Debt (Schedule of Loss on Debt Extinguishment) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Feb. 10, 2017
Debt Instrument [Line Items]
Loss (gain) on debt extinguishment	$ 0.0	$ 2.6	$ (14.1)
Financing Agreement, April 2014
Debt Instrument [Line Items]
Loss (gain) on debt extinguishment		1.1
Financing Arrangement, February 2017
Debt Instrument [Line Items]
Debt issuance costs				$ 4.7
Loss (gain) on debt extinguishment		1.5
Discharge of Debt | Financing Arrangement, February 2017
Debt Instrument [Line Items]
Debt issuance costs		1.5
Long-term Debt | Financing Arrangement, February 2017
Debt Instrument [Line Items]
Debt issuance costs		$ 3.2