v3.26.1
Significant Accounting Policies - Schedule of Credit Losses - ASU 2016-13 (Details)
$ in Thousands
 6 Months Ended
Jun. 30, 2026
USD ($)
NW Natural  
Accounts Receivable, Allowance for Credit Loss [Roll Forward]  
Beginning Balance $ 3,048
Provision recorded, net of adjustments 256
Write-offs recognized, net of recoveries (830)
Ending Balance 2,474
Other - NW Holdings  
Accounts Receivable, Allowance for Credit Loss [Roll Forward]  
Beginning Balance 1,020
Provision recorded, net of adjustments 555
Write-offs recognized, net of recoveries (194)
Ending Balance 1,381
Total NW Holdings  
Accounts Receivable, Allowance for Credit Loss [Roll Forward]  
Beginning Balance 4,068
Provision recorded, net of adjustments 811
Write-offs recognized, net of recoveries (1,024)
Ending Balance 3,855
Residential | NW Natural  
Accounts Receivable, Allowance for Credit Loss [Roll Forward]  
Beginning Balance 2,280
Provision recorded, net of adjustments 300
Write-offs recognized, net of recoveries (631)
Ending Balance 1,949
Commercial | NW Natural  
Accounts Receivable, Allowance for Credit Loss [Roll Forward]  
Beginning Balance 374
Provision recorded, net of adjustments 39
Write-offs recognized, net of recoveries (203)
Ending Balance 210
Industrial | NW Natural  
Accounts Receivable, Allowance for Credit Loss [Roll Forward]  
Beginning Balance 46
Provision recorded, net of adjustments 17
Write-offs recognized, net of recoveries 0
Ending Balance 63
Accrued unbilled and other | NW Natural  
Accounts Receivable, Allowance for Credit Loss [Roll Forward]  
Beginning Balance 348
Provision recorded, net of adjustments (100)
Write-offs recognized, net of recoveries 4
Ending Balance $ 252