Goodwill and Other Identifiable Intangible Assets - Detail of Identifiable Intangible Assets (Detail) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Acquired Intangible Assets By Major Class [Line Items]
Cost	$ 458.7	$ 433.7
Accumulated amortization	(289.6)	(316.7)
Net	169.1	117.0
Net, indefinite-life intangibles	172.3	159.3
Cost	631.0	593.0
Net	341.4	276.3
Customer relationships
Acquired Intangible Assets By Major Class [Line Items]
Cost	415.9	347.1
Accumulated amortization	(260.8)	(247.9)
Net	155.1	99.2
Trade names intangibles
Acquired Intangible Assets By Major Class [Line Items]
Cost	0.0	0.4
Accumulated amortization	0.0	(0.4)
Net	0.0	0.0
Patented Technology [Member]
Acquired Intangible Assets By Major Class [Line Items]
Cost	42.8	86.2
Accumulated amortization	(28.8)	(68.4)
Net	$ 14.0	$ 17.8