Equity - Additional Information (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2016
Sep. 30, 2015
Sep. 30, 2016
Sep. 30, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]        
Stock-based compensation expense $ 6.1 $ 4.2 $ 16.9 $ 13.8
Total unrecognized compensation expense $ 47.0   $ 47.0