Segments, Concentrations and Geographic Information - Net Sales to Third Parties by Geographic Region (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 466.5	$ 237.3	$ 949.3	$ 477.7
North America (primarily U.S.) [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	269.8	119.0	542.8	244.7
Europe Excluding Germany [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	79.9	42.5	161.7	86.6
Germany [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	56.8	48.8	119.0	98.2
Asia And Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 60.0	$ 27.0	$ 125.8	$ 48.2