Segment Reporting and Geographical Area Data - Segment Reporting (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Net sales	$ 1,306.8	$ 883.4	$ 1,012.3
Gross profit	403.3	332.3	346.0
Adjustment to fair value of contingent consideration	0.0	9.4	40.7
(Loss)/profit on disposal of subsidiary	(0.9)	(1.4)	1.6
Foreign exchange loss on liquidation of subsidiary	(1.8)	0.0	0.0
Operating income	129.7	105.4	156.3
Identifiable assets at year end	1,410.2	1,181.4	1,028.6
Operating Segments [Member] \| Fuel Specialties [Member]
Segment Reporting Information [Line Items]
Net sales	523.8	509.6	532.8
Gross profit	188.2	186.4	176.0
Operating income	107.1	110.6	102.1
Identifiable assets at year end	437.0	397.2	408.9
Operating Segments [Member] \| Fuel Specialties [Member] \| Refinery and Performance [Member]
Segment Reporting Information [Line Items]
Net sales	397.0	388.9	408.0
Operating Segments [Member] \| Fuel Specialties [Member] \| Other [Member]
Segment Reporting Information [Line Items]
Net sales	126.8	120.7	124.8
Operating Segments [Member] \| Performance Chemicals [Member]
Segment Reporting Information [Line Items]
Net sales	419.5	138.7	155.0
Gross profit	75.8	43.4	42.4
Operating income	32.6	16.0	16.3
Identifiable assets at year end	480.8	340.0	120.2
Operating Segments [Member] \| Performance Chemicals [Member] \| Personal Care [Member]
Segment Reporting Information [Line Items]
Net sales	200.0	126.8	119.6
Operating Segments [Member] \| Performance Chemicals [Member] \| Home Care [Member]
Segment Reporting Information [Line Items]
Net sales	121.1	2.0	0.0
Operating Segments [Member] \| Performance Chemicals [Member] \| Fragrances [Member]
Segment Reporting Information [Line Items]
Net sales	0.0	0.0	23.0
Operating Segments [Member] \| Performance Chemicals [Member] \| Other [Member]
Segment Reporting Information [Line Items]
Net sales	98.4	9.9	12.4
Operating Segments [Member] \| Oilfield Services [Member]
Segment Reporting Information [Line Items]
Net sales	304.4	191.7	265.0
Gross profit	109.3	76.4	99.1
Operating income	9.5	(4.7)	9.0
Identifiable assets at year end	256.6	240.0	240.9
Operating Segments [Member] \| Octane Additives [Member]
Segment Reporting Information [Line Items]
Net sales	59.1	43.4	59.5
Gross profit	30.0	26.1	28.5
Operating income	26.7	22.7	24.7
Identifiable assets at year end	41.7	38.1	28.7
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Pension credit	4.4	6.7	0.2
Corporate costs	(47.9)	(53.9)	(38.3)
Identifiable assets at year end	194.1	166.1	229.9
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
(Loss)/profit on disposal of subsidiary	$ (0.9)	$ (1.4)	$ 1.6

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