Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018
Current assets:
Cash and cash equivalents	$ 60,885	$ 12,633	$ 8,755
Accounts receivable	42,670	66,970	31,512
Accrued unbilled revenue	14,840	57,827	13,995
Allowance for uncollectible accounts	(814)	(977)	(657)
Regulatory assets	46,688	41,930	41,092
Derivative instruments	2,186	9,001	2,044
Inventories	23,100	44,149	43,109
Gas reserves	17,206	16,647	16,579
Income Taxes Receivable, Current	0	6,000	0
Other current assets	18,296	28,472	11,672
Discontinued operations - current assets	14,001	13,269	12,743
Total current assets	239,058	295,921	180,844
Non-current assets:
Property, plant, and equipment	3,355,811	3,414,490	3,298,856
Less: Accumulated depreciation	1,016,185	993,118	984,998
Property, Plant and Equipment, Net	2,339,626	2,421,372	2,313,858
Gas reserves	56,171	66,197	75,362
Regulatory assets	318,340	371,786	339,177
Derivative instruments	670	725	1,077
Other investments	62,815	63,558	64,854
Operating lease right of use asset	5,013	0	0
Assets under sales-type leases	148,886	0	0
Goodwill	49,393	8,954	0
Other non-current assets	18,159	14,149	11,588
Total non-current assets	2,999,073	2,946,741	2,805,916
Total assets	3,238,131	3,242,662	2,986,760
Current liabilities:
Short-term debt	20,080	217,620	47,100
Current maturities of long-term debt	104,396	29,989	74,785
Accounts payable	76,429	115,878	70,551
Taxes accrued	7,003	11,023	6,916
Interest accrued	7,826	7,306	6,652
Regulatory liabilities	32,484	47,436	34,275
Derivative instruments	4,650	12,381	11,744
Operating lease liabilities	4,271	0	0
Other current liabilities	36,612	54,492	32,935
Discontinued operations current liabilities	13,279	12,959	12,922
Total current liabilities	307,030	509,084	297,880
Long-term debt	806,001	706,247	683,895
Deferred credits and other non-current liabilities:
Deferred tax liabilities	292,791	280,463	281,028
Regulatory liabilities	605,036	611,560	602,294
Pension and other postretirement benefit liabilities	217,909	221,886	218,061
Derivative instruments	2,062	3,025	3,913
Operating lease liabilities	721	0	0
Other non-current liabilities	129,835	147,763	140,163
Discontinued operations non-current liabilities			12,700
Total deferred credits and other non-current liabilities	1,248,354	1,264,697	1,245,459
Commitments and contingencies (see Note 16 and Note 17)
Equity:
Common stock	555,052	457,640	452,195
Retained earnings	330,018	312,182	315,462
Accumulated other comprehensive loss	(8,324)	(7,188)	(8,131)
Total equity	876,746	762,634	759,526
Total liabilities and equity	3,238,131	3,242,662	2,986,760
Northwest Natural Gas Company [Member]
Current assets:
Cash and cash equivalents	57,864	7,947	8,322
Accounts receivable	42,180	66,824	31,512
Accrued unbilled revenue	14,730	57,773	13,995
Receivables from affiliates	289	4,166	265
Allowance for uncollectible accounts	(812)	(975)	(657)
Regulatory assets	46,688	41,930	41,092
Derivative instruments	2,186	9,001	2,044
Inventories	22,999	44,126	43,109
Gas reserves	17,206	16,647	16,579
Other current assets	18,259	25,347	11,603
Discontinued operations - current assets	0	0	5,873
Total current assets	221,589	272,786	173,737
Non-current assets:
Property, plant, and equipment	3,337,005	3,410,439	3,298,481
Less: Accumulated depreciation	1,015,761	992,855	984,791
Property, Plant and Equipment, Net	2,321,244	2,417,584	2,313,690
Gas reserves	56,171	66,197	75,362
Regulatory assets	318,340	371,786	339,177
Derivative instruments	670	725	1,077
Other investments	49,281	49,922	51,181
Operating lease right of use asset	4,797	0	0
Assets under sales-type leases	148,886	0	0
Other non-current assets	17,715	13,736	11,578
Discontinued operations - non-current assets	0	0	25,037
Total non-current assets	2,917,104	2,919,950	2,817,102
Total assets	3,138,693	3,192,736	2,990,839
Current liabilities:
Short-term debt	0	217,500	47,100
Current maturities of long-term debt	104,359	29,989	74,785
Accounts payable	74,918	114,937	70,155
Payables to affiliates	6,878	523	3,811
Taxes accrued	6,903	10,990	6,887
Interest accrued	7,675	7,273	6,652
Regulatory liabilities	32,484	47,436	34,275
Derivative instruments	4,650	12,381	11,744
Operating lease liabilities	4,141	0	0
Other current liabilities	35,113	53,027	31,934
Discontinued operations current liabilities	0	0	2,702
Total current liabilities	277,121	494,056	290,045
Long-term debt	768,947	704,134	683,895
Deferred credits and other non-current liabilities:
Deferred tax liabilities	307,133	294,739	296,050
Regulatory liabilities	605,036	611,560	602,294
Pension and other postretirement benefit liabilities	217,909	221,886	218,061
Derivative instruments	2,062	3,025	3,913
Operating lease liabilities	634	0	0
Other non-current liabilities	129,736	147,668	140,073
Discontinued operations non-current liabilities	0	0	3,018
Total deferred credits and other non-current liabilities	1,262,510	1,278,878	1,257,373
Equity:
Common stock	319,634	226,452	452,195
Retained earnings	518,805	496,404	315,462
Accumulated other comprehensive loss	(8,324)	(7,188)	(8,131)
Total equity	830,115	715,668	759,526
Total liabilities and equity	$ 3,138,693	$ 3,192,736	$ 2,990,839