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Derivative Financial Instruments and Fair Value Measurements - Narrative (Details) - USD ($) $ in Millions | 9 Months Ended |  |
--- | --- | --- | ---
Jun. 30, 2025 | Jun. 30, 2024 | Sep. 30, 2024 | Jun. 30, 2022
Derivative [Line Items] |  |  |  |
Loss recorded representing decrease in fair value | $ 6.9 | $ 1.6 |  |
Interest Rate Swap | Cash Flow Hedging |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative, basis spread on variable rate (as percent) |  |  |  | 3.465%
Interest Rate Swap | Cash Flow Hedging | Designated as Hedging Instrument |  |  |  |
Derivative [Line Items] |  |  |  |
Material losses recognized in income | 0.0 | $ 0.0 |  |
Interest Rate Cap | Cash Flow Hedging |  |  |  |
Derivative [Line Items] |  |  |  |
Notional value |  |  |  | $ 300.0
Interest Rate Cap | Cash Flow Hedging | Maximum |  |  |  |
Derivative [Line Items] |  |  |  |
Fixed interest rate (as percent) |  |  |  | 3.465%
February 2023 | United States of America, Dollars | Interest Rate Swap | Cash Flow Hedging | Designated as Hedging Instrument |  |  |  |
Derivative [Line Items] |  |  |  |
Notional value | $ 400.0 |  | $ 400.0 |
Fixed interest rate (as percent) | 1.283% |  | 1.283% |

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- Definition Amount of gain (loss) from the increase (decrease) in fair value of derivative and nonderivative instruments designated as fair value hedging instruments recognized in the income statement. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 815 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 4A -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480434/815-10-50-4A Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 220 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 21 -Subparagraph (i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147476148/220-40-50-21 + Details
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- Definition Amount of gain (loss) from excluded component of derivative hedge, recognized in earnings. Excludes recognition under systematic and rational method. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 815 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 4A -Subparagraph (b)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480434/815-10-50-4A Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 815 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 4C -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480434/815-10-50-4C Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 220 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 21 -Subparagraph (i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147476148/220-40-50-21 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Name Accounting Standards Codification -Section 45 -Paragraph 1A -Subparagraph (b) -SubTopic 20 -Topic 815 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480627/815-20-45-1A + Details
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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 Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 815 -SubTopic 20 -Name Accounting Standards Codification -Section 25 -Paragraph 6A -Publisher FASB -URI https://asc.fasb.org/1943274/2147480682/815-20-25-6A Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 815 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480237/815-40-50-5 + Details
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