Goodwill and Other Identifiable Intangible Assets - Detail of Identifiable Intangible Assets (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Acquired Intangible Assets By Major Class [Line Items]
Cost	$ 510.5	$ 433.7
Accumulated amortization	(323.3)	(316.7)
Net	187.2	117.0
Net, indefinite-life intangibles	174.3	159.3
Cost	684.8	593.0
Net	361.5	276.3
Customer relationships
Acquired Intangible Assets By Major Class [Line Items]
Cost	424.6	347.1
Accumulated amortization	(253.3)	(247.9)
Net	171.3	99.2
Trade names intangibles
Acquired Intangible Assets By Major Class [Line Items]
Cost	0.4	0.4
Accumulated amortization	(0.4)	(0.4)
Net	0.0	0.0
Patented Technology [Member]
Acquired Intangible Assets By Major Class [Line Items]
Cost	85.5	86.2
Accumulated amortization	(69.6)	(68.4)
Net	$ 15.9	$ 17.8