Other Income (Expense), Net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other Income and Expenses [Abstract]
Loss on debt extinguishment	$ (0.4)	$ (72.3)	$ (11.3)
Gain (loss) on derivative contracts	0.4	(1.8)	(4.9)
Gain on sale of equity investment	11.3	0.0	0.0
Gain on legal settlement	0.0	10.8	0.0
Gain on settlement agreement related to Series B Convertible Preferred Stock	0.0	0.0	103.0
Non-cash change in fair value of preferred stock redemption liability	0.0	0.0	(5.0)
Other income (expense), net	3.5	(6.7)	3.8
Total	$ 14.8	$ (70.0)	$ 85.6