Stock-Based Compensation - Schedule of Stock-Based Compensation Expense by Type of Award (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 17.9	$ 17.2	$ 18.9
Tax benefit from stock options exercised during the period	9.2	5.8	5.3
Non-qualified stock options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	3.3	3.6	3.8
RSUs
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	6.4	6.0	6.0
PRSUs
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	7.9	7.4	8.8
Employee stock purchase plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 0.3	$ 0.2	$ 0.3