Segment Reporting - Summary of Segment Depreciation and Amortization (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Summary of segment depreciation and amortization
Depreciation	$ 5.8	$ 5.2
Amortization	6.7	6.9
Operating Segments [Member] | Fuel Specialties [Member]
Summary of segment depreciation and amortization
Depreciation	1.0	1.0
Amortization	0.0	0.2
Operating Segments [Member] | Performance Chemicals [Member]
Summary of segment depreciation and amortization
Depreciation	2.7	2.2
Amortization	2.3	1.9
Operating Segments [Member] | Oilfield Services [Member]
Summary of segment depreciation and amortization
Depreciation	1.5	1.6
Amortization	2.6	3.0
Operating Segments [Member] | Octane Additives [Member]
Summary of segment depreciation and amortization
Depreciation	0.3	0.2
Corporate, Non-Segment [Member]
Summary of segment depreciation and amortization
Depreciation	0.3	0.2
Amortization	$ 1.8	$ 1.8