Subsequent Events - Narrative (Details) $ in Millions		6 Months Ended
Aug. 01, 2018 USD ($)	Jun. 30, 2018 USD ($) $ / €
Subsequent Event [Line Items]
Exchange rate \| $ / €		1.17
Subsequent Event
Subsequent Event [Line Items]
Lease termination	$ 8.0
Pro Forma \| French Business \| Disposal Group, Disposed of by Sale, Not Discontinued Operations
Subsequent Event [Line Items]
Disposal group, enterprise value		$ 246.0
Disposal group, equity value		270.0
Pro Forma \| French Business \| Disposal Group, Disposed of by Sale, Not Discontinued Operations \| Minimum
Subsequent Event [Line Items]
Transaction and exit costs		6.0
Tax expense		18.0
Disposal group, gain		182.0
Total cash available to US Shareholders tax-effected		238.0
Pro Forma \| French Business \| Disposal Group, Disposed of by Sale, Not Discontinued Operations \| Maximum
Subsequent Event [Line Items]
Transaction and exit costs		7.0
Disposal group, costs related to acceleration of vesting of employee restricted stock		1.2
Tax expense		24.0
Disposal group, gain		188.0
Total cash available to US Shareholders tax-effected		$ 245.0

Disposal Group, Including Discontinued Operation, Enterprise Value

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- Definition

Disposal Group, Including Discontinued Operation, Equity Value

+ References

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Disposal Group, Including Discontinued Operation, Tax Expense

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- Definition

Disposal Group, Including Discontinued Operation, Transaction And Exit Costs

+ References

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- Definition

Disposal Group, Including Discontinued Operation, Transaction And Exit Costs Related To Accelerated Vesting Of Employee Restricted Stock

+ References

No definition available.

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- Definition

Amount before tax of gain (loss) recognized on the sale or disposal of a disposal group. Excludes discontinued operations.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=109226348&loc=d3e2443-110228

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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-Section 45
-Paragraph 28
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-Publisher FASB
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-Topic 360
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-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=109226691&loc=d3e2941-110230

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- Definition

Foreign exchange rate used to translate amounts denominated in functional currency to reporting currency.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 830
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- Definition

Amount of gain (loss) on termination of lease before expiration of lease term.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 40
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=77888415&loc=SL77918607-209975

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- Definition

The cash inflow associated with the amount received from the sale of a portion of the company's business, for example a segment, division, branch or other business, during the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
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-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3179-108585

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- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

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