Financial Instruments and Financial Risk Management - Additional Information (Details) - EUR (€) |
3 Months Ended | 6 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2025 |
Mar. 31, 2026 |
Mar. 31, 2025 |
Sep. 30, 2025 |
|
| Disclosure of fair value measurement [abstract] | |||||
| Increase (decrease) in fair value recorded through Finance cost, net | € (14,700,000) | € (5,600,000) | € (4,500,000) | € (8,800,000) | |
| Percentage of yield volatility | 40.00% | 40.00% | |||
| Percentage of credit spread | 1.07% | 1.36% | |||
| Percentge of increase decrease in yield volatility | 2.50% | 2.50% | |||
| Increase/decrease in fair value | € 1,100,000 | € 1,300,000 | |||
| Transfers out of level 1 into level 2 of fair value hierarchy, liabilities held at end of reporting period | € 0 | € 0 | |||