XML 71 R61.htm IDEA: XBRL DOCUMENT v3.21.2
Share Capital - Changes in Number of Shares of Class A Stock Outstanding (Details) - Class A Stock - shares
3 Months Ended 6 Months Ended
Jun. 30, 2021
Jun. 30, 2020
Jun. 30, 2021
Jun. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]        
Class A Stock outstanding, beginning of period 12,586,043 12,610,740 12,381,778 12,698,703
Issued pursuant to shared-based compensation plans 6,603 25,783 210,868 347,324
Repurchased and canceled pursuant to the stock buy-back 0 191,044 0 600,548
Class A Stock outstanding, end of period 12,592,646 12,445,479 12,592,646 12,445,479