Acquired Intangible Assets and Related Amortization (Detail) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Finite Lived Intangible Assets [Line Items]
Acquired intangible assets, net	$ 307.8	$ 299.1
Customer Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Acquired intangible assets, gross	313.9	298.4
Accumulated amortization	(121.9)	(110.0)
Acquired intangible assets, net	192.0	188.4
Trade Secrets [Member]
Finite Lived Intangible Assets [Line Items]
Acquired intangible assets, gross	30.0	29.7
Accumulated amortization	(25.0)	(23.1)
Acquired intangible assets, net	5.0	6.6
Computer Software Intangible Asset [Member]
Finite Lived Intangible Assets [Line Items]
Acquired intangible assets, gross	91.3	74.7
Accumulated amortization	(55.3)	(47.7)
Acquired intangible assets, net	36.0	27.0
Trade Names [Member]
Finite Lived Intangible Assets [Line Items]
Acquired intangible assets, gross	75.3	72.4
Accumulated amortization	(19.0)	(16.2)
Acquired intangible assets, net	56.3	56.2
Other Intangible Assets [Member]
Finite Lived Intangible Assets [Line Items]
Acquired intangible assets, gross	43.5	44.3
Accumulated amortization	(25.0)	(23.4)
Acquired intangible assets, net	$ 18.5	$ 20.9