Annual report pursuant to Section 13 and 15(d)

Stock Based Compensation - Restricted Share Awards with Performance and Service Conditions Narrative (Details)

v3.19.3.a.u2
Stock Based Compensation - Restricted Share Awards with Performance and Service Conditions Narrative (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Fair value of restricted share units vested $ 6.5 $ 6.1 $ 5.9
Restricted Share Awards      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Compensation costs not yet recognized $ 5.9    
Recognition period for compensation costs not yet recognized 22 months