Significant Accounting Policies - Narrative (Details)	Jun. 30, 2026 USD ($) lease	Jun. 30, 2025 USD ($)
Accounts Receivable, Noncurrent, Credit Quality Indicator [Line Items]
Money market funds, at carrying value	$ 2,200,000	$ 72,000,000.0
Number of net investments in sales-type leases \| lease	2
Sales-type lease, net investment in lease, allowance for credit loss	$ 0
NW Natural
Accounts Receivable, Noncurrent, Credit Quality Indicator [Line Items]
Money market funds, at carrying value	$ 2,200,000	$ 69,000,000.0

Investment in short-term money-market instruments (such as commercial paper, banker's acceptances, repurchase agreements, government securities, certificates of deposit, and so forth) which are highly liquid (that is, readily convertible to known amounts of cash) and so near their maturity that they present an insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify as cash equivalents by definition. Original maturity means an original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(1))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant