XML 61 R50.htm IDEA: XBRL DOCUMENT v3.7.0.1
Capital - Incentive and Share-based Compensation (Details)
$ / shares in Units, $ in Millions
1 Months Ended 3 Months Ended 6 Months Ended 12 Months Ended
May 31, 2017
USD ($)
shares
Mar. 31, 2017
USD ($)
vesting_installment
shares
Jun. 30, 2016
USD ($)
shares
Feb. 29, 2016
USD ($)
vesting_installment
shares
Jun. 30, 2017
USD ($)
shares
Jun. 30, 2016
USD ($)
Jun. 30, 2017
USD ($)
$ / shares
shares
Jun. 30, 2016
USD ($)
$ / shares
Dec. 31, 2016
USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Weighted-average per unit or share fair value (in USD per share) | $ / shares             $ 13.77    
Expected volatility rate look-back period             6 years    
Age of grantee at which LTIP unit and restricted stock awards immediately vest             60 years    
Period of service, upon completion of which, grantee's LTIP unit and restricted stock awards will immediately vest             10 years    
Awards that Meet Age and Service Requirements for Vesting                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Noncash share-based compensation expense recognized | $         $ 0.2 $ 0.1 $ 0.8 $ 0.5  
Unrecognized compensation expense | $         1.1   $ 1.1    
Unrecognized compensation expense, period for recognition             2 years 5 months 18 days    
Awards that Do Not Meet Age and Service Requirements for Vesting                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Noncash share-based compensation expense recognized | $         3.6 $ 2.5 $ 6.2 4.2  
Unrecognized compensation expense | $         $ 30.2   $ 30.2    
Unrecognized compensation expense, period for recognition             2 years 8 months 18 days    
Long-Term Incentive Plan Units and Restricted Stock [Member]                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Fair value of share-based awards granted in period | $             $ 19.4 $ 18.4  
Weighted-average per unit or share fair value (in USD per share) | $ / shares             $ 13.77 $ 9.60  
Risk free interest rate (as a percent)             1.55% 0.84%  
Expected volatility rate (as a percent)             20.00% 24.00%  
LTIP Units                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Shares granted (in shares) | shares             1,372,574    
Time Based Long-Tern Incentive Plan Unit                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Shares granted (in shares) | shares   47,993   47,168          
Fair value of share-based awards granted in period | $   $ 1.6   $ 1.4         $ 0.1
Performance Based Long-Term Incentive Plan Unit                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Shares granted (in shares) | shares   95,156   112,925          
Fair value of share-based awards granted in period | $   $ 1.0   $ 0.8          
Restricted Stock                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Shares granted (in shares) | shares             34,407    
Time Restricted Shares                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Shares granted (in shares) | shares   34,407   44,198          
Long-Term Incentive Plan Unit and Restricted Stock                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Expected term             2 years 9 months 18 days 2 years 9 months 18 days  
Dividend rate (as a percent)             2.05% 2.10%  
Executive Officer | Time Based Long-Tern Incentive Plan Unit | 2013 Plan Units, granted in March 2017                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Shares granted (in shares) | shares   313,275              
Fair value of share-based awards granted in period | $   $ 6.1              
Number of vesting installments | vesting_installment   3              
Award vesting period   4 years              
Executive Officer | Time Based Long-Tern Incentive Plan Unit | 2013 Plan Units Vesting January 2019                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Shares granted (in shares) | shares       368,225          
Fair value of share-based awards granted in period | $       $ 5.6          
Number of vesting installments | vesting_installment       3          
Award vesting period       4 years          
Executive Officer | Time Based Long-Tern Incentive Plan Unit | 2013 Plan Units Vesting three years after February 2016                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Shares granted (in shares) | shares       62,814          
Fair value of share-based awards granted in period | $       $ 1.0          
Award vesting percentage after three years       30.00%          
Award vesting percentage after four years       30.00%          
Award vesting percentage after five years       40.00%          
Executive Officer | Performance Based Long-Term Incentive Plan Unit | 2013 Plan Units, granted in March 2017                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Shares granted (in shares) | shares   865,742              
Fair value of share-based awards granted in period | $   $ 9.6              
Number of vesting installments | vesting_installment   2              
Award vesting period   3 years              
Executive Officer | Performance Based Long-Term Incentive Plan Unit | 2013 Plan Units Vesting January 2019                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Shares granted (in shares) | shares       1,230,228          
Fair value of share-based awards granted in period | $       $ 8.8          
Number of vesting installments | vesting_installment       2          
Award vesting period       3 years          
Director | Time Based Long-Tern Incentive Plan Unit | 2013 Plan Units, granted In May 2017                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Shares granted (in shares) | shares 50,408                
Fair value of share-based awards granted in period | $ $ 1.0                
Award vesting period 3 years                
Director | Time Based Long-Tern Incentive Plan Unit | 2013 Plan Units Vesting three years after June 2016                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Shares granted (in shares) | shares     43,257            
Fair value of share-based awards granted in period | $     $ 0.8            
Award vesting period     3 years            
2013 Plan                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Number of shares authorized under the plan (in shares) | shares         12,200,000.0   12,200,000.0    
Number of shares that remain available for future issuance (in shares) | shares         7,000,000   7,000,000