Consolidated Statement of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Operating activities:
Net income	$ 24,995	$ 28,745
Adjustments to reconcile net income to cash provided by operations:
Depreciation and amortization	67,334	63,507
Regulatory amortization of gas reserves	14,474	12,056
Deferred income taxes	2,471	3,954
Qualified defined benefit pension plan expense	10,464	4,450
Contributions to qualified defined benefit pension plans	(7,810)	(11,690)
Deferred environmental expenditures, net	(10,992)	(10,547)
Amortization of environmental remediation	7,258	7,528
Regulatory revenue recovery deferral from the TCJA	742	6,983
Regulatory disallowance of pension costs	10,500	0
Other	9,058	1,541
Changes in assets and liabilities:
Receivables, net	80,205	83,194
Inventories	(3,293)	(5,134)
Income and other taxes	21,510	(5,809)
Accounts payable	(31,767)	(22,929)
Interest accrued	3,100	2,680
Deferred gas costs	(47,085)	2,372
Decoupling mechanism	11,095	2,915
Other, net	(6,713)	(6,503)
Discontinued operations	(255)	1,216
Cash provided by operating activities	155,291	158,529
Investing activities:
Capital expenditures	(152,993)	(158,795)
Acquisitions, net of cash acquired	(56,189)	136
Other	(15,460)	(1,797)
Discontinued operations	(648)	(619)
Cash used in investing activities	(225,290)	(161,075)
Financing activities:
Proceeds from stock options exercised	1,723	1,368
Proceeds from common stock issued	93,182	0
Long-term debt issued	175,000	50,000
Long-term debt retired	(10,000)	(22,000)
Change in short-term debt	(152,040)	46,300
Cash dividend payments on common stock	(39,605)	(38,387)
Payments for the Repurchase of Common Stock Related to Acquisitions	0	7,951
Other	(372)	(291)
Net Cash Provided by (Used in) Financing Activities	67,888	29,039
Increase in cash and cash equivalents	(2,111)	26,493
Cash and cash equivalents, beginning of period	12,633	3,472
Cash and cash equivalents, end of period	10,522	29,965
Supplemental disclosure of cash flow information:
Interest paid, net of capitalization	27,736	22,821
Income taxes paid (refunded), net	(6,096)	22,047
Northwest Natural Gas Company [Member]
Operating activities:
Net income	29,361	28,745
Adjustments to reconcile net income to cash provided by operations:
Depreciation and amortization	66,821	63,412
Regulatory amortization of gas reserves	14,474	12,056
Deferred income taxes	(5)	2,349
Qualified defined benefit pension plan expense	10,464	4,450
Contributions to qualified defined benefit pension plans	(7,810)	(11,690)
Deferred environmental expenditures, net	(10,992)	(10,547)
Amortization of environmental remediation	7,258	7,528
Regulatory revenue recovery deferral from the TCJA	742	6,983
Regulatory disallowance of pension costs	10,500	0
Other	7,903	1,909
Changes in assets and liabilities:
Receivables, net	83,581	83,116
Inventories	(3,321)	(5,504)
Income and other taxes	13,505	(5,810)
Accounts payable	(30,281)	(22,738)
Interest accrued	3,132	2,680
Deferred gas costs	(47,085)	2,372
Decoupling mechanism	11,095	2,915
Other, net	(4,878)	(6,368)
Discontinued operations	0	2,077
Cash provided by operating activities	154,464	157,935
Investing activities:
Capital expenditures	(151,915)	(158,795)
Other	(15,460)	(2,797)
Discontinued operations	0	(19,606)
Cash used in investing activities	(167,375)	(181,198)
Financing activities:
Proceeds from stock options exercised	0	1,368
Capital contribution from parent	93,182	0
Long-term debt issued	140,000	50,000
Long-term debt retired	(10,000)	(22,000)
Change in short-term debt	(172,000)	46,300
Cash dividend payments on common stock	(39,601)	(38,387)
Other	(343)	(291)
Discontinued operations	0	(7,951)
Net Cash Provided by (Used in) Financing Activities	11,238	29,039
Increase in cash and cash equivalents	(1,673)	5,776
Cash and cash equivalents, beginning of period	7,947	3,110
Cash and cash equivalents, end of period	6,274	8,886
Supplemental disclosure of cash flow information:
Interest paid, net of capitalization	26,927	22,821
Income taxes paid (refunded), net	$ (6,096)	$ 22,047