Fair Value of Financial Instruments - Financial assets and liabilities accounted for at fair value on a recurring basis by level within the fair value hierarchy (Details) - Estimate of Fair Value Measurement - Fair Value, Measurements, Recurring - Foreign Currency Exchange Contracts - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative liabilities, current	$ 2.4	$ 1.8
Derivatives assets, current		0.1
Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative liabilities, current	$ 2.4	1.8
Derivatives assets, current		$ 0.1