Financial Instruments - Gross Notional Amounts for Outstanding Derivatives (Details) - Forward contracts - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Derivatives Designated as Hedging Instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional amounts of outstanding currency forward contracts	$ 109.7	$ 89.1
Derivatives Not Designated as Hedging Instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional amounts of outstanding currency forward contracts	143.7	128.7
Prepaid and other current assets | Derivatives Designated as Hedging Instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional amounts of outstanding currency forward contracts	6.2	2.0
Prepaid and other current assets | Derivatives Not Designated as Hedging Instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional amounts of outstanding currency forward contracts	5.6	2.6
Other accrued liabilities | Derivatives Designated as Hedging Instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional amounts of outstanding currency forward contracts	1.0	0.5
Other accrued liabilities | Derivatives Not Designated as Hedging Instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional amounts of outstanding currency forward contracts	$ 0.6	$ 0.2