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Share-Based Compensation - Narrative (Details)
$ / shares in Units, $ in Millions
12 Months Ended
Oct. 28, 2018
shares
Jun. 20, 2018
USD ($)
trustee
$ / shares
shares
Jan. 29, 2018
$ / shares
shares
Nov. 08, 2017
shares
Jun. 20, 2017
USD ($)
trustee
$ / shares
shares
Jan. 24, 2017
$ / shares
shares
Jun. 15, 2016
USD ($)
trustee
$ / shares
shares
Jan. 26, 2016
$ / shares
shares
Jun. 16, 2015
shares
Dec. 31, 2022
shares
Dec. 31, 2021
shares
Dec. 31, 2020
shares
Dec. 31, 2019
shares
Dec. 31, 2018
USD ($)
tranche
$ / shares
shares
Dec. 31, 2017
USD ($)
$ / shares
shares
Dec. 31, 2016
USD ($)
$ / shares
shares
Dec. 31, 2015
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                  
Expected term of incentive plan after effective date                 10 years                
Common shares available for issuance (in shares)                           839,470      
Common stock issued (in shares) 225,655     226,258                   121,572,155 124,217,616    
General and administrative expense                                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                  
Compensation expense | $                           $ 19.7 $ 21.4 $ 18.5  
Restricted shares                                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                  
Vesting period   1 year                       4 years      
Number of independent trustees | trustee   9     9   9                    
Share based compensation amount | $   $ 0.1         $ 0.1                    
Number of equity awards granted (in shares)   25,600 125,409   25,248 76,424 31,167 136,623                  
Price per share (in dollars per share) | $ / shares   $ 31.25     $ 31.69   $ 28.88                    
Granted (in dollars per share) | $ / shares     $ 29.78     $ 31.47   $ 26.93                  
Restricted shares | Independent Trustee                                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                  
Number of equity awards granted (in shares)   3,200         3,463                    
RSUs                                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                  
Vesting period                           3 years      
Number of tranches | tranche                           2      
Vested (in shares) 225,655     226,258                          
RSUs | Vesting in three years                                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                  
Vesting percentage                           50.00%      
RSUs | Vesting in four years                                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                  
Vesting period                           1 year      
Vesting percentage                           50.00%      
RSUs at target                                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                  
Number of equity awards granted (in shares)     254,615     155,168   277,386                  
RSUs at maximum                                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                  
Number of equity awards granted (in shares)     634,628     386,756   691,385                  
Granted (in dollars per share) | $ / shares                           $ 14.90 $ 15.97 $ 15.57  
LTIP units                                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                  
Equity award, conversion basis (in shares)                           1      
Time-based LTIP Units                                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                  
Number of equity awards granted (in shares)   3,200     3,156                        
Time-based LTIP Units | Independent Trustee                                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                  
Number of equity awards granted (in shares)         3,156                        
Time-based LTIP units at target                                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                  
Number of equity awards granted (in shares)           39,364                      
Market-based LTIP units at target                                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                  
Number of equity awards granted (in shares)           79,924                      
LTIP units at maximum                                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                  
Number of equity awards granted (in shares)           199,211                      
Restricted Shares and Time-Based LTIP Units                                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                  
Vested (in shares)                           407,273 217,449 191,498  
Share based compensation amount | $         $ 0.1                        
Number of equity awards granted (in shares)                           154,209 144,192 167,790  
Granted (in dollars per share) | $ / shares                           $ 30.05 $ 31.51 $ 27.29  
Unvested (in shares)                           425,888 678,952 752,209 776,456
Estimated future compensation expense for unvested shares | $                           $ 6.1      
Weighted average period over which compensation expense will be recorded                           2 years 3 months 18 days      
Restricted Shares and Time-Based LTIP Units | Scenario, Forecast                                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                  
Vested (in shares)                   61,885 87,772 124,959 151,272        
OP Units                                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                  
Conversions in period (in shares)                           3,156      
RSUs and market-based LTIP units                                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                  
Expected term of incentive plan after effective date                           4 years 4 years 4 years  
Vested (in shares)                           367,260 226,258 0  
Number of equity awards granted (in shares)                           634,628 585,967 691,385  
Granted (in dollars per share) | $ / shares                           $ 14.90 $ 15.97 $ 15.57  
Unvested (in shares)                           2,046,644 2,131,947 2,572,768 1,884,110
Estimated future compensation expense for unvested shares | $                           $ 12.4      
Weighted average period over which compensation expense will be recorded                           2 years 1 month 6 days      
Maximum                                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                  
Common shares available for issuance (in shares)                 3,250,000