Pension and Post-Employment Benefits - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Europe [Member] | Performance Chemicals [Member]
Defined Benefit Plan Disclosure [Line Items]
Post-employment obligations European businesses	$ 4.4		$ 4.4
Germany [Member]
Defined Benefit Plan Disclosure [Line Items]
Net service cost, total	0.0	$ 0.0
Selling, General and Administrative Expenses [Member]
Defined Benefit Plan Disclosure [Line Items]
Net service cost, total	$ 0.2	$ 0.3