Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018
Current assets:
Cash and cash equivalents	$ 10,522	$ 12,633	$ 29,965
Accounts receivable	29,617	66,970	25,125
Accrued unbilled revenue	17,934	57,827	16,351
Allowance for uncollectible accounts	(180)	(977)	(394)
Regulatory assets	47,996	41,930	41,241
Derivative instruments	5,987	9,001	2,871
Inventories	41,230	44,149	53,064
Gas reserves	16,392	16,647	16,916
Income Taxes Receivable, Current	0	6,000	0
Other current assets	18,617	28,472	20,376
Discontinued operations - current assets	14,612	13,269	12,644
Total current assets	202,727	295,921	218,159
Non-current assets:
Property, plant, and equipment	3,416,718	3,414,490	3,370,388
Less: Accumulated depreciation	1,027,330	993,118	996,994
Property, Plant and Equipment, Net	2,389,388	2,421,372	2,373,394
Gas reserves	51,978	66,197	70,556
Regulatory assets	313,890	371,786	333,917
Derivative instruments	1,610	725	861
Other investments	63,018	63,558	65,113
Operating lease right of use asset	3,917	0	0
Assets under sales-type leases	147,918	0	0
Goodwill	49,333	8,954	6,563
Other non-current assets	27,839	14,149	12,844
Total non-current assets	3,048,891	2,946,741	2,863,248
Total assets	3,251,618	3,242,662	3,081,407
Current liabilities:
Short-term debt	65,580	217,620	100,500
Current maturities of long-term debt	94,671	29,989	84,940
Accounts payable	76,197	115,878	80,143
Taxes accrued	13,382	11,023	13,074
Interest accrued	10,406	7,306	9,453
Regulatory liabilities	37,573	47,436	37,504
Derivative instruments	4,156	12,381	8,828
Operating lease liabilities	3,171	0	0
Other current liabilities	39,873	54,492	35,497
Discontinued operations current liabilities	13,399	12,959	13,003
Total current liabilities	358,408	509,084	382,942
Long-term debt	806,014	706,247	724,654
Deferred credits and other non-current liabilities:
Deferred tax liabilities	284,625	280,463	274,315
Regulatory liabilities	615,813	611,560	606,175
Pension and other postretirement benefit liabilities	215,007	221,886	212,249
Derivative instruments	2,998	3,025	3,016
Operating lease liabilities	732	0	0
Other non-current liabilities	123,352	147,763	140,475
Discontinued operations non-current liabilities			12,600
Total deferred credits and other non-current liabilities	1,242,527	1,264,697	1,236,230
Commitments and contingencies (see Note 16 and Note 17)
Equity:
Common stock	556,623	457,640	455,499
Retained earnings	296,256	312,182	290,059
Accumulated other comprehensive loss	(8,210)	(7,188)	(7,977)
Total equity	844,669	762,634	737,581
Total liabilities and equity	3,251,618	3,242,662	3,081,407
Northwest Natural Gas Company [Member]
Current assets:
Cash and cash equivalents	6,274	7,947	8,886
Accounts receivable	29,065	66,824	25,003
Accrued unbilled revenue	17,843	57,773	16,351
Receivables from affiliates	1,106	4,166	388
Allowance for uncollectible accounts	(178)	(975)	(392)
Regulatory assets	47,996	41,930	41,241
Derivative instruments	5,987	9,001	2,871
Inventories	41,148	44,126	53,047
Gas reserves	16,392	16,647	16,916
Other current assets	17,519	25,347	20,321
Discontinued operations - current assets	0	0	26,227
Total current assets	183,152	272,786	210,859
Non-current assets:
Property, plant, and equipment	3,397,053	3,410,439	3,366,896
Less: Accumulated depreciation	1,026,631	992,855	996,780
Property, Plant and Equipment, Net	2,370,422	2,417,584	2,370,116
Gas reserves	51,978	66,197	70,556
Regulatory assets	313,890	371,786	333,917
Derivative instruments	1,610	725	861
Other investments	49,503	49,922	51,459
Operating lease right of use asset	3,745	0	0
Assets under sales-type leases	147,918	0	0
Other non-current assets	27,423	13,736	12,740
Discontinued operations - non-current assets	0	0	35,079
Total non-current assets	2,966,489	2,919,950	2,874,728
Total assets	3,149,641	3,192,736	3,085,587
Current liabilities:
Short-term debt	45,500	217,500	100,500
Current maturities of long-term debt	94,633	29,989	84,940
Accounts payable	75,126	114,937	79,608
Payables to affiliates	4,185	523	3,235
Taxes accrued	12,941	10,990	13,034
Interest accrued	10,405	7,273	9,453
Regulatory liabilities	37,573	47,436	37,504
Derivative instruments	4,156	12,381	8,828
Operating lease liabilities	3,075	0	0
Other current liabilities	38,328	53,027	34,403
Discontinued operations current liabilities	0	0	3,769
Total current liabilities	325,922	494,056	375,274
Long-term debt	768,995	704,134	723,820
Deferred credits and other non-current liabilities:
Deferred tax liabilities	298,039	294,739	289,012
Regulatory liabilities	615,813	611,560	606,175
Pension and other postretirement benefit liabilities	215,007	221,886	212,249
Derivative instruments	2,998	3,025	3,016
Operating lease liabilities	654	0	0
Other non-current liabilities	123,259	147,668	140,390
Discontinued operations non-current liabilities	0	0	1,930
Total deferred credits and other non-current liabilities	1,255,770	1,278,878	1,248,912
Equity:
Common stock	319,634	226,452	455,499
Retained earnings	487,530	496,404	290,059
Accumulated other comprehensive loss	(8,210)	(7,188)	(7,977)
Total equity	798,954	715,668	737,581
Total liabilities and equity	$ 3,149,641	$ 3,192,736	$ 3,085,587