Valuation Allowances and Reserves (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Entity Information [Line Items]
Allowance for Doubtful Accounts Receivable, beginning of period	$ 3,219	$ 673	$ 977
Valuation Allowances and Reserves, Charged to Cost and Expense	724	890	450
Valuation Allowances and Reserves, Charged to Other Accounts	(219)	2,333	0
SEC Schedule, 12-09, Valuation Allowances and Reserves, Deduction	1,706	677	754
Allowance for Doubtful Accounts Receivable, end of period	2,018	3,219	673
Northwest Natural Gas Company [Member]
Entity Information [Line Items]
Allowance for Doubtful Accounts Receivable, beginning of period	3,107	672	975
Valuation Allowances and Reserves, Charged to Cost and Expense	780	779	450
Valuation Allowances and Reserves, Charged to Other Accounts	(219)	2,333	0
SEC Schedule, 12-09, Valuation Allowances and Reserves, Deduction	1,706	677	753
Allowance for Doubtful Accounts Receivable, end of period	$ 1,962	$ 3,107	$ 672