v3.25.3
Loans and Borrowings - Reconciliation of Financial Liabilities (Details)
€ in Thousands, $ in Thousands
 12 Months Ended
Sep. 30, 2025
EUR (€)
Sep. 30, 2025
USD ($)
Sep. 30, 2024
EUR (€)
Sep. 30, 2024
USD ($)
Sep. 30, 2023
EUR (€)
Disclosure of reconciliation of liabilities arising from financing activities [line items]          
Beginning balance € 1,194,635   € 1,853,038    
Changes from financing cash flows          
Proceeds from loans and borrowings     634,524    
Repayment of loans and borrowings (50,137)   (1,296,032)   € (52,782)
Interest (paid)/received (50,521)   (90,765)    
Payment of capitalized transaction cost (250)   (3,955)    
Total increase (decrease) in liabilities arising from financing activities (100,908)   (756,228)    
The effect of changes in foreign exchange rates (6,946)   (14,668)    
Interest expense (income) 58,942   86,215    
Amortization of capitalized transaction cost (830)   26,528    
Capitalized transaction cost not yet paid 250   (250)    
Ending balance 1,145,143   1,194,635   1,853,038
Original EUR Term Loan          
Disclosure of reconciliation of liabilities arising from financing activities [line items]          
Beginning balance     379,197    
Changes from financing cash flows          
Repayment of loans and borrowings     (375,000)    
Interest (paid)/received     (26,140)    
Total increase (decrease) in liabilities arising from financing activities     (401,140)    
Interest expense (income)     21,943    
Ending balance         379,197
EUR Term Loan          
Disclosure of reconciliation of liabilities arising from financing activities [line items]          
Beginning balance 378,591        
Changes from financing cash flows          
Proceeds from loans and borrowings     375,000    
Interest (paid)/received (18,097)        
Total increase (decrease) in liabilities arising from financing activities (18,097)   375,000    
Interest expense (income) 16,748   3,591    
Ending balance 377,242   378,591    
Original USD Term Loan          
Disclosure of reconciliation of liabilities arising from financing activities [line items]          
Beginning balance | $       $ 748,444  
Changes from financing cash flows          
Repayment of loans and borrowings | $       (730,836)  
Interest (paid)/received | $       (37,391)  
Total increase (decrease) in liabilities arising from financing activities | $       (768,227)  
The effect of changes in foreign exchange rates | $       (6,573)  
Interest expense (income) | $       26,356  
Ending balance | $          
USD Term Loan          
Disclosure of reconciliation of liabilities arising from financing activities [line items]          
Beginning balance | $   $ 160,773      
Changes from financing cash flows          
Proceeds from loans and borrowings | $       259,524  
Repayment of loans and borrowings | $   (50,137)   (90,196)  
Interest (paid)/received | $   (9,928)   (2,689)  
Total increase (decrease) in liabilities arising from financing activities | $   (60,065)   166,639  
The effect of changes in foreign exchange rates | $   (6,977)   (8,573)  
Interest expense (income) | $   10,428   2,707  
Ending balance | $   $ 104,159   $ 160,773  
Vendor Loan          
Disclosure of reconciliation of liabilities arising from financing activities [line items]          
Beginning balance 212,121   305,048    
Changes from financing cash flows          
Repayment of loans and borrowings     (100,000)    
Interest (paid)/received     (2,049)    
Total increase (decrease) in liabilities arising from financing activities     (102,049)    
Interest expense (income) 9,270   9,122    
Ending balance 221,391   212,121   305,048
Senior Notes          
Disclosure of reconciliation of liabilities arising from financing activities [line items]          
Beginning balance 437,873   437,873    
Changes from financing cash flows          
Interest (paid)/received (22,496)   (22,496)    
Total increase (decrease) in liabilities arising from financing activities (22,496)   (22,496)    
Interest expense (income) 22,496   22,496    
Ending balance 437,873   437,873   437,873
Amortized Transaction Costs of Loans and Borrowings          
Disclosure of reconciliation of liabilities arising from financing activities [line items]          
Beginning balance 5,277   (17,524)    
Changes from financing cash flows          
Payment of capitalized transaction cost (250)   (3,955)    
Total increase (decrease) in liabilities arising from financing activities (250)   (3,955)    
The effect of changes in foreign exchange rates 31   478    
Amortization of capitalized transaction cost (830)   26,528    
Capitalized transaction cost not yet paid 250   (250)    
Ending balance 4,478   5,277   (17,524)
Amortized Transaction Costs of RCF          
Disclosure of reconciliation of liabilities arising from financing activities [line items]          
Beginning balance (1,453)   (1,826)    
Changes from financing cash flows          
Payment of capitalized transaction cost     (1,508)    
Total increase (decrease) in liabilities arising from financing activities     (1,508)    
Amortization of capitalized transaction cost 329   1,881    
Ending balance (1,124)   (1,453)   (1,826)
Interest Cap          
Disclosure of reconciliation of liabilities arising from financing activities [line items]          
Beginning balance (146)   (2,913)    
Changes from financing cash flows          
Interest (paid)/received 144   1,359    
Total increase (decrease) in liabilities arising from financing activities 144   1,359    
Changes in fair value 146   2,767    
Interest expense (income) (144)   (1,359)    
Ending balance € (0)   € (146)   € (2,913)