v3.5.0.2
Share-Based Compensation - Summary of Share-Based Compensation Expense (Detail) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2016
Jun. 30, 2015
Jun. 30, 2016
Jun. 30, 2015
Employee Service Share-based Compensation, Aggregate Disclosures [Abstract]        
Share-based compensation expense $ 4.1 $ 3.8 $ 6.1 $ 7.7
Income tax provision related to share-based compensation expense (1.4) (1.1) (2.1) (2.4)
After tax share-based compensation expense $ 2.7 $ 2.7 $ 4.0 $ 5.3