Long Term Debt and Financing Arrangements (Details) - USD ($) $ in Millions	Sep. 30, 2016	Mar. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Long-term debt	$ 990.1		$ 595.9
Senior Notes | Senior notes at 5.95%
Debt Instrument [Line Items]
Long-term debt	$ 299.2		$ 298.8
Interest rate, stated percentage	5.95%		5.95%
Senior Notes | Senior notes at 3.625%
Debt Instrument [Line Items]
Long-term debt	$ 297.4		$ 297.1
Interest rate, stated percentage	3.625%		3.625%
Senior Notes | Senior notes at 3.35%
Debt Instrument [Line Items]
Long-term debt	$ 393.5		$ 0.0
Interest rate, stated percentage	3.35%	3.35%