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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Derivative Financial Instruments (Details)	12 Months Ended
Derivative Financial Instruments (Details)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2018 EUR (€)	Jun. 22, 2018 EUR (€)
Euro-denominated notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Unrealized translation loss on net investment hedge included in accumulated other comprehensive loss, net of taxes	$ 500,000	$ 35,700,000
Designated as economic hedges \| Forward contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Unrealized translation loss on net investment hedge included in accumulated other comprehensive loss, net of taxes	4,200,000	4,200,000
Not designated as hedges \| Forward contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loss associated with forward contracts included in interest and other expenses			$ 1,600,000
Gain associated with forward contracts included in interest and other expenses	2,200,000	$ 0
€400 due September 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Principal amount \| €				€ 400,000,000
€400 due September 2022 \| Designated as economic hedges \| Euro-denominated notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Principal amount	456,800,000			400,000,000
€500 due June 2026
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Principal amount \| €				€ 500,000,000
Senior notes \| €500 due June 2026
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Principal amount	$ 567,800,000				€ 500,000,000