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Share-Based Compensation - 2012 Equity Incentive Plan Narrative (Details) - shares
9 Months Ended
Sep. 30, 2021
Sep. 30, 2020
Jun. 30, 2021
May 31, 2021
Class of Stock [Line Items]        
Purchase period 6 months      
Purchase price of common stock 85.00%      
2021 Employee Stock Purchase Plan | Class A common shares/units        
Class of Stock [Line Items]        
Number of shares available to grant (in shares)     3,000,000 9,544,095
2021 Employee Stock Purchase Plan | Restricted share units | Minimum        
Class of Stock [Line Items]        
Award vesting period 1 year 1 year    
2021 Employee Stock Purchase Plan | Restricted share units | Maximum        
Class of Stock [Line Items]        
Award vesting period 3 years 3 years    
2021 Employee Stock Purchase Plan | Restricted share units | Non-Management Trustees        
Class of Stock [Line Items]        
Award vesting period 1 year 1 year    
2021 Employee Stock Purchase Plan | Performance Share Units (PSU's)        
Class of Stock [Line Items]        
Award vesting period 3 years      
Service period 3 years      
2021 Employee Stock Purchase Plan | Performance Share Units (PSU's) | Minimum        
Class of Stock [Line Items]        
Percentage of units expected to vest (in percent) 0.00%      
2021 Employee Stock Purchase Plan | Performance Share Units (PSU's) | Maximum        
Class of Stock [Line Items]        
Percentage of units expected to vest (in percent) 200.00%