Deferred Tax Liability, Regulatory Excess, Return Term

No definition available.

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- Definition

Amount, after deferred tax asset, of deferred tax liability attributable to taxable differences without jurisdictional netting.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482685/740-10-50-2

+ Details

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- Definition

Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482685/740-10-50-12

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 231
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482663/740-10-55-231

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

The amount for the individual regulatory liability as itemized in a table of regulatory liabilities as of the end of the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 980
-SubTopic 405
-Name Accounting Standards Codification
-Section 25
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477571/980-405-25-1

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Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
Income Taxes (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Mar. 31, 2025	Mar. 31, 2026	Mar. 31, 2025	Sep. 30, 2025
Income Tax Contingency [Line Items]
Effective income tax rate (in percentage)	20.70%	19.50%	20.40%	19.00%
Deferred tax liabilities, net	$ 103,400		$ 103,400
Regulatory liabilities	1,277,855		1,277,855		$ 1,269,648
Regulatory excess deferred taxes
Income Tax Contingency [Line Items]
Regulatory liabilities	152,503		152,503		190,274
Regulatory excess deferred taxes \| Other Current Liabilities
Income Tax Contingency [Line Items]
Deferred tax liabilities, net	49,300		49,300		$ 72,800
Regulatory excess deferred taxes, to be returned, tranche one
Income Tax Contingency [Line Items]
Deferred tax liabilities, net	55,600		$ 55,600
Regulatory excess deferred taxes, to be returned, tranche one \| Minimum
Income Tax Contingency [Line Items]
Return basis, term (in years)			36 months
Regulatory excess deferred taxes, to be returned, tranche one \| Maximum
Income Tax Contingency [Line Items]
Return basis, term (in years)			60 months
Regulatory excess deferred taxes, to be returned, tranche two
Income Tax Contingency [Line Items]
Regulatory liabilities	46,800		$ 46,800
Regulatory excess deferred taxes, to be returned, tranche two \| Minimum
Income Tax Contingency [Line Items]
Return basis, term (in years)			15 years
Regulatory excess deferred taxes, to be returned, tranche two \| Maximum
Income Tax Contingency [Line Items]
Return basis, term (in years)			46 years
Regulatory excess deferred taxes, to be returned, tranche three
Income Tax Contingency [Line Items]
Deferred tax liabilities, net	$ 1,000		$ 1,000