XML 91 R69.htm IDEA: XBRL DOCUMENT v3.8.0.1
Share-Based Payments (Summary of Stock Option Activity) (Details) - Stock Option Plan [Member] - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended 12 Months Ended
Mar. 31, 2018
Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Outstanding beginning balance, Common shares under option 4,459,744  
Granted, Common shares under option 889,169  
Exercised, Common shares under option (202,112)  
Forfeited, Common shares under option (19,662)  
Outstanding ending balance, Common shares under option 5,127,139 4,459,744
Exercisable, Common shares under option 2,675,935  
Outstanding beginning balance, Weighted average exercise price (per share) $ 24.29  
Granted, Weighted average exercise price (per share) 32.16  
Exercised, Weighted average exercise price (per share) 21.34  
Forfeited, Weighted average exercise price (per share) 22.25  
Outstanding ending balance, Weighted average exercise price (per share) 25.78 $ 24.29
Exercisable, Weighted average exercise price (per share) $ 24.13  
Outstanding, Weighted average remaining contractual life (in years) 7 years 8 months 12 days 7 years 6 months
Exercisable, Weighted average remaining contractual life (in years) 6 years 8 months 12 days  
Outstanding beginning balance, Aggregate intrinsic value $ 17,649  
Exercised, Aggregate intrinsic value 2,215  
Outstanding ending balance, Aggregate intrinsic value 30,313 $ 17,649
Exercisable, Aggregate intrinsic value $ 19,839