Annual report pursuant to Section 13 and 15(d)

Share-Based Compensation and Other Compensation Matters (Details 6)

v3.3.1.900
Share-Based Compensation and Other Compensation Matters (Details 6)
$ / shares in Units, $ in Thousands
12 Months Ended
Mar. 05, 2015
shares
Mar. 06, 2014
USD ($)
shares
Mar. 01, 2013
USD ($)
shares
Mar. 02, 2012
USD ($)
shares
Dec. 31, 2015
USD ($)
Percentile_Rank
$ / shares
shares
Dec. 31, 2014
USD ($)
$ / shares
shares
Dec. 31, 2013
USD ($)
$ / shares
shares
May. 31, 2010
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Decrease in tax benefit from share-based compensation         $ 513 $ 3 $ 122  
Stock Options [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Expiration period         10 years      
Restricted shares [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Aggregate intrinsic value of vested shares         $ 4,900 $ 4,900 $ 6,300  
Stock awards granted (in shares or units) | shares         201,024 216,607 193,833  
Grant date fair value (in dollars per share) | $ / shares         $ 28.69 $ 26.73 $ 25.91  
Vested (in shares) | shares         (202,781) (182,213) (241,487)  
Vested (in dollars per share) | $ / shares         $ 26.07 $ 28.56 $ 30.97  
Unrecognized compensation cost         $ 6,300      
Expected weighted average period during which unrecognized compensation cost will be recognized         2 years      
Restricted shares [Member] | Minimum [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Estimated pre-vesting forfeitures (as a percent)         0.00%      
Restricted shares [Member] | Maximum [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Estimated pre-vesting forfeitures (as a percent)         5.00%      
Performance share units [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Performance period of the award         3 years      
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      
Grant date fair value (in dollars per share) | $ / shares         $ 36.76 $ 35.09 $ 26.84  
Estimated pre-vesting forfeitures (as a percent)         0.00%      
Unrecognized compensation cost         $ 1,700      
Expected weighted average period during which unrecognized compensation cost will be recognized         2 years      
Phantom Share Units (PSUs) [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Aggregate intrinsic value of vested shares         $ 413      
Stock awards granted (in shares or units) | shares         24,056      
Aggregate grant date fair value         $ 642      
Grant date fair value (in dollars per share) | $ / shares         $ 26.70      
Vested (in shares) | shares         (15,485)      
Vested (in dollars per share) | $ / shares         $ 26.77      
Options [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Aggregate intrinsic value of options exercised         $ 300 $ 225 $ 258  
Deferred Share Awards [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Estimated pre-vesting forfeitures (as a percent)         0.00%      
Unrecognized compensation cost         $ 223      
Amended and Restated 2008 Omnibus Equity and Incentive Plan [Member] | Maximum [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Number of common shares of beneficial interest authorized to be issued | shares               5,900,000.0
2014 PSU Grants [Member] | Performance share units [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Stock awards granted (in shares or units) | shares   49,103            
Aggregate grant date fair value   $ 1,723            
2012 PSU Grants [Member] | Performance share units [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Shares issued for PSU Awards Vested in Period (in shares) | shares 40,309              
Stock awards granted (in shares or units) | shares       54,070        
Aggregate grant date fair value       $ 1,772        
2013 PSU Grants [Member] | Performance share units [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Stock awards granted (in shares or units) | shares     69,579          
Aggregate grant date fair value     $ 1,867          
2013 and 2014 PSU Grants [Member] | Performance share units [Member] | Former Chief Financial Officer [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Shares issued for PSU Awards Vested in Period (in shares) | shares 15,289