XML 58 R45.htm IDEA: XBRL DOCUMENT v3.8.0.1
Stock-Based Compensation - Additional Information (Detail) - USD ($)
$ in Millions
1 Months Ended 6 Months Ended
May 31, 2017
Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Aggregate intrinsic value of options exercised in period   $ 36.5
Fair value of options vested in period   4.4
Employee Stock Option    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Unrecognized stock-based compensation expense   $ 11.6
Unrecognized stock-based compensation expense, weighted-average recognition period   2 years 6 months
Restricted Stock Units    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Unrecognized stock-based compensation expense   $ 44.6
Unrecognized stock-based compensation expense, weighted-average recognition period   2 years 1 month 6 days
Restricted share unit issued   291,000
Performance Based Restricted Stock Units    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Restricted share unit issued 159,000