Fair Value Measurement - Additional Information (Details) - EUR (€) |
12 Months Ended | |
|---|---|---|
Sep. 30, 2024 |
Sep. 30, 2023 |
|
| Disclosure of fair value measurement [abstract] | ||
| Transfers out of level 1 into level 2 of fair value hierarchy, liabilities held at end of reporting period | € 0 | € 0 |
| Transfers out of level 2 into level 1 of fair value hierarchy, liabilities held at end of reporting period | 0 | 0 |
| Tax receivable agreement liability | 344,590,000 | € 0 |
| Cash flow hedge reserve of a cumulative loss | € 300,000 | |