Fair Value Measurements and Risk - Narrative (Details) € in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 EUR (€) Currency country	Sep. 30, 2018 USD ($) Currency country	Apr. 03, 2018 EUR (€)	Apr. 03, 2018 USD ($)	Feb. 03, 2015 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of countries in which entity operates | country					60	60
Number of currencies used | Currency					30	30
Maturities in which forward contracts are designated as cash flow hedges or forecasted repayments of intercompany loans			36 months
Currency contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total contract value						$ 115,300,000
Variable-to-fixed cross-currency derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amount of debt hedged								$ 600,000,000
Fixed interest rate							2.0231%	2.0231%
Variable-to-fixed cross-currency derivatives | 2025 Term Loan
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total contract value | €							€ 490.1
Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amount of debt hedged								$ 100,000,000	$ 250,000,000
Fixed interest rate							2.775%	2.775%	2.393%
Net Investment Hedging
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred intercompany royalties designated as hedging instrument | €					€ 16.9
Amount of Gain (Loss) Reclassified from OCI into Income	$ 0	$ 0	$ 0	$ 0
Net Investment Hedging | Currency Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total contract value | €					€ 170.0
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net	$ 700,000		$ 1,400,000