Basis of Presentation and Summary of Significant Accounting Policies - Property, Plant and Equipment by Geographic Location (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property, plant and equipment, net	$ 301,200,000	$ 283,200,000
Impairment of Intangible Assets (Excluding Goodwill)	0	0	$ 0
Impairment of long-lived assets	0	0	0
Impairment of long-lived assets	0	0	$ 0
U.S.
Property, Plant and Equipment [Line Items]
Property, plant and equipment, net	183,600,000	172,300,000
Western Europe
Property, Plant and Equipment [Line Items]
Property, plant and equipment, net	76,700,000	69,700,000
Developing
Property, Plant and Equipment [Line Items]
Property, plant and equipment, net	30,400,000	31,100,000
Other Developed
Property, Plant and Equipment [Line Items]
Property, plant and equipment, net	$ 10,500,000	$ 10,100,000