Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of Unrecognized Tax Benefits
Balance at January 1,	$ 5.2	$ 7.4
Additions for Tax Positions of Current Year	0.8	0.4
Additions for Tax Positions of Prior Years	3.2	4.1
Reductions for Tax Positions of Prior Years	(0.1)	(6.7)
Balance at December 31,	9.1	5.2
Gross unrecognized tax benefits that would affect the annual effective income tax rate	9.1
Unrealized tax benefits expected to change in next twelve months	0.6
Accrual for the payment of interest and penalties	$ 0.6	$ 0.1