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Intangible Assets (Tables) | 12 Months Ended
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Sep. 30, 2025
Goodwill and Intangible Assets Disclosure [Abstract] |
Schedule of Gross and Net Carrying Values of Intangible Assets | The gross and net carrying values of intangible assets as of the balance sheet dates, by major intangible asset class are as follows (in millions):
| September 30, 2025 |  | September 30, 2024 |
| Gross Amount |  | Accumulated Amortization |  | Net Amount |  | Gross Amount |  | Accumulated Amortization |  | Net Amount |
Intangible assets subject to amortization: |  |  |  |  |  |  |  |  |  |  |  |
Trade/domain names and other licenses | $ | 10.6 |  |  | $ | (4.9) |  |  | $ | 5.7 |  |  | $ | 4.1 |  |  | $ | (3.2) |  |  | $ | 0.9 |  |
Software programs/platforms | 2.4 |  |  | (2.0) |  |  | 0.4 |  |  | 4.9 |  |  | (4.1) |  |  | 0.8 |  |
Client base | 445.0 |  |  | (19.2) |  |  | 425.8 |  |  | 37.7 |  |  | (25.6) |  |  | 12.1 |  |
Total intangible assets subject to amortization | 458.0 |  |  | (26.1) |  |  | 431.9 |  |  | 46.7 |  |  | (32.9) |  |  | 13.8 |  |
Intangible assets not subject to amortization |  |  |  |  |  |  |  |  |  |  |  |
Website domains | 2.3 |  |  | — |  |  | 2.3 |  |  | 2.1 |  |  | — |  |  | 2.1 |  |
Business licenses | 3.7 |  |  | — |  |  | 3.7 |  |  | 3.7 |  |  | — |  |  | 3.7 |  |
Total intangible assets not subject to amortization | 6.0 |  |  | — |  |  | 6.0 |  |  | 5.8 |  |  | — |  |  | 5.8 |  |
Total intangible assets | $ | 464.0 |  |  | $ | (26.1) |  |  | $ | 437.9 |  |  | $ | 52.5 |  |  | $ | (32.9) |  |  | $ | 19.6 |  |
Schedule of Expected Amortization Expense | As of September 30, 2025, estimated future amortization expense was as follows:
(in millions) |
Fiscal 2026 | $ | 31.9 |
Fiscal 2027 | 28.9 |
Fiscal 2028 | 27.8 |
Fiscal 2029 | 27.0 |
Fiscal 2030 and thereafter | 316.3 |
| $ | 431.9 |

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- Definition Tabular disclosure of assets, excluding financial assets and goodwill, lacking physical substance with a finite life or exist in perpetuity, by either major class or business segment. + References No definition available. + Details
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- Definition Tabular disclosure of the amount of amortization expense expected to be recorded in succeeding fiscal years for finite-lived intangible assets. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Name Accounting Standards Codification -Section 55 -Paragraph 40 -SubTopic 30 -Topic 350 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482640/350-30-55-40 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 350 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482665/350-30-50-2 + Details
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