Segments, Concentrations and Geographic Information - Net Sales to Third Parties by Geographic Region (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 482.8	$ 240.4
North America (primarily U.S.) [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	273.0	125.7
Europe Excluding Germany [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	81.7	44.2
Germany [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	62.2	49.3
Asia And Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 65.9	$ 21.2