Long Term Debt and Financing Arrangements (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Long-term debt	$ 989.5	$ 595.9
Senior Notes | Senior notes at 5.95%
Debt Instrument [Line Items]
Long-term debt	$ 298.9	$ 298.8
Interest rate, stated percentage	5.95%	5.95%
Senior Notes | Senior notes at 3.625%
Debt Instrument [Line Items]
Long-term debt	$ 297.2	$ 297.1
Interest rate, stated percentage	3.625%	3.625%
Senior Notes | Senior notes at 3.35%
Debt Instrument [Line Items]
Long-term debt	$ 393.4	$ 0.0
Interest rate, stated percentage	3.35%