Derivative Financial Instruments - Schedule of Change in Fair Value of Foreign Currency Forward Exchange Contracts Under Hedge Designations (Details) - Designated as Hedging Instrument - Foreign Currency Forward Exchange Contracts - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivative [Line Items]
Unrealized losses at beginning of period, net of tax	$ (25.9)	$ (15.0)	$ (9.2)
Losses reclassified to net sales	8.9	14.4	11.8
Increase (decrease) in fair value	25.6	(25.3)	(17.6)
Unrealized gains (losses) at end of period, net of taxes	$ 8.6	$ (25.9)	$ (15.0)