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Incentive Plan (Market Performance-Based Awards) (Details)
$ in Millions
12 Months Ended
Feb. 28, 2017
Jan. 01, 2017
shares
Feb. 16, 2016
Jan. 01, 2016
Feb. 24, 2015
Dec. 31, 2017
USD ($)
simulation
shares
Dec. 31, 2016
USD ($)
shares
Dec. 31, 2015
USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Units granted (in shares)           73,449 1,416  
Market Performance-Based Awards                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Performance period           3 years    
Number of trials run | simulation           100,000    
Expected volatility rate 23.00% 25.00% 26.00% 22.00% 24.00%      
Risk free interest rate 1.43% 1.49% 0.89% 1.32% 1.00%      
Fair value of awards | $           $ 74.9    
Expected service period           4 years    
Unearned compensation | $           $ 24.7 $ 25.6  
Compensation expense | $           9.6 7.9 $ 4.1
Capitalized expense related to construction and leasing activities | $           $ 2.3 $ 1.9 $ 4.1
Market Performance-Based Awards | 2014 Performance Grant                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Performance period           3 years    
Market Performance-Based Awards | 2015 Performance Grant                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Performance period           3 years    
Market Performance-Based Awards | 2015 Performance Grant | Below Threshold Level (less than)                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Vesting percentage           0.00%   0.00%
Performance threshold percentage               (3.00%)
Market Performance-Based Awards | 2015 Performance Grant | Threshold Level                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Vesting percentage           25.00%   25.00%
Performance threshold percentage               (3.00%)
Market Performance-Based Awards | 2015 Performance Grant | Target Level                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Vesting percentage           50.00%   50.00%
Performance threshold percentage               1.00%
Market Performance-Based Awards | 2015 Performance Grant | High Level (greater than)                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Vesting percentage           100.00%   100.00%
Performance threshold percentage               5.00%
Market Performance-Based Awards | 2015 Performance Grant | Vesting on February 27, 2018                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Vesting percentage           50.00%    
Market Performance-Based Awards | 2015 Performance Grant | Vesting on February 27, 2019                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Vesting percentage           50.00%    
Market Performance-Based Awards | 2016 Performance Grant | Below Threshold Level (less than)                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Vesting percentage             0.00%  
Performance threshold percentage             (3.00%)  
Market Performance-Based Awards | 2016 Performance Grant | Threshold Level                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Vesting percentage             25.00%  
Performance threshold percentage             (3.00%)  
Market Performance-Based Awards | 2016 Performance Grant | Target Level                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Vesting percentage             50.00%  
Performance threshold percentage             1.00%  
Market Performance-Based Awards | 2016 Performance Grant | High Level (greater than)                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Vesting percentage             100.00%  
Performance threshold percentage             5.00%  
Class D Units                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Shares vested (in shares)   399,250            
Units granted (in shares)           2,029,908    
Restricted Stock Units (RSUs)                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Shares vested (in shares)   138,567       49,707    
Units granted (in shares)           543,923