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Pension and Post-Employment Benefits - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Retirement age of service		65 years
Annual cash contribution		$ 1.0
Percentage change in discount rate		0.25%
Amount change in PBO due to discount rate		$ 21.0
Amount change in net pension credit due to discount rate		0.5
Amount change in PBO due to change price inflation		$ 14.0
Percentage change in price inflation		0.25%
Amount change in net pension credit due price inflation		$ 0.6
Maximum percentage of Plan's assets invested in individual company's investment funds		5.00%
Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Net pension credit, total	$ 6.7
United Kingdom Government Gilts [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of asset allocation, actual		9.00%	10.00%
Debt Security [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset allocation		85.00%
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset allocation		15.00%
German Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Net service cost, total		$ 0.2	$ 0.2
Net pension credit, total		0.6	0.6	$ 0.4
Amount of unrecognized actuarial net losses, net of tax		2.1
Amount tax on unrecognized actuarial net losses		0.7
Other Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Amount of contributions to defined contribution schemes		$ 8.6	$ 7.9
United Kingdom Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of asset allocation, actual		100.00%	100.00%	100.00%
United Kingdom Plan [Member] | Index-Tracking Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of asset allocation, actual		0.00%	30.00%
United Kingdom Plan [Member] | Debt Security [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of asset allocation, actual		83.00%	53.00%	66.00%
United Kingdom Plan [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of asset allocation, actual		12.00%	38.00%	25.00%
Germany [Member]
Defined Benefit Plan Disclosure [Line Items]
Net service cost, total		$ 0.2	$ 0.2	$ 0.2
Europe [Member] | Performance Chemicals [Member]
Defined Benefit Plan Disclosure [Line Items]
Post-employment obligations European businesses		4.4	4.7
Selling, General and Administrative Expenses [Member]
Defined Benefit Plan Disclosure [Line Items]
Net service cost, total		$ 1.2	$ 0.9	$ 1.0
Selling, General and Administrative Expenses [Member] | Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Net service cost, total	$ 0.9

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