v3.26.1
Leases - weighted-Average Remaining Lease Terms and Weighted-Average Discount Rates (Details) - NW Natural
Jun. 30, 2026
Dec. 31, 2025
Jun. 30, 2025
Lessee, Lease, Description [Line Items]      
Weighted-average remaining lease term (years) 13 years 9 months 18 days 14 years 3 months 18 days 14 years 9 months 18 days
Weighted-average discount rate 7.30% 7.30% 7.30%