Leases - Lease Expense - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2024 |
Jun. 30, 2023 |
Jun. 30, 2024 |
Jun. 30, 2023 |
|
| Lease Expense [Abstract] | ||||
| Operating Lease, Expense | $ 1,921 | $ 1,830 | $ 3,828 | $ 3,645 |
| Short-term Lease, Cost | $ 384 | 278 | $ 465 | 358 |
| Lessee, Operating Lease, Maximum Term of Short-term Leases not recorded on the Balance Sheet | 12 months | 12 months | ||
| Minimum [Member] | ||||
| Operating Lease Terms [Abstract] | ||||
| Lessee, Operating Lease, Term of Contract | 5 months | 5 months | ||
| Maximum [Member] | ||||
| Operating Lease Terms [Abstract] | ||||
| Lessee, Operating Lease, Term of Contract | 16 years | 16 years | ||
| Northwest Natural Gas Company [Member] | ||||
| Lease Expense [Abstract] | ||||
| Operating Lease, Expense | $ 1,875 | 1,790 | $ 3,737 | 3,565 |
| Short-term Lease, Cost | 384 | 278 | 465 | 358 |
| Other Northwest Holdings [Member] | Corporate, Non-Segment [Member] | ||||
| Lease Expense [Abstract] | ||||
| Operating Lease, Expense | $ 46 | $ 40 | $ 91 | $ 80 |