v3.26.1
Segment reporting - Summary of Reconciliation of Adjusted Segment EBITDA to Net income (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Adjusted Segment EBITDA Reconciliation [Line Items]        
Interest expense and related financing costs - net $ (52.9) $ (21.5) $ (123.7) $ (50.1)
Income tax expense (12.8) (18.1) (17.3) (30.1)
Net income (loss) (16.9) 62.4 (25.9) 97.4
Adjusted Segment EBITDA to Net Income [Member]        
Adjusted Segment EBITDA Reconciliation [Line Items]        
Total Adjusted Segment EBITDA 188.4 152.0 321.3 270.5
Unallocated corporate costs (HQ & other not included in Adjusted Segment EBITDA) (16.1) (7.9) (26.5) (12.4)
Acquisition and Divestment related gains (losses) - net (0.5) (0.7) (0.7) (0.4)
Transaction costs (0.5) 0.0 (4.6) 0.0
Transformation costs (1.8) (3.1) (5.3) (5.7)
IPO and Public market readiness costs (81.2) (0.1) (91.1) (0.1)
Share-based compensation (1.1) 0.0 (1.1) 0.0
Management adjustments (85.1) (3.9) (102.8) (6.2)
Other non-cash items (2.0) (2.1) (5.5) (3.7)
Depreciation and amortization (40.1) (37.0) (78.3) (72.1)
Other income (expense) - net 3.7 0.9 6.9 1.5
Interest expense and related financing costs - net (52.9) (21.5) (123.7) (50.1)
Income tax expense (12.8) (18.1) (17.3) (30.1)
Net income (loss) $ (16.9) $ 62.4 $ (25.9) $ 97.4