XML 117 R102.htm IDEA: XBRL DOCUMENT v3.10.0.1
Share-Based Compensation and Capital Stock - Summary Of Activity Related To PVRSU Grants (Details) - Performance Vested Restricted Stock Units - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Performance vested restricted stock units granted at target (in shares) 100,919 162,523 89,944
Weighted average grant date fair value (in dollars per share) $ 81.25 $ 60.63 $ 47.85
Aggregate grant date fair value $ 8,200 $ 9,853 $ 4,304
Stock units forfeited (in shares) 27,255 74,734 54,556
Minimum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Requisite service period 36 months 30 months 9 months
Maximum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Requisite service period 39 months 36 months 43 months