v3.25.2
Fair value of financial instruments - Fixed Rate Debt (Details) - USD ($)
$ in Millions
Jun. 30, 2025
Dec. 31, 2024
2027 Senior Unsecured Notes    
Debt Instrument [Line Items]    
Carrying value $ 600.0 $ 600.0
2027 Senior Unsecured Notes | Level 3    
Debt Instrument [Line Items]    
Fair value 570.2 558.7
2029 Senior Unsecured Notes    
Debt Instrument [Line Items]    
Carrying value 400.0 400.0
2029 Senior Unsecured Notes | Level 3    
Debt Instrument [Line Items]    
Fair value 409.8 399.0
2032 Senior Unsecured Notes    
Debt Instrument [Line Items]    
Carrying value 400.0 400.0
2032 Senior Unsecured Notes | Level 3    
Debt Instrument [Line Items]    
Fair value $ 412.4 $ 397.2