XML 132 R117.htm IDEA: XBRL DOCUMENT v3.10.0.1
Share-based compensation plans - Narratives (Details)
$ in Thousands
12 Months Ended
Dec. 31, 2018
USD ($)
share_based_plan
shares
Dec. 31, 2017
USD ($)
shares
Dec. 31, 2016
USD ($)
Dec. 31, 2012
shares
Dec. 31, 2010
shares
Jun. 30, 2009
shares
Share-based compensation plans            
Number of share-based compensation plans | share_based_plan 2          
Compensation cost | $ $ 5,364 $ 5,809 $ 6,272      
Cash received from exercised options and vested awards | $ 7 $ 305 $ 17      
Total unrecognized compensation cost related to unexercised stock options and unvested share awards | $ $ 8,798          
Total unrecognized compensation cost related to unexercised stock options and unvested share awards, recognition period (in months) 31 months          
2009 share award and incentive plan | Class A common shares            
Share-based compensation plans            
Number of shares reserved for issuance           1,084,500
Increase in number of shares authorized (in shares)       5,000,000 4,000,000  
Share options | Class A common shares            
Share-based compensation plans            
Award expiration period 10 years          
Share options | 2004 stock option plans | Class A common shares            
Share-based compensation plans            
Award expiration period 10 years          
Award vesting period 3 years          
Number of shares available for grant 0          
Fair value of options exercised | $ $ 10          
Number of options vested during the period 0          
Granted (in shares) 0          
Share options | 2004 stock option plan | Class A common shares            
Share-based compensation plans            
Maximum number of options to purchase class A common shares under the plan (in shares) 1,000,000          
Number of shares reserved for issuance 0          
Share options | 2009 share award and incentive plan | Class A common shares            
Share-based compensation plans            
Fair value of options exercised | $ $ 262          
Number of options vested during the period 363,740          
Granted (in shares) 0 581,300        
Total fair value of stock options granted | $ $ 0          
Fair value of options that became exercisable during the period | $ $ 1,055          
Deferred shares | Class A common shares            
Share-based compensation plans            
Award expiration period 4 years          
Deferred shares | 2009 share award and incentive plan | Class A common shares            
Share-based compensation plans            
Number of shares reserved for issuance 1,559,022          
Fair value of awards issued during the period | $ $ 9,247          
Fair value of shares vested in the period | $ $ 4,258          
Options, vested and expected to vest, outstanding, number 0          
Deferred shares without performance criteria | 2009 share award and incentive plan | Class A common shares            
Share-based compensation plans            
Number of shares reserved for issuance 849,322          
Deferred shares with performance criteria | 2009 share award and incentive plan | Class A common shares            
Share-based compensation plans            
Number of shares reserved for issuance 709,700          
Restricted Stock | 2009 share award and incentive plan | Class A common shares            
Share-based compensation plans            
Options, vested and expected to vest, outstanding, number 0