Financial Instruments - Notional Amount and Estimated Fair Value of Derivative Contracts and Related Classification (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Foreign currency contracts
Derivatives, Fair Value [Line Items]
Total fair value	$ 14.3	$ (22.8)
Total notional amount	2,153.0	2,219.6
Foreign currency contracts \| Designated as hedging instrument \| Cash flow hedging
Derivatives, Fair Value [Line Items]
Other current assets	20.6	16.9
Other long-term assets	2.8	1.3
Other current liabilities	(8.4)	(28.4)
Other long-term liabilities	(2.0)	(8.0)
Total fair value	13.0	(18.2)
Total notional amount	$ 1,499.0	$ 1,538.5
Foreign currency contracts \| Designated as hedging instrument \| Cash flow hedging \| Maximum
Derivatives, Fair Value [Line Items]
Outstanding maturities in months, not to exceed	24 months	24 months
Foreign currency contracts \| Not designated as hedging instrument
Derivatives, Fair Value [Line Items]
Other current assets	$ 6.1	$ 1.8
Other current liabilities	(4.8)	(6.4)
Total fair value	1.3	(4.6)
Total notional amount	$ 654.0	$ 681.1
Foreign currency contracts \| Not designated as hedging instrument \| Maximum
Derivatives, Fair Value [Line Items]
Outstanding maturities in months, not to exceed	12 months	12 months
Interest rate swap \| Designated as hedging instrument \| Cash flow hedging
Derivatives, Fair Value [Line Items]
Other current liabilities	$ (14.7)
Total notional amount	$ 500.0
Interest rate swap \| Designated as hedging instrument \| Cash flow hedging \| Maximum
Derivatives, Fair Value [Line Items]
Outstanding maturities in months, not to exceed	3 months

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled within one year or normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

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- Definition

Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

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- Definition

Period remaining until the derivative contract matures, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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