Commitments and Contingencies - Schedule of Gas Purchase and Pipeline Capacity Purchase and Release Commitments (Details) - Northwest Natural Gas Company [Member] $ in Thousands	Dec. 31, 2023 USD ($)
Gas Purchase Agreements [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
2018	$ 303,682
2019	34,457
2020	34,586
2021	33,830
2022	33,980
Thereafter	208,426
Total	648,961
Less: Amount representing interest	96,491
Total at present value	552,470
Pipeline Capacity Purchase Agreements [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
2018	78,907
2019	81,114
2020	66,972
2021	67,123
2022	63,812
Thereafter	377,175
Total	735,103
Less: Amount representing interest	183,620
Total at present value	551,483
Pipeline Capacity Release Agreements [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
2018	7,543
2019	3,455
2020	0
2021	0
2022	0
Thereafter	0
Total	10,998
Less: Amount representing interest	373
Total at present value	$ 10,625