Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019
Current assets:
Cash and cash equivalents	$ 137,057	$ 9,648	$ 60,885
Accounts receivable	35,196	67,137	42,670
Accrued unbilled revenue	15,393	56,192	14,840
Allowance for uncollectible accounts	(1,592)	(673)	(814)
Regulatory assets	30,021	41,929	46,688
Derivative instruments	5,996	6,802	2,186
Inventories	44,009	43,985	23,100
Gas reserves	13,646	15,278	17,206
Income Taxes Receivable, Current	0	256	0
Other current assets	20,318	38,004	18,296
Discontinued operations current assets	16,392	15,134	14,001
Total current assets	316,436	293,692	239,058
Non-current assets:
Property, plant, and equipment	3,608,902	3,476,746	3,355,811
Less: Accumulated depreciation	1,062,299	1,037,847	1,016,185
Property, Plant and Equipment, Net	2,546,603	2,438,899	2,339,626
Gas reserves	41,459	48,394	56,171
Regulatory assets	324,358	343,146	318,340
Derivative instruments	3,958	3,337	670
Other investments	62,130	63,333	62,815
Operating lease right of use asset	78,566	2,950	5,013
Assets under sales-type leases	146,208	146,310	148,886
Goodwill	70,183	49,929	49,393
Other non-current assets	51,446	38,464	18,159
Total non-current assets	3,324,911	3,134,762	2,999,073
Total assets	3,641,347	3,428,454	3,238,131
Current liabilities:
Short-term debt	233,000	149,100	20,080
Current maturities of long-term debt	35,209	75,109	104,396
Accounts payable	79,903	113,370	76,429
Taxes accrued	18,535	11,971	7,003
Interest accrued	7,234	7,451	7,826
Regulatory liabilities	41,126	44,657	32,484
Derivative instruments	3,067	2,000	4,650
Operating lease liabilities	931	2,101	4,271
Other current liabilities	54,323	62,705	36,612
Discontinued operations current liabilities	13,574	13,709	13,279
Total current liabilities	486,902	482,173	307,030
Long-term debt	918,887	805,955	806,001
Deferred credits and other non-current liabilities:
Deferred tax liabilities	297,995	295,643	292,791
Regulatory liabilities	632,400	625,717	605,036
Pension and other postretirement benefit liabilities	218,493	228,129	217,909
Derivative instruments	1,658	609	2,062
Operating lease liabilities	80,159	841	721
Other non-current liabilities	120,852	123,388	129,835
Total deferred credits and other non-current liabilities	1,351,557	1,274,327	1,248,354
Commitments and contingencies (see Note 16 and Note 17)
Equity:
Common stock	562,766	558,282	555,052
Retained earnings	331,648	318,450	330,018
Accumulated other comprehensive loss	(10,413)	(10,733)	(8,324)
Total equity	884,001	865,999	876,746
Total liabilities and equity	3,641,347	3,428,454	3,238,131
Northwest Natural Gas Company [Member]
Current assets:
Cash and cash equivalents	120,284	5,919	57,864
Accounts receivable	33,985	66,823	42,180
Accrued unbilled revenue	15,236	56,139	14,730
Receivables from affiliates	563	787	289
Allowance for uncollectible accounts	(1,591)	(672)	(812)
Regulatory assets	30,021	41,929	46,688
Derivative instruments	5,996	6,802	2,186
Inventories	43,619	43,896	22,999
Gas reserves	13,646	15,278	17,206
Other current assets	20,287	33,258	18,259
Total current assets	282,046	270,159	221,589
Non-current assets:
Property, plant, and equipment	3,564,707	3,456,075	3,337,005
Less: Accumulated depreciation	1,059,760	1,036,593	1,015,761
Property, Plant and Equipment, Net	2,504,947	2,419,482	2,321,244
Gas reserves	41,459	48,394	56,171
Regulatory assets	324,320	343,146	318,340
Derivative instruments	3,958	3,337	670
Other investments	48,673	49,837	49,281
Operating lease right of use asset	78,464	2,760	4,797
Assets under sales-type leases	146,208	146,310	148,886
Other non-current assets	50,629	38,062	17,715
Total non-current assets	3,198,658	3,051,328	2,917,104
Total assets	3,480,704	3,321,487	3,138,693
Current liabilities:
Short-term debt	153,000	125,100	0
Current maturities of long-term debt	0	74,907	104,359
Accounts payable	77,993	111,641	74,918
Payables to affiliates	18,450	1,546	6,878
Taxes accrued	7,376	11,717	6,903
Interest accrued	7,156	7,441	7,675
Regulatory liabilities	41,126	44,657	32,484
Derivative instruments	3,067	2,000	4,650
Operating lease liabilities	868	1,979	4,141
Other current liabilities	52,939	61,438	35,113
Total current liabilities	361,975	442,426	277,121
Long-term debt	917,012	769,081	768,947
Deferred credits and other non-current liabilities:
Deferred tax liabilities	309,977	309,297	307,133
Regulatory liabilities	631,531	625,717	605,036
Pension and other postretirement benefit liabilities	218,493	228,129	217,909
Derivative instruments	1,658	609	2,062
Operating lease liabilities	80,120	772	634
Other non-current liabilities	120,569	123,260	129,736
Total deferred credits and other non-current liabilities	1,362,348	1,287,784	1,262,510
Equity:
Common stock	319,557	319,557	319,634
Retained earnings	530,225	513,372	518,805
Accumulated other comprehensive loss	(10,413)	(10,733)	(8,324)
Total equity	839,369	822,196	830,115
Total liabilities and equity	$ 3,480,704	$ 3,321,487	$ 3,138,693