Commitments and Contingencies - Schedule of Gas Purchase and Pipeline Capacity Purchase and Release Commitments (Details) - Northwest Natural Gas Company [Member] $ in Thousands	Dec. 31, 2021 USD ($)
Gas Purchase Agreements [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
2018	$ 168,296
2019	6,376
2020	6,426
2021	12,076
2022	12,133
Thereafter	203,500
Total	408,807
Less: Amount representing interest	44,571
Total at present value	364,236
Pipeline Capacity Purchase Agreements [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
2018	85,335
2019	87,449
2020	80,923
2021	78,449
2022	63,608
Thereafter	507,666
Total	903,430
Less: Amount representing interest	119,202
Total at present value	784,228
Pipeline Capacity Release Agreements [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
2018	7,596
2019	4,036
2020	4,036
2021	3,363
2022	0
Thereafter	0
Total	19,031
Less: Amount representing interest	382
Total at present value	$ 18,649