XML 60 R48.htm IDEA: XBRL DOCUMENT v3.10.0.1
Share-based Compensation (Detail) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2018
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Share-based compensation expenses $ 3.7 $ 2.0 $ 7.3 $ 4.2
Restricted Stock Units        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Maximum unrecognized cost for stocks and RSU's $ 25.8   $ 25.8  
Unrecognized compensation cost, weighted average period of recognition     2 years 1 month 21 days  
Time Based Awards        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Vesting period     3 years  
Awards with Performance Conditions | 2015 LTIP        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Vesting period     1 year  
Awards with Performance Conditions | 2016 LTIP        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Requisite service period     2 years  
Awards with Performance Conditions | 2017 LTIP        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Vesting period     3 years  
Performance measurement period     1 year  
Requisite service period     2 years  
Performance adjustment percent     25.00%