Segment Reporting - Segment Reporting (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Segment Reporting Information [Line Items]
Net sales	$ 362.4	$ 358.1	$ 750.7	$ 718.8
Gross profit/(loss)	111.1	102.8	228.9	207.3
Operating income/(loss)	31.7	28.3	67.9	57.2
Operating Segments [Member] \| Fuel Specialties [Member]
Segment Reporting Information [Line Items]
Net sales	133.3	134.2	289.3	277.6
Gross profit/(loss)	44.7	44.5	100.4	93.0
Operating income/(loss)	24.1	23.7	57.0	51.9
Operating Segments [Member] \| Fuel Specialties [Member] \| Refinery and Performance [Member]
Segment Reporting Information [Line Items]
Net sales	95.2	98.1	212.5	209.1
Operating Segments [Member] \| Fuel Specialties [Member] \| Other [Member]
Segment Reporting Information [Line Items]
Net sales	38.1	36.1	76.8	68.5
Operating Segments [Member] \| Performance Chemicals [Member]
Segment Reporting Information [Line Items]
Net sales	104.7	118.9	222.8	242.9
Gross profit/(loss)	24.0	23.8	50.6	49.2
Operating income/(loss)	11.0	9.7	24.5	21.8
Operating Segments [Member] \| Performance Chemicals [Member] \| Personal Care [Member]
Segment Reporting Information [Line Items]
Net sales	54.9	62.6	115.9	123.0
Operating Segments [Member] \| Performance Chemicals [Member] \| Home Care [Member]
Segment Reporting Information [Line Items]
Net sales	23.1	26.5	50.1	56.2
Operating Segments [Member] \| Performance Chemicals [Member] \| Other [Member]
Segment Reporting Information [Line Items]
Net sales	26.7	29.8	56.8	63.7
Operating Segments [Member] \| Oilfield Services [Member]
Segment Reporting Information [Line Items]
Net sales	122.5	95.0	236.7	187.9
Gross profit/(loss)	41.5	28.6	79.2	60.0
Operating income/(loss)	10.1	4.1	17.9	7.1
Operating Segments [Member] \| Octane Additives [Member]
Segment Reporting Information [Line Items]
Net sales	1.9	10.0	1.9	10.4
Gross profit/(loss)	0.9	5.9	(1.3)	5.1
Operating income/(loss)	0.1	5.2	(2.7)	3.8
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Corporate costs	$ (13.6)	$ (14.4)	$ (28.8)	$ (27.4)

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