Segment Reporting - Segment Reporting (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Net sales	$ 363.1	$ 332.4	$ 1,081.9	$ 953.0
Gross profit	111.0	98.8	318.3	294.8
Restructuring charge	(4.8)	0.0	(4.8)	0.0
Loss on disposal of subsidiary	0.0	0.0	0.0	(1.0)
Foreign exchange loss on liquidation of subsidiary	0.0	0.0	0.0	(1.8)
Operating income/(loss)	33.4	29.0	90.6	87.8
Operating Segments [Member] \| Fuel Specialties [Member]
Segment Reporting Information [Line Items]
Net sales	134.9	130.1	412.5	377.8
Gross profit	48.8	44.6	141.8	135.9
Operating income/(loss)	28.8	25.1	80.7	76.0
Operating Segments [Member] \| Fuel Specialties [Member] \| Refinery and Performance [Member]
Segment Reporting Information [Line Items]
Net sales	97.8	97.4	306.9	286.5
Operating Segments [Member] \| Fuel Specialties [Member] \| Other [Member]
Segment Reporting Information [Line Items]
Net sales	37.1	32.7	105.6	91.3
Operating Segments [Member] \| Performance Chemicals [Member]
Segment Reporting Information [Line Items]
Net sales	114.8	110.3	357.7	309.7
Gross profit	25.3	20.7	74.5	54.8
Operating income/(loss)	12.4	9.7	34.2	22.2
Operating Segments [Member] \| Performance Chemicals [Member] \| Personal Care [Member]
Segment Reporting Information [Line Items]
Net sales	60.6	52.2	183.6	148.4
Operating Segments [Member] \| Performance Chemicals [Member] \| Home Care [Member]
Segment Reporting Information [Line Items]
Net sales	28.2	32.7	84.5	89.0
Operating Segments [Member] \| Performance Chemicals [Member] \| Other [Member]
Segment Reporting Information [Line Items]
Net sales	26.0	25.4	89.6	72.3
Operating Segments [Member] \| Oilfield Services [Member]
Segment Reporting Information [Line Items]
Net sales	104.2	81.9	292.1	224.5
Gross profit	33.5	28.5	93.5	82.9
Operating income/(loss)	7.0	1.8	14.1	8.5
Operating Segments [Member] \| Octane Additives [Member]
Segment Reporting Information [Line Items]
Net sales	9.2	10.1	19.6	41.0
Gross profit	3.4	5.0	8.5	21.2
Operating income/(loss)	2.7	4.4	6.5	19.2
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Corporate costs	$ (12.7)	$ (12.0)	$ (40.1)	$ (35.3)

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