v3.26.1
Segment Reporting - Segment Reporting (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Segment Reporting Information [Line Items]        
Net sales $ 491.4 $ 439.7 $ 944.6 $ 880.5
Gross profit 138.3 123.2 261.8 248.3
Adjustment to fair value of contingent consideration (0.1) (0.8) 4.6 (1.5)
Profit on disposal of property, plant and equipment 0.0 0.1 0.0 0.2
Operating income/(loss) 39.7 34.3 76.2 76.8
Operating Segments [Member]        
Segment Reporting Information [Line Items]        
Adjustment to fair value of contingent consideration (0.1) (0.8) 4.6 (1.5)
Profit on disposal of property, plant and equipment 0.0 0.1 0.0 0.2
Operating Segments [Member] | Performance Chemicals [Member]        
Segment Reporting Information [Line Items]        
Net sales 190.3 173.8 359.7 342.2
Gross profit 33.0 30.5 61.4 65.8
Operating income/(loss) 16.4 14.3 27.1 34.1
Operating Segments [Member] | Fuel Specialties [Member]        
Segment Reporting Information [Line Items]        
Net sales 185.7 165.1 367.3 335.4
Gross profit 68.0 62.9 132.3 123.7
Operating income/(loss) 36.3 35.4 74.1 72.3
Operating Segments [Member] | Oilfield Services [Member]        
Segment Reporting Information [Line Items]        
Net sales 115.4 100.8 217.6 202.9
Gross profit 37.3 29.8 68.1 58.8
Operating income/(loss) 8.7 6.2 14.3 10.3
Operating Segments [Member] | Personal Care [Member] | Performance Chemicals [Member]        
Segment Reporting Information [Line Items]        
Net sales 111.9 105.0 209.1 205.5
Operating Segments [Member] | Home Care [Member] | Performance Chemicals [Member]        
Segment Reporting Information [Line Items]        
Net sales 31.7 26.1 62.5 52.4
Operating Segments [Member] | Other [Member] | Performance Chemicals [Member]        
Segment Reporting Information [Line Items]        
Net sales 46.7 42.7 88.1 84.3
Operating Segments [Member] | Refinery and Performance [Member] | Fuel Specialties [Member]        
Segment Reporting Information [Line Items]        
Net sales 127.3 112.8 258.2 242.2
Operating Segments [Member] | Other [Member] | Fuel Specialties [Member]        
Segment Reporting Information [Line Items]        
Net sales 58.4 52.3 109.1 93.2
Corporate, Non-Segment [Member]        
Segment Reporting Information [Line Items]        
Corporate costs $ (21.6) $ (20.9) $ (43.9) $ (38.6)