Debt Short-term Debt - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 2022
Short-term Debt [Line Items]
Short-term debt	$ 71,000	$ 258,200	$ 141,000
Northwest Natural Gas Company [Member]
Short-term Debt [Line Items]
Short-term debt	0	170,200	53,000
Line of Credit [Member]
Short-term Debt [Line Items]
Short-term debt	$ 71,000	$ 88,000	$ 88,000
Debt, Weighted Average Interest Rate	6.40%	5.30%	4.70%
Commercial Paper [Member] | Northwest Natural Gas Company [Member]
Short-term Debt [Line Items]
Short-term debt	$ 0	$ 170,200	$ 53,000
Debt, Weighted Average Interest Rate	0.00%	4.60%	3.30%