v3.26.3
Accumulated Other Comprehensive Loss - Changes in accumulated other comprehensive loss (Details) - USD ($)
$ in Millions
 9 Months Ended
Sep. 30, 2026
Jun. 30, 2026
Mar. 31, 2026
Dec. 31, 2025
Sep. 30, 2025
Jun. 30, 2025
Mar. 31, 2025
Dec. 31, 2024
Accumulated Other Comprehensive Income (Loss) [Line Items]                
Equity, Including Portion Attributable to Noncontrolling Interest $ 1,130.8 $ 1,145.7 $ 1,145.7 $ 1,145.3 $ 1,250.4 $ 1,257.8 $ 1,299.7 $ 1,307.2
Changes in accumulated other comprehensive loss                
Other comprehensive income (loss), net of tax, before reclassifications 27.5              
Amounts reclassified from AOCI, net of tax expense of $—, $1.7, $—, and $1.7 (5.8)              
Reclassification from AOCI, Current Period, Tax 1.7              
Other comprehensive income (loss) 21.7              
Accumulated Foreign Currency Adjustment Attributable to Parent                
Accumulated Other Comprehensive Income (Loss) [Line Items]                
Equity, Including Portion Attributable to Noncontrolling Interest (0.6)     0.0        
Changes in accumulated other comprehensive loss                
Other comprehensive income (loss), net of tax, before reclassifications (0.6)              
Amounts reclassified from AOCI, net of tax expense of $—, $1.7, $—, and $1.7 0.0              
Reclassification from AOCI, Current Period, Tax 0.0              
Other comprehensive income (loss) (0.6)              
Unrealized gains/(losses) on derivative financial instruments                
Accumulated Other Comprehensive Income (Loss) [Line Items]                
Equity, Including Portion Attributable to Noncontrolling Interest 19.4     (2.8)        
Changes in accumulated other comprehensive loss                
Other comprehensive income (loss), net of tax, before reclassifications 28.1              
Amounts reclassified from AOCI, net of tax expense of $—, $1.7, $—, and $1.7 (5.9)              
Reclassification from AOCI, Current Period, Tax 1.7              
Other comprehensive income (loss) 22.2              
Net actuarial gains/(losses) of defined benefit plans                
Accumulated Other Comprehensive Income (Loss) [Line Items]                
Equity, Including Portion Attributable to Noncontrolling Interest (1.3)     (1.4)        
Changes in accumulated other comprehensive loss                
Other comprehensive income (loss), net of tax, before reclassifications 0.0              
Amounts reclassified from AOCI, net of tax expense of $—, $1.7, $—, and $1.7 0.1              
Reclassification from AOCI, Current Period, Tax 0.0              
Other comprehensive income (loss) 0.1              
Accumulated other comprehensive income (loss)                
Accumulated Other Comprehensive Income (Loss) [Line Items]                
Equity, Including Portion Attributable to Noncontrolling Interest $ 17.5 $ 8.0 $ 1.0 $ (4.2) $ (3.9) $ (4.2) $ (4.2) $ (4.2)