Income Taxes (Reconciliation of Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Tax Credit Carryforwards, Foreign	$ 10.6
Reconciliation of the beginning and ending amount of unrecognized tax benefits
Balance as of beginning of period	2.4	$ 0.5
Increases related to prior year tax positions	0.1	1.0
Decreases related to prior year tax positions	(2.5)
Increases related to current year tax positions		1.4
Settlement		(0.5)
Balance as of end of period	$ 0.0	$ 2.4