Segmental Reporting - Segment Reporting (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Segment Reporting Information [Line Items]
Net sales	$ 242.9	$ 221.3	$ 512.1	$ 442.0
Gross profit	87.5	68.6	169.3	134.3
Operating income	57.4	25.3	80.8	43.3
Pension credit/(charge)	0.1	(0.9)	0.1	(1.7)
Adjustment to fair value of contingent consideration	26.6	0.0	23.1	0.0
Operating Segments [Member] \| Fuel Specialties [Member]
Segment Reporting Information [Line Items]
Net sales	182.3	145.1	381.7	309.3
Gross profit	68.9	43.9	130.4	95.9
Operating income	27.8	17.5	51.3	43.3
Operating Segments [Member] \| Performance Chemicals [Member]
Segment Reporting Information [Line Items]
Net sales	54.1	59.4	111.7	115.5
Gross profit	14.8	15.3	29.3	28.9
Operating income	7.5	7.8	13.9	14.3
Operating Segments [Member] \| Octane Additives [Member]
Segment Reporting Information [Line Items]
Net sales	6.5	16.8	18.7	17.2
Gross profit	3.8	9.4	9.6	9.5
Operating income	2.8	8.3	7.9	7.1
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Pension credit/(charge)	0.1	(0.9)	0.1	(1.7)
Adjustment to fair value of contingent consideration	26.6	0.0	23.1	0.0
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Corporate costs	$ (7.4)	$ (7.4)	$ (15.5)	$ (19.7)

Corporate costs.

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- Definition

Amount of increase (decrease) in the value of a contingent consideration liability, including, but not limited to, differences arising upon settlement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 30

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- Definition

The total amount of net periodic benefit cost for defined benefit plans for the period. Periodic benefit costs include the following components: service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) due to settlements or curtailments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

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- Definition

Aggregate revenue less cost of goods and services sold or operating expenses directly attributable to the revenue generation activity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1,2)

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The net result for the period of deducting operating expenses from operating revenues.

+ References

No definition available.

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- Definition

Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

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-Paragraph 2

-Subparagraph (SX 210.5-03.1)

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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