Income Tax - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Income taxes at statutory rates (federal and state)	$ 312	$ 460	$ 20,644	$ 16,243
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount	211	161	8,360	6,674
Differences required to be flowed-through by regulatory commissions	(161)	(62)	(3,070)	(3,235)
Other, net	(119)	(89)	(544)	(289)
Total provision for income taxes on continuing operations	$ 243	$ 470	$ 25,390	$ 19,393
Effective tax rate for continuing operations	16.30%	21.50%	25.80%	25.10%
Northwest Natural Gas Company [Member]
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Income taxes at statutory rates (federal and state)	$ 442	$ 744	$ 21,854	$ 16,859
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount	217	219	8,623	6,803
Differences required to be flowed-through by regulatory commissions	(160)	(62)	(3,069)	(3,235)
Other, net	(177)	(91)	(664)	(294)
Total provision for income taxes on continuing operations	$ 322	$ 810	$ 26,744	$ 20,133
Effective tax rate for continuing operations	15.30%	22.90%	25.70%	25.10%