Segmental Reporting - Segmental Reporting (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Segmental reporting
Net sales	$ 185.0	$ 178.5	$ 384.4	$ 379.3
Gross profit	59.4	56.7	123.2	120.7
Operating income	22.3	24.1	44.5	55.3
Pension credit/(charge)	(0.7)	0.1	(1.4)	0.2
Restructuring charge	0	0	0	(0.1)
Impairment of Octane Additives segment goodwill	(0.3)	(0.3)	(0.6)	(0.6)
Operating Segments [Member] | Fuel Specialties [Member]
Segmental reporting
Net sales	126.2	114.5	266.2	245.2
Gross profit	40.5	34.7	87.5	73.4
Operating income	19.2	16.9	44.1	38.6
Operating Segments [Member] | Performance Chemicals [Member]
Segmental reporting
Net sales	44.5	44.9	92.3	91.4
Gross profit	11.3	12.1	21.8	23.2
Operating income	6.5	7.2	11.5	13.2
Operating Segments [Member] | Octane Additives [Member]
Segmental reporting
Net sales	14.3	19.1	25.9	42.7
Gross profit	7.6	9.9	13.9	24.1
Operating income	6.1	8.0	10.9	20.4
Segment Reconciling Items [Member]
Segmental reporting
Pension credit/(charge)	(0.7)	0.1	(1.4)	0.2
Restructuring charge	0	0	0	(0.1)
Impairment of Octane Additives segment goodwill	(0.3)	(0.3)	(0.6)	(0.6)
Corporate, Non-Segment [Member]
Segmental reporting
Corporate costs	$ (8.5)	$ (7.8)	$ (20.0)	$ (16.4)