Acquired Intangible Assets and Related Amortization (Detail) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Finite Lived Intangible Assets [Line Items]
Acquired intangible assets, net	$ 287.1	$ 296.4
Customer Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Acquired intangible assets, gross	317.2	310.1
Accumulated amortization	(133.5)	(124.4)
Acquired intangible assets, net	183.7	185.7
Trade Secrets [Member]
Finite Lived Intangible Assets [Line Items]
Acquired intangible assets, gross	30.0	29.9
Accumulated amortization	(26.9)	(25.6)
Acquired intangible assets, net	3.1	4.3
Computer Software Intangible Asset [Member]
Finite Lived Intangible Assets [Line Items]
Acquired intangible assets, gross	91.7	87.7
Accumulated amortization	(63.2)	(54.9)
Acquired intangible assets, net	28.5	32.8
Trade Names [Member]
Finite Lived Intangible Assets [Line Items]
Acquired intangible assets, gross	76.9	75.3
Accumulated amortization	(22.4)	(19.9)
Acquired intangible assets, net	54.5	55.4
Other Intangible Assets [Member]
Finite Lived Intangible Assets [Line Items]
Acquired intangible assets, gross	44.2	43.5
Accumulated amortization	(26.9)	(25.3)
Acquired intangible assets, net	$ 17.3	$ 18.2