Share-Based Compensation (Details 3) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Share-based compensation expense
Pre-tax compensation expense	$ 5.4	$ 4.7	$ 15.7	$ 14.1
Income tax benefit	(2.0)	(1.7)	(5.8)	(5.2)
Total share-based compensation expense, net of income taxes	3.4	3.0	9.9	8.9
Stock Option Awards
Share-based compensation expense
Pre-tax compensation expense	1.7	1.7	5.1	5.4
Income tax benefit	(0.6)	(0.6)	(1.9)	(2.0)
Total share-based compensation expense, net of income taxes	1.1	1.1	3.2	3.4
Restricted Stock Units, Restricted Stock Awards And Other Share Based Awards
Share-based compensation expense
Pre-tax compensation expense	3.7	3.0	10.6	8.7
Income tax benefit	(1.4)	(1.1)	(3.9)	(3.2)
Total share-based compensation expense, net of income taxes	$ 2.3	$ 1.9	$ 6.7	$ 5.5