Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021
Current assets:
Cash and cash equivalents	$ 24,325	$ 18,559	$ 17,907
Accounts receivable	103,131	101,495	105,226
Accrued unbilled revenue	41,772	82,169	41,907
Allowance for uncollectible accounts	(2,488)	(2,018)	(3,503)
Regulatory assets	64,481	72,391	47,789
Derivative instruments	84,438	48,130	19,914
Inventories	33,377	57,262	26,237
Income taxes receivable	0	0	6,000
Other current assets	42,329	59,288	41,315
Total current assets	391,365	437,276	302,792
Non-current assets:
Property, plant, and equipment	4,041,894	3,997,243	3,788,283
Less: Accumulated depreciation	1,137,138	1,125,873	1,091,903
Total property, plant, and equipment, net	2,904,756	2,871,370	2,696,380
Regulatory assets	297,546	314,579	338,692
Derivative instruments	6,955	10,730	3,087
Other investments	96,266	89,278	79,034
Operating lease right of use asset, net	74,416	75,049	76,957
Assets under sales-type leases	137,837	138,995	142,586
Goodwill	70,570	70,570	69,330
Other non-current assets	74,923	56,757	49,767
Total non-current assets	3,663,269	3,627,328	3,455,833
Total assets	4,054,634	4,064,604	3,758,625
Current liabilities:
Short-term debt	332,500	389,500	236,225
Current maturities of long-term debt	339	345	95,265
Accounts payable	130,557	133,486	88,591
Taxes accrued	14,258	15,520	23,550
Interest accrued	10,886	7,503	9,491
Regulatory liabilities	111,791	112,281	81,314
Derivative instruments	3,855	10,402	1,038
Operating lease liabilities	1,303	1,296	1,213
Other current liabilities	52,778	54,432	48,978
Total current liabilities	658,267	724,765	585,665
Long-term debt	1,044,667	1,044,587	860,654
Deferred credits and other non-current liabilities:
Deferred tax liabilities	353,746	340,231	328,112
Regulatory liabilities	652,977	658,332	636,384
Pension and other postretirement benefit liabilities	164,530	166,684	210,811
Derivative instruments	592	412	1,272
Operating lease liabilities	79,162	79,468	80,414
Other non-current liabilities	112,749	114,979	118,989
Total deferred credits and other non-current liabilities	1,363,756	1,360,106	1,375,982
Commitments and contingencies (Note 16)
Equity:
Common stock	$ 602,382	$ 590,771	$ 568,066
Shares Authorized (in shares)	100,000,000	100,000,000	100,000,000
Shares outstanding (in shares)	31,380,000	31,129,000	30,655,000
Shares issued (in shares)	31,380,000	31,129,000	30,655,000
Par Value (in dollars per share)	$ 0	$ 0	$ 0
Retained earnings	$ 396,769	$ 355,779	$ 380,939
Accumulated other comprehensive loss	(11,207)	(11,404)	(12,681)
Total equity	987,944	935,146	936,324
Total liabilities and equity	4,054,634	4,064,604	3,758,625
Northwest Natural Gas Company [Member]
Current assets:
Cash and cash equivalents	10,165	12,271	10,418
Accounts receivable	101,551	99,780	96,878
Accrued unbilled revenue	41,651	82,028	41,817
Receivables from affiliates	1,850	261	1,669
Allowance for uncollectible accounts	(2,432)	(1,962)	(3,460)
Regulatory assets	64,481	72,391	47,789
Derivative instruments	84,438	48,130	19,914
Inventories	32,757	56,752	25,737
Other current assets	39,507	47,378	40,745
Total current assets	373,968	417,029	281,507
Non-current assets:
Property, plant, and equipment	3,971,050	3,931,640	3,736,431
Less: Accumulated depreciation	1,129,837	1,119,361	1,087,391
Total property, plant, and equipment, net	2,841,213	2,812,279	2,649,040
Regulatory assets	297,482	314,539	338,652
Derivative instruments	6,955	10,730	3,087
Other investments	81,797	74,786	79,011
Operating lease right of use asset, net	74,361	74,987	76,857
Assets under sales-type leases	137,837	138,995	142,586
Other non-current assets	73,207	55,027	48,828
Total non-current assets	3,512,852	3,481,343	3,338,061
Total assets	3,886,820	3,898,372	3,619,568
Current liabilities:
Short-term debt	188,500	245,500	175,225
Current maturities of long-term debt	0	0	59,971
Accounts payable	127,569	131,475	87,823
Payables to affiliates	9,619	1,248	29,744
Taxes accrued	14,224	15,476	13,865
Interest accrued	10,708	7,296	9,460
Regulatory liabilities	111,791	112,281	81,314
Derivative instruments	3,855	10,402	1,038
Operating lease liabilities	1,286	1,273	1,167
Other current liabilities	52,053	53,591	48,488
Total current liabilities	519,605	578,542	508,095
Long-term debt	986,627	986,495	857,365
Deferred credits and other non-current liabilities:
Deferred tax liabilities	351,191	337,717	326,301
Regulatory liabilities	651,995	657,350	635,515
Pension and other postretirement benefit liabilities	164,530	166,684	210,811
Derivative instruments	592	412	1,272
Operating lease liabilities	79,125	79,431	80,358
Other non-current liabilities	111,546	113,934	118,286
Total deferred credits and other non-current liabilities	1,358,979	1,355,528	1,372,543
Commitments and contingencies (Note 16)
Equity:
Common stock	436,042	435,515	319,506
Retained earnings	596,774	553,696	574,740
Accumulated other comprehensive loss	(11,207)	(11,404)	(12,681)
Total equity	1,021,609	977,807	881,565
Total liabilities and equity	$ 3,886,820	$ 3,898,372	$ 3,619,568