v3.26.1
Intangible assets - Schedule of Finite-Lived Intangible Assets (Details) - USD ($)
$ in Thousands
Sep. 30, 2025
Jun. 30, 2025
Mar. 31, 2025
Sep. 30, 2024
Jun. 30, 2024
Mar. 31, 2024
Sep. 30, 2023
Jun. 30, 2023
Mar. 31, 2023
Finite-Lived Intangible Assets [Line Items]                  
Total cost $ 5,206,920                
Accumulated amortization (1,822,598)                
Impairment (86,739)                
 Net book value 3,297,583 $ 3,443,096 $ 3,501,307 $ 3,605,814 $ 3,632,354 $ 3,748,939 $ 3,934,673 $ 4,049,793 $ 4,164,410
Adjustments                  
Finite-Lived Intangible Assets [Line Items]                  
 Net book value (86,739) $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0
Customer relationships                  
Finite-Lived Intangible Assets [Line Items]                  
Total cost 4,134,107                
Order backlog                  
Finite-Lived Intangible Assets [Line Items]                  
Total cost 545,922                
Trade names & brands                  
Finite-Lived Intangible Assets [Line Items]                  
Total cost 204,713                
Patient database                  
Finite-Lived Intangible Assets [Line Items]                  
Total cost 170,487                
Technology assets                  
Finite-Lived Intangible Assets [Line Items]                  
Total cost $ 151,691