Derivative Instruments and Hedging Activities - Balance Sheet Location (Details) - Foreign currency forward contracts - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Designated derivatives: \| Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Asset Derivatives	$ 2.1	$ 4.1
Designated derivatives: \| Accrued liabilities
Derivatives, Fair Value [Line Items]
Liability Derivatives	5.0	1.4
Non-designated derivatives: \| Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Asset Derivatives	0.6	2.2
Non-designated derivatives: \| Accrued liabilities
Derivatives, Fair Value [Line Items]
Liability Derivatives	$ 4.1	$ 2.4

Fair value, after offset of derivative asset, of financial liability or 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, elected not to be and before offset against a right to receive collateral under a master netting arrangement. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=d3e41678-113959

Reference 2: 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

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226006-175313

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226008-175313

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Balance Type:	credit
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