Annual report pursuant to Section 13 and 15(d)

Share-Based Compensation and Other Compensation Matters (Narrative) (Details)

v3.19.3.a.u2
Share-Based Compensation and Other Compensation Matters (Narrative) (Details)
$ / shares in Units, $ in Thousands
12 Months Ended
Jan. 01, 2019
USD ($)
$ / shares
shares
Mar. 01, 2016
USD ($)
shares
Mar. 05, 2015
USD ($)
shares
Dec. 31, 2019
USD ($)
form
rank
Percentile_Rank
$ / shares
shares
Dec. 31, 2018
USD ($)
$ / shares
shares
Dec. 31, 2017
USD ($)
$ / shares
shares
May 31, 2017
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Shares exercised (in shares) | shares           5,000  
Options              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Expiration period       10 years      
Decrease in tax benefit from share-based compensation           $ 13  
Aggregate intrinsic value of options exercised           18  
Shares exercised (in shares) | shares       0 0    
Performance Shares, Profit Interest Units and Deferred Share Awards [Member]              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Estimated pre-vesting forfeitures       0.00%      
Performance share units              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Unrecognized compensation cost       $ 630      
Expected weighted average period during which unrecognized compensation cost will be recognized       1 year      
Incremental grant date fair value           236  
The number of percentile ranks to fall between to earn interpolated PSUs between such percentile ranks, conditioned on the percentile rank exceeding 25% | Percentile_Rank       2      
Performance period of the award       3 years      
Restricted shares              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Unrecognized compensation cost       $ 6,500      
Expected weighted average period during which unrecognized compensation cost will be recognized       2 years      
Aggregate intrinsic value       $ 4,900 $ 4,600 $ 5,300  
Stock awards granted (in shares or units) | shares       195,520 219,716 239,479  
Grant date fair value (in dollars per share) | $ / shares       $ 26.56 $ 25.62 $ 33.84  
Restricted shares | Minimum              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Estimated pre-vesting forfeitures       0.00%      
Restricted shares | Maximum              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Estimated pre-vesting forfeitures       7.00%      
Performance-based PIUs              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Unrecognized compensation cost       $ 1,600      
Expected weighted average period during which unrecognized compensation cost will be recognized       2 years      
Percentile ranks to fall between for PIUs | rank       2      
Time-based PIUs              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Unrecognized compensation cost       $ 1,100      
Expected weighted average period during which unrecognized compensation cost will be recognized       2 years      
Stock awards granted (in shares or units) | shares       61,820      
Grant date fair value       $ 1,600      
Grant date fair value (in dollars per share) | $ / shares       $ 26.01      
Vesting period       3 years      
Award vesting rights       33.33%      
Deferred Share Awards              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Unrecognized compensation cost       $ 33      
Aggregate intrinsic value       $ 86 $ 154 $ 508  
Stock awards granted (in shares or units) | shares       3,432 13,832 10,032  
Grant date fair value       $ 95 $ 388 $ 326  
Grant date fair value (in dollars per share) | $ / shares       $ 27.60 $ 28.08 $ 32.47  
Profit Interest Units              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Number of forms of executive compensation | form       2      
2017 Omnibus Equity and Incentive Plan | Maximum              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Number of common shares of beneficial interest authorized to be issued | shares             3,400,000
2019 PIU Grants | Performance-based PIUs              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Stock awards granted (in shares or units) | shares 193,682            
Grant date fair value $ 2,400            
Grant date fair value (in dollars per share) | $ / shares $ 12.47            
Performance period of the award       3 years      
Vesting period       3 years      
Percent of award distribution rights       10.00%      
Baseline Common Share Value (in dollars per share) | $ / shares $ 21.03            
Expected volatility of common shares (as a percent) 21.00%            
Risk-free interest rate (as a percent) 2.51%            
2015 PSU Grants | Performance share units              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Stock awards granted (in shares or units) | shares     45,656        
Grant date fair value     $ 1,678        
2015 PSU Grants | Performance share units | Officer              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Shares issued for PSU awards vested in period (in shares) | shares           13,328  
2016 PSU Grants | Performance share units              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Stock awards granted (in shares or units) | shares   26,299          
Grant date fair value   $ 1,005          
2016 PSU Grants | Performance share units | Officer              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Shares issued for PSU awards vested in period (in shares) | shares         44,757