Leases - Lease Expense - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Lease Expense [Abstract]
Operating Lease, Expense	$ 1,815	$ 1,734
Short-term Lease, Cost	$ 80	163
Lessee, Operating Lease, Maximum Term of Short-term Leases not recorded on the Balance Sheet	12 months
Minimum [Member]
Operating Lease Terms [Abstract]
Lessee, Operating Lease, Term of Contract	6 months
Maximum [Member]
Operating Lease Terms [Abstract]
Lessee, Operating Lease, Term of Contract	17 years
Northwest Natural Gas Company [Member]
Lease Expense [Abstract]
Operating Lease, Expense	$ 1,775	1,727
Short-term Lease, Cost	80	163
Other Northwest Holdings [Member] | Corporate, Non-Segment [Member]
Lease Expense [Abstract]
Operating Lease, Expense	$ 40	$ 7