Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019
Current assets:
Cash and cash equivalents	$ 35,926	$ 9,648	$ 10,522
Accounts receivable	40,278	67,137	29,617
Accrued unbilled revenue	14,787	56,192	17,934
Allowance for uncollectible accounts	(1,786)	(673)	(180)
Regulatory assets	29,740	41,929	47,996
Derivative instruments	24,094	6,802	5,987
Inventories	45,082	43,985	41,230
Gas reserves	12,265	15,278	16,392
Income Taxes Receivable, Current	0	256	0
Other current assets	25,534	38,004	18,617
Discontinued operations current assets	16,928	15,134	14,612
Total current assets	242,848	293,692	202,727
Non-current assets:
Property, plant, and equipment	3,680,872	3,476,746	3,416,718
Less: Accumulated depreciation	1,073,623	1,037,847	1,027,330
Property, Plant and Equipment, Net	2,607,249	2,438,899	2,389,388
Gas reserves	37,696	48,394	51,978
Regulatory assets	324,176	343,146	313,890
Derivative instruments	12,921	3,337	1,610
Other investments	48,963	63,333	63,018
Operating lease right of use asset	78,036	2,950	3,917
Assets under sales-type leases	144,971	146,310	147,918
Goodwill	70,292	49,929	49,333
Other non-current assets	50,945	38,464	27,839
Total non-current assets	3,375,249	3,134,762	3,048,891
Total assets	3,618,097	3,428,454	3,251,618
Current liabilities:
Short-term debt	223,000	149,100	65,580
Current maturities of long-term debt	95,173	75,109	94,671
Accounts payable	83,813	113,370	76,197
Taxes accrued	13,772	11,971	13,382
Interest accrued	9,645	7,451	10,406
Regulatory liabilities	59,236	44,657	37,573
Derivative instruments	1,784	2,000	4,156
Operating lease liabilities	1,081	2,101	3,171
Other current liabilities	49,870	62,705	39,873
Discontinued operations current liabilities	13,922	13,709	13,399
Total current liabilities	551,296	482,173	358,408
Long-term debt	860,235	805,955	806,014
Deferred credits and other non-current liabilities:
Deferred tax liabilities	296,516	295,643	284,625
Regulatory liabilities	649,521	625,717	615,813
Pension and other postretirement benefit liabilities	202,938	228,129	215,007
Derivative instruments	921	609	2,998
Operating lease liabilities	80,854	841	732
Other non-current liabilities	123,041	123,388	123,352
Total deferred credits and other non-current liabilities	1,353,791	1,274,327	1,242,527
Commitments and contingencies (Note 16)
Equity:
Common stock	$ 563,852	$ 558,282	$ 556,623
Shares Authorized (in shares)	100,000,000	100,000,000	100,000,000
Shares outstanding (in shares)	30,565,000	30,472,000	30,435,000
Shares issued (in shares)	30,565,000	30,472,000	30,435,000
Par Value (in dollars per share)	$ 0	$ 0	$ 0
Retained earnings	$ 299,150	$ 318,450	$ 296,256
Accumulated other comprehensive loss	(10,227)	(10,733)	(8,210)
Total equity	852,775	865,999	844,669
Total liabilities and equity	3,618,097	3,428,454	3,251,618
Northwest Natural Gas Company [Member]
Current assets:
Cash and cash equivalents	27,133	5,919	6,274
Accounts receivable	31,659	66,823	29,065
Accrued unbilled revenue	14,709	56,139	17,843
Receivables from affiliates	641	787	1,106
Allowance for uncollectible accounts	(1,784)	(672)	(178)
Regulatory assets	29,740	41,929	47,996
Derivative instruments	24,094	6,802	5,987
Inventories	44,709	43,896	41,148
Gas reserves	12,265	15,278	16,392
Other current assets	20,236	33,258	17,519
Total current assets	203,402	270,159	183,152
Non-current assets:
Property, plant, and equipment	3,633,570	3,456,075	3,397,053
Less: Accumulated depreciation	1,070,405	1,036,593	1,026,631
Property, Plant and Equipment, Net	2,563,165	2,419,482	2,370,422
Gas reserves	37,696	48,394	51,978
Regulatory assets	324,136	343,146	313,890
Derivative instruments	12,921	3,337	1,610
Other investments	48,929	49,837	49,503
Operating lease right of use asset	77,949	2,760	3,745
Assets under sales-type leases	144,972	146,310	147,918
Other non-current assets	50,197	38,062	27,423
Total non-current assets	3,259,965	3,051,328	2,966,489
Total assets	3,463,367	3,321,487	3,149,641
Current liabilities:
Short-term debt	150,000	125,100	45,500
Current maturities of long-term debt	59,940	74,907	94,633
Accounts payable	82,582	111,641	75,126
Payables to affiliates	11,134	1,546	4,185
Taxes accrued	13,604	11,717	12,941
Interest accrued	9,552	7,441	10,405
Regulatory liabilities	59,236	44,657	37,573
Derivative instruments	1,784	2,000	4,156
Operating lease liabilities	1,020	1,979	3,075
Other current liabilities	48,555	61,438	38,328
Total current liabilities	437,407	442,426	325,922
Long-term debt	857,174	769,081	768,995
Deferred credits and other non-current liabilities:
Deferred tax liabilities	307,257	309,297	298,039
Regulatory liabilities	648,651	625,717	615,813
Pension and other postretirement benefit liabilities	202,938	228,129	215,007
Derivative instruments	921	609	2,998
Operating lease liabilities	80,830	772	654
Other non-current liabilities	122,684	123,260	123,259
Total deferred credits and other non-current liabilities	1,363,281	1,287,784	1,255,770
Equity:
Common stock	319,557	319,557	319,634
Retained earnings	496,175	513,372	487,530
Accumulated other comprehensive loss	(10,227)	(10,733)	(8,210)
Total equity	805,505	822,196	798,954
Total liabilities and equity	$ 3,463,367	$ 3,321,487	$ 3,149,641