Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019
Current assets:
Cash and cash equivalents	$ 471,079	$ 9,648	$ 12,817
Accounts receivable	78,083	67,137	93,617
Accrued unbilled revenue	41,871	56,192	36,147
Allowance for uncollectible accounts	(1,335)	(673)	(1,301)
Regulatory assets	37,815	41,929	46,317
Derivative instruments	2,257	6,802	7,890
Inventories	34,390	43,985	19,540
Gas reserves	14,351	15,278	16,157
Income Taxes Receivable, Current	0	256	6,000
Other current assets	26,460	38,004	20,293
Discontinued operations current assets	15,296	15,134	14,632
Total current assets	720,267	293,692	272,109
Non-current assets:
Property, plant, and equipment	3,551,065	3,476,746	3,439,460
Less: Accumulated depreciation	1,050,850	1,037,847	1,005,117
Property, Plant and Equipment, Net	2,500,215	2,438,899	2,434,343
Gas reserves	45,234	48,394	61,907
Regulatory assets	328,024	343,146	327,194
Derivative instruments	2,451	3,337	541
Other investments	61,928	63,333	63,829
Operating lease right of use asset	79,522	2,950	6,163
Assets under sales-type leases	146,937	146,310	990
Goodwill	69,220	49,929	8,954
Other non-current assets	47,729	38,464	15,087
Total non-current assets	3,281,260	3,134,762	2,919,008
Total assets	4,001,527	3,428,454	3,191,117
Current liabilities:
Short-term debt	550,000	149,100	176,391
Current maturities of long-term debt	202	75,109	104,158
Accounts payable	86,766	113,370	103,207
Taxes accrued	23,837	11,971	11,004
Interest accrued	9,396	7,451	9,233
Regulatory liabilities	47,137	44,657	46,770
Derivative instruments	5,036	2,000	2,845
Operating lease liabilities	1,071	2,101	4,656
Other current liabilities	62,624	62,705	54,543
Discontinued operations current liabilities	12,801	13,709	13,282
Total current liabilities	798,870	482,173	526,089
Long-term debt	953,962	805,955	632,484
Deferred credits and other non-current liabilities:
Deferred tax liabilities	300,168	295,643	293,662
Regulatory liabilities	623,219	625,717	600,698
Pension and other postretirement benefit liabilities	224,490	228,129	220,732
Derivative instruments	939	609	1,161
Operating lease liabilities	79,105	841	1,495
Other non-current liabilities	119,033	123,388	120,569
Total deferred credits and other non-current liabilities	1,346,954	1,274,327	1,238,317
Commitments and contingencies (see Note 16 and Note 17)
Equity:
Common stock	561,264	558,282	459,932
Retained earnings	351,050	318,450	342,734
Accumulated other comprehensive loss	(10,573)	(10,733)	(8,439)
Total equity	901,741	865,999	794,227
Total liabilities and equity	4,001,527	3,428,454	3,191,117
Northwest Natural Gas Company [Member]
Current assets:
Cash and cash equivalents	432,255	5,919	6,833
Accounts receivable	77,340	66,823	93,502
Accrued unbilled revenue	41,809	56,139	36,085
Receivables from affiliates	2,718	787	4,247
Allowance for uncollectible accounts	(1,334)	(672)	(1,300)
Regulatory assets	37,815	41,929	46,317
Derivative instruments	2,257	6,802	7,890
Inventories	34,279	43,896	19,528
Gas reserves	14,351	15,278	16,157
Other current assets	26,290	33,258	19,474
Total current assets	667,780	270,159	248,733
Non-current assets:
Property, plant, and equipment	3,509,049	3,456,075	3,435,304
Less: Accumulated depreciation	1,049,135	1,036,593	1,004,812
Property, Plant and Equipment, Net	2,459,914	2,419,482	2,430,492
Gas reserves	45,234	48,394	61,907
Regulatory assets	328,024	343,146	327,194
Derivative instruments	2,451	3,337	541
Other investments	48,450	49,837	50,212
Operating lease right of use asset	79,383	2,760	5,903
Assets under sales-type leases	146,937	146,310	990
Other non-current assets	47,223	38,062	14,656
Total non-current assets	3,157,616	3,051,328	2,891,895
Total assets	3,825,396	3,321,487	3,140,628
Current liabilities:
Short-term debt	450,000	125,100	176,300
Current maturities of long-term debt	0	74,907	104,084
Accounts payable	85,604	111,641	102,232
Payables to affiliates	21,353	1,546	1,385
Taxes accrued	11,621	11,717	10,869
Interest accrued	9,368	7,441	9,225
Regulatory liabilities	47,137	44,657	46,770
Derivative instruments	5,036	2,000	2,845
Operating lease liabilities	984	1,979	4,477
Other current liabilities	61,218	61,438	53,155
Total current liabilities	692,321	442,426	511,342
Long-term debt	917,146	769,081	630,370
Deferred credits and other non-current liabilities:
Deferred tax liabilities	312,436	309,297	307,704
Regulatory liabilities	622,375	625,717	600,698
Pension and other postretirement benefit liabilities	224,490	228,129	220,732
Derivative instruments	939	609	1,161
Operating lease liabilities	79,052	772	1,413
Other non-current liabilities	118,898	123,260	120,465
Total deferred credits and other non-current liabilities	1,358,190	1,287,784	1,252,173
Equity:
Common stock	319,557	319,557	226,452
Retained earnings	548,755	513,372	528,730
Accumulated other comprehensive loss	(10,573)	(10,733)	(8,439)
Total equity	857,739	822,196	746,743
Total liabilities and equity	$ 3,825,396	$ 3,321,487	$ 3,140,628