Other Income, Net (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	May 23, 2012
Other Income and Expenses [Abstract]
Interest income	$ 0.0	$ 0.0	$ 0.0	$ 0.1
Realized gain on investments	0.8	0.1	2.2	0.4
Loss on extinguishment of debt	0.0	0.0	0.0	(11.1)
All other income (expense), net	0.7	(0.1)	0.9	0.2
Other income (expense), net	$ 1.5	$ 0.0	$ 3.1	(10.4)
Senior Notes | Senior Notes Due 2020
Debt Instrument
Debt instrument contractual rate (percent)					8.25%
Redemption premium				8.2
Write off of deferred debt issuance cost				$ 2.9