivative Instruments, Net, Pretax	0	0	0	(26)
Northwest Holdings and Northwest Natural [Member] | Sales [Member] | Foreign exchange
Derivative [Line Items]
Gain (Loss) on Derivative Instruments, Net, Pretax	0	0	0	0
Deferred Derivative Gain (Loss) [Member] | Northwest Holdings and Northwest Natural [Member] | Natural gas commodity
Derivative [Line Items]
Gain (Loss) on Derivative Instruments, Net, Pretax	11,626	(69,239)	(32,827)	(106,022)
Deferred Derivative Gain (Loss) [Member] | Northwest Holdings and Northwest Natural [Member] | Foreign exchange
Derivative [Line Items]
Gain (Loss) on Derivative Instruments, Net, Pretax	$ 455	$ 106	$ 528	$ 74

Derivative Instruments Credit R

Derivative Instruments Credit Rating - USD ($)	3 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Collateral Posted with NW Natural Counterparties [Member]
Derivative [Line Items]
Additional Collateral, Aggregate Fair Value	$ 0	$ 0
Northwest Natural Gas Company [Member]
Derivative [Line Items]
Unrealized Gain (Loss) on Derivatives	35,100,000	132,200,000
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	40,800,000	124,500,000	$ 51,800,000
Derivative liability	$ 8,500,000	$ 4,900,000	$ 3,800,000

Derivative Instruments Fair Val

Derivative Instruments Fair Value - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021	Sep. 30, 2021
Derivative [Line Items]
Derivative, Fair Value, Net	$ 32.3	$ 48	$ 119.6

Environmental Matters_2_3

Environmental Matters	Sep. 30, 2022
Oregon [Member]
Site Contingency [Line Items]
Remediation Recovery Percentage	96.70%
WASHINGTON
Site Contingency [Line Items]
Remediation Recovery Percentage	3.30%

Environmental Matters - Environ

Environmental Matters - Environmental Sites $ in Thousands	1 Months Ended	9 Months Ended
	Jan. 31, 2017 USD ($)	Sep. 30, 2022 USD ($) party property	Dec. 31, 2021 USD ($)	Sep. 30, 2021 USD ($)
Site Contingency [Line Items]
Current Liabilities		$ 16,554	$ 26,985	$ 20,039
Non-Current Liabilities		83,276	88,851	85,631
Gasco/Siltronic Sediments
Site Contingency [Line Items]
Current Liabilities		5,556	7,582	6,925
Non-Current Liabilities		40,740	42,076	40,929
Site Contingency, Environmental Remediation Costs Recognized		46,300
Gasco/Siltronic Sediments | Minimum [Member]
Site Contingency [Line Items]
Environmental Exit Costs, Anticipated Cost		46,300
Gasco/Siltronic Sediments | Maximum [Member]
Site Contingency [Line Items]
Environmental Exit Costs, Anticipated Cost		350,000
Portland Harbor Other [Member]
Site Contingency [Line Items]
Current Liabilities		2,430	2,592	2,392
Non-Current Liabilities		$ 8,135	9,570	6,222
Gasco Uplands [Member]
Site Contingency [Line Items]
Site contingency: number of management pieces		2
Gasco/Siltronic Upland [Member]
Site Contingency [Line Items]
Current Liabilities		$ 8,367	15,711	9,720
Non-Current Liabilities		33,354	36,215	37,408
Front Street [Member]
Site Contingency [Line Items]
Current Liabilities		201	1,100	1,002
Non-Current Liabilities		868	811	893
Additional studies and design costs		1,100
Oregon Steel Mills [Member]
Site Contingency [Line Items]
Current Liabilities		0	0	0
Non-Current Liabilities		$ 179	$ 179	$ 179
Portland Harbor [Member]
Site Contingency [Line Items]
Number of potentially responsible parties (more than) | party		100
EPA final feasibility study and proposed remediation plan, clean-up costs, portland harbor	$ 1,050,000
Number of remediation projects | property		2
Portland Harbor [Member] | Minimum [Member]
Site Contingency [Line Items]
Percentage of clean-up costs	(30.00%)
Portland Harbor [Member] | Maximum [Member]
Site Contingency [Line Items]
Percentage of clean-up costs	50%
Yakama Nation [Member] | Portland Harbor Other [Member]
Site Contingency [Line Items]
Trustee Council Members - Number of Claimants		1
Site Contingency, Number of Other Third-Party Defendants		29
NRD liability claim yakama nation		$ 300
Number of Amended Complaints Filed		2

Environmental Matters - Regulat

Environmental Matters - Regulatory Deferred Assets - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Dec. 31, 2021	Sep. 30, 2021
Site Contingency [Line Items]
Regulatory Assets, Current	$ 104,830	$ 72,391	$ 80,638
Regulatory Assets, Noncurrent	$ 301,660	$ 314,579	$ 325,071
Remediation Non-recovery Percentage	3.30%	3.30%	3.30%
Annual tariff rider collection	$ 5,000
Annual insurance proceeds to apply against remediation costs	5,000
Total annual remediation expense and interest	$ 10,000
Oregon [Member]
Site Contingency [Line Items]
Remediation Recovery Percentage	96.70%
Front Street [Member] | Environmental costs [Member]
Site Contingency [Line Items]
Accrued site liabilities	$ 34	$ 62	$ 62
Northwest Natural Gas Company [Member]
Site Contingency [Line Items]
Regulatory Assets, Current	104,830	72,391	80,638
Regulatory Assets, Noncurrent	301,596	314,539	325,031
Northwest Natural Gas Company [Member] | Environmental costs [Member]
Site Contingency [Line Items]
Deferred costs and interest	47,011	45,122	45,019
Accrued site liabilities	99,795	115,773	105,607
Insurance proceeds and interest	(54,678)	(59,564)	(59,589)
Regulatory Assets	92,128	101,331	91,037
Regulatory Assets, Current	9,461	6,694	7,068
Regulatory Assets, Noncurrent	$ 82,667	$ 94,636	$ 83,969

Subsequent Events_2

Subsequent Events - USD ($)	3 Months Ended	9 Months Ended
	Dec. 31, 2022	Sep. 30, 2022
Subsequent Event [Line Items]
Business Combination, Consideration Transferred		$ 4,200,000
Subsequent Event [Member] | NWN Water | Far West Water & Sewer Inc.
Subsequent Event [Line Items]
Business Combination, Consideration Transferred	$ 88,000,000
Business Acquisition, Connections of Acquired Business	25,000
Business Acquisition, Employees of Acquired Business	40