Supplemental Cash Flow - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022	Dec. 31, 2021
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents		$ 137,759	$ 29,270	$ 17,209
Restricted Cash		17,324	11,694	12,826
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents		155,083	40,964	30,035	$ 27,120
Northwest Natural Gas Company [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents		131,778	12,977	10,267
Restricted Cash		17,299	11,694	12,826
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents		149,077	$ 24,671	$ 23,093	$ 20,832
Money Market Funds, at Carrying Value		$ 116,500
Northwest Natural Gas Company [Member] | Subsequent Event [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Payments of Dividends	$ 25,000