Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022
Current assets:
Cash and cash equivalents	$ 140,821	$ 29,270	$ 24,325
Accounts receivable	164,157	168,906	103,131
Accrued unbilled revenue	59,542	89,048	41,772
Allowance for uncollectible accounts	(6,760)	(3,296)	(2,488)
Regulatory assets	126,546	117,491	64,481
Derivative instruments	8,507	194,412	84,438
Inventories	41,392	87,096	33,377
Other current assets	41,968	61,286	42,329
Total current assets	576,173	744,213	391,365
Non-current assets:
Property, plant, and equipment	4,320,476	4,261,566	4,041,894
Less: Accumulated depreciation	1,164,498	1,147,166	1,137,138
Total property, plant, and equipment, net	3,155,978	3,114,400	2,904,756
Regulatory assets	311,419	340,432	297,546
Derivative instruments	1,432	5,045	6,955
Other investments	93,611	95,704	96,266
Operating lease right of use asset, net	72,699	73,429	74,416
Assets under sales-type leases	133,159	134,302	137,837
Goodwill	149,836	149,283	70,570
Other non-current assets	97,789	91,518	74,923
Total non-current assets	4,015,923	4,004,113	3,663,269
Total assets	4,592,096	4,748,326	4,054,634
Current liabilities:
Short-term debt	72,500	258,200	332,500
Current maturities of long-term debt	240,712	90,697	339
Accounts payable	111,152	180,667	130,557
Taxes accrued	31,372	15,625	14,258
Interest accrued	13,089	10,169	10,886
Regulatory liabilities	57,523	248,582	111,791
Derivative instruments	44,370	28,728	3,855
Operating lease liabilities	1,700	1,514	1,303
Other current liabilities	71,662	64,552	52,778
Total current liabilities	644,080	898,734	658,267
Long-term debt	1,294,590	1,246,167	1,044,667
Deferred credits and other non-current liabilities:
Deferred tax liabilities	376,237	366,022	353,746
Regulatory liabilities	669,328	689,578	652,977
Pension and other postretirement benefit liabilities	147,890	149,143	164,530
Derivative instruments	15,382	20,838	592
Operating lease liabilities	78,302	78,965	79,162
Other non-current liabilities	117,980	123,438	112,749
Total deferred credits and other non-current liabilities	1,405,119	1,427,984	1,363,756
Commitments and contingencies (Note 16)
Equity:
Common stock	$ 824,304	$ 805,253	$ 602,382
Shares Authorized (in shares)	100,000,000	100,000,000	100,000,000
Shares outstanding (in shares)	35,929,000	35,525,000	31,380,000
Shares issued (in shares)	35,929,000	35,525,000	31,380,000
Par Value (in dollars per share)	$ 0	$ 0	$ 0
Retained earnings	$ 430,597	$ 376,473	$ 396,769
Accumulated other comprehensive loss	(6,594)	(6,285)	(11,207)
Total equity	1,248,307	1,175,441	987,944
Total liabilities and equity	4,592,096	4,748,326	4,054,634
Northwest Natural Gas Company [Member]
Current assets:
Cash and cash equivalents	129,731	12,977	10,165
Accounts receivable	158,675	165,607	101,551
Accrued unbilled revenue	57,855	87,482	41,651
Receivables from affiliates	2,388	634	1,850
Allowance for uncollectible accounts	(3,937)	(3,079)	(2,432)
Regulatory assets	126,546	117,491	64,481
Derivative instruments	8,890	194,236	84,438
Inventories	39,835	86,207	32,757
Other current assets	40,950	57,269	39,507
Total current assets	560,933	718,824	373,968
Non-current assets:
Property, plant, and equipment	4,200,299	4,148,547	3,971,050
Less: Accumulated depreciation	1,153,060	1,137,231	1,129,837
Total property, plant, and equipment, net	3,047,239	3,011,316	2,841,213
Regulatory assets	311,394	340,407	297,482
Derivative instruments	1,432	5,045	6,955
Other investments	78,102	80,110	81,797
Operating lease right of use asset, net	72,077	72,720	74,361
Assets under sales-type leases	133,158	134,302	137,837
Other non-current assets	96,300	89,994	73,207
Total non-current assets	3,739,702	3,733,894	3,512,852
Total assets	4,300,635	4,452,718	3,886,820
Current liabilities:
Short-term debt	0	170,200	188,500
Current maturities of long-term debt	89,962	89,942	0
Accounts payable	107,986	177,590	127,569
Payables to affiliates	24,806	9,175	9,619
Taxes accrued	15,120	15,426	14,224
Interest accrued	12,535	8,900	10,708
Regulatory liabilities	57,494	248,553	111,791
Derivative instruments	44,370	28,728	3,855
Operating lease liabilities	1,538	1,363	1,286
Other current liabilities	69,114	62,019	52,053
Total current liabilities	422,925	811,896	519,605
Long-term debt	1,234,460	1,035,935	986,627
Deferred credits and other non-current liabilities:
Deferred tax liabilities	374,092	362,353	351,191
Regulatory liabilities	668,348	688,599	651,995
Pension and other postretirement benefit liabilities	147,890	149,143	164,530
Derivative instruments	15,382	20,838	592
Operating lease liabilities	77,840	78,345	79,125
Other non-current liabilities	109,518	114,527	111,546
Total deferred credits and other non-current liabilities	1,393,070	1,413,805	1,358,979
Commitments and contingencies (Note 16)
Equity:
Common stock	614,911	614,903	436,042
Retained earnings	641,581	582,593	596,774
Accumulated other comprehensive loss	(6,312)	(6,414)	(11,207)
Total equity	1,250,180	1,191,082	1,021,609
Total liabilities and equity	$ 4,300,635	$ 4,452,718	$ 3,886,820