v3.25.2
Accumulated Other Comprehensive Loss - Changes in accumulated other comprehensive loss (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Mar. 31, 2025
Jun. 30, 2024
Mar. 31, 2024
Jun. 30, 2025
Jun. 30, 2024
Dec. 31, 2024
Dec. 31, 2023
Accumulated Other Comprehensive Income (Loss) [Line Items]                
Equity, Including Portion Attributable to Noncontrolling Interest $ 1,257.8 $ 1,299.7 $ 1,304.0 $ 1,288.5 $ 1,257.8 $ 1,304.0 $ 1,307.2 $ 1,275.5
Changes in accumulated other comprehensive loss                
Other comprehensive loss, net of tax, before reclassifications         (1.5)      
Amounts reclassified from AOCI, net of tax benefit of $0.5, $—, and $0.5         1.7      
Reclassification from AOCI, Current Period, Tax         0.5      
Less: noncontrolling interest (0.1) (0.1) 10.9 (7.5) (0.2) 3.4    
Other comprehensive income (loss)         0.0      
Unrealized gains/(losses) on derivative financial instruments                
Accumulated Other Comprehensive Income (Loss) [Line Items]                
Equity, Including Portion Attributable to Noncontrolling Interest (3.0)       (3.0)   (3.0)  
Changes in accumulated other comprehensive loss                
Other comprehensive loss, net of tax, before reclassifications         (1.5)      
Amounts reclassified from AOCI, net of tax benefit of $0.5, $—, and $0.5         1.7      
Reclassification from AOCI, Current Period, Tax         0.5      
Other comprehensive income (loss)         0.0      
Net actuarial gains/(losses) of defined benefit plans                
Accumulated Other Comprehensive Income (Loss) [Line Items]                
Equity, Including Portion Attributable to Noncontrolling Interest (1.2)       (1.2)   (1.2)  
Changes in accumulated other comprehensive loss                
Other comprehensive loss, net of tax, before reclassifications         0.0      
Amounts reclassified from AOCI, net of tax benefit of $0.5, $—, and $0.5         0.0      
Reclassification from AOCI, Current Period, Tax         0.0      
Other comprehensive income (loss)         0.0      
Accumulated Gain (Loss), Net, Cash Flow Hedge, Noncontrolling Interest [Member]                
Changes in accumulated other comprehensive loss                
Less: noncontrolling interest         (0.2)      
Noncontrolling Interest [Member]                
Accumulated Other Comprehensive Income (Loss) [Line Items]                
Equity, Including Portion Attributable to Noncontrolling Interest 248.7 246.5 238.5 239.2 248.7 238.5 248.3 238.4
Changes in accumulated other comprehensive loss                
Less: noncontrolling interest (0.1) (0.1) (0.1) (0.1) (0.2)      
Accumulated other comprehensive income (loss)                
Accumulated Other Comprehensive Income (Loss) [Line Items]                
Equity, Including Portion Attributable to Noncontrolling Interest (4.2) (4.2) 7.4 18.4 $ (4.2) $ 7.4 $ (4.2) $ 11.0
Changes in accumulated other comprehensive loss                
Less: noncontrolling interest $ 0.0 $ 0.0 $ 11.0 $ (7.4)