Other Income, Net (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	May 23, 2012
Other Income and Expenses [Abstract]
Interest income	$ 0.0	$ 0.0	$ 0.0	$ 0.1
Realized gain on investments	0.7	0.3	1.4	0.3
Loss on extinguishment of debt	0.0	(11.1)	0.0	(11.1)
All other income, net	0.3	0.1	0.2	0.3
Other income (expense), net	$ 1.0	(10.7)	$ 1.6	$ (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