Organization and Principles of Consolidation Organization and Principles of Consolidation (Details) $ in Thousands	7 Months Ended
Sep. 30, 2018 USD ($)
Northwest Natural Holding Company [Member]
Proceeds from Contributions from Parent	$ 20,000

The cash inflow from parent as a source of financing that is recorded as additional paid in capital.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3255-108585

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