Summary of Significant Accounting Policies - Summary of Intangible Assets (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 246.3	$ 255.8
Accumulated Amortization	(153.8)	(126.1)
Net Carrying Value	92.5us-gaap_FiniteLivedIntangibleAssetsNet	129.7us-gaap_FiniteLivedIntangibleAssetsNet
Weighted Average Useful Life (years)	8 years 4 months 24 days	8 years 1 month 6 days
Technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	31.4	32.7
Accumulated Amortization	(16.3)	(13.0)
Net Carrying Value	15.1	19.7
Weighted Average Useful Life (years)	9 years	8 years 10 months 24 days
Customer-based
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	214.9	223.1
Accumulated Amortization	(137.5)	(113.1)
Net Carrying Value	$ 77.4	$ 110.0
Weighted Average Useful Life (years)	8 years 2 months 12 days	8 years

Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16323-109275

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Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

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Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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- Definition

Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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