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Income Taxes - Schedule of Unrecognized Tax Benefit (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Beginning balance	$ 14.9us-gaap_UnrecognizedTaxBenefits	$ 30.4us-gaap_UnrecognizedTaxBenefits	$ 29.7us-gaap_UnrecognizedTaxBenefits
Increases in tax positions for prior years	0.7us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	0.2us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	1.4us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions
Decreases in tax positions for prior years	(0.5)us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	(4.9)us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	(1.0)us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions
Acquisition related:
Purchase Accounting	0.3us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromAcquisition	1.3us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromAcquisition
Increases in tax positions for current year	3.4us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	1.7us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	1.9us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions
Settlements	(1.3)us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities		(0.4)us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities
Lapse in statutes of limitation	(2.6)us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations	(13.8)us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations	(1.2)us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations
Ending balance	$ 14.9us-gaap_UnrecognizedTaxBenefits	$ 14.9us-gaap_UnrecognizedTaxBenefits	$ 30.4us-gaap_UnrecognizedTaxBenefits

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- Definition

Amount of unrecognized tax benefits pertaining to uncertain tax positions taken in tax returns.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Unrecognized Tax Benefit

-URI http://asc.fasb.org/extlink&oid=6527854



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

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-Section 50

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Amount of decrease in unrecognized tax benefits resulting from acquisitions.

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Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

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Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities.

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-Publisher FASB

-Name Accounting Standards Codification

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Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

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Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

+ References

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-Name Accounting Standards Codification

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Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations.

+ References

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-Name Accounting Standards Codification

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