Goodwill and Other Identifiable Intangible Assets - Detail of Identifiable Intangible Assets (Detail) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Acquired Intangible Assets By Major Class [Line Items]
Cost	$ 452.0	$ 460.4
Accumulated amortization	(297.1)	(294.6)
Net	154.9	165.8
Net, indefinite-life intangibles	171.6	173.4
Cost	623.6	633.8
Net	326.5	339.2
Customer relationships
Acquired Intangible Assets By Major Class [Line Items]
Cost	410.3	418.1
Accumulated amortization	(271.4)	(269.1)
Net	138.9	149.0
Patented Technology [Member]
Acquired Intangible Assets By Major Class [Line Items]
Cost	41.7	42.3
Accumulated amortization	(25.7)	(25.5)
Net	$ 16.0	$ 16.8