XML 84 R67.htm IDEA: XBRL DOCUMENT v3.25.4
Goodwill - Summary of Goodwill (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Goodwill [Line Items]    
Gross cost, beginning balance $ 382.5 $ 399.3
Accumulated impairment losses, beginning balance 0.0 0.0
Net book amount, beginning balance 382.5 399.3
Additions 2.0  
Adjustment to the acquired fair values   (3.1)
Exchange effect 14.5 (13.7)
Gross cost, ending balance 399.0 382.5
Accumulated impairment losses, ending balance 0.0 0.0
Net book amount, ending balance 399.0 382.5
Performance Chemicals [Member]    
Goodwill [Line Items]    
Gross cost, beginning balance 130.1 146.9
Accumulated impairment losses, beginning balance 0.0 0.0
Net book amount, beginning balance 130.1 146.9
Additions 0.0  
Adjustment to the acquired fair values   (3.1)
Exchange effect 14.4 (13.7)
Gross cost, ending balance 144.5 130.1
Accumulated impairment losses, ending balance 0.0 0.0
Net book amount, ending balance 144.5 130.1
Fuel Specialties [Member]    
Goodwill [Line Items]    
Gross cost, beginning balance 207.5 207.6
Accumulated impairment losses, beginning balance 0.0 0.0
Net book amount, beginning balance 207.5 207.6
Additions 0.0  
Adjustment to the acquired fair values   0.0
Exchange effect 0.2 (0.1)
Gross cost, ending balance 207.7 207.5
Accumulated impairment losses, ending balance 0.0 0.0
Net book amount, ending balance 207.7 207.5
Oilfield Services [Member]    
Goodwill [Line Items]    
Gross cost, beginning balance 44.9 44.8
Accumulated impairment losses, beginning balance 0.0 0.0
Net book amount, beginning balance 44.9 44.8
Additions 2.0  
Adjustment to the acquired fair values   0.0
Exchange effect (0.1) 0.1
Gross cost, ending balance 46.8 44.9
Accumulated impairment losses, ending balance 0.0 0.0
Net book amount, ending balance $ 46.8 $ 44.9