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Equity-Based Awards, Restricted Unit Awards (Details) - Restricted Common Unit Awards [Member] - USD ($)
$ / shares in Units, $ in Millions
 3 Months Ended
Mar. 31, 2017
Mar. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Vesting rate of restricted common unit awards 25.00%  
Summary of awards activity, equity instruments other than options [Roll Forward]    
Beginning of period (in units) 682,294  
Vested (in units) (665,920)  
Forfeited (in units) (1,250)  
End of period (in units) 15,124  
Restricted units outstanding, weighted-average grant date fair value [Roll Forward]    
Weighted-average grant date fair value per unit, at beginning of period (in dollars per unit) [1] $ 28.61  
Vested weighted-average grant date fair value per unit (in dollars per unit) [1] 28.56  
Forfeited weighted-average grant date fair value per unit (in dollars per unit) [1] 31.07  
Weighted-average grant date fair value per unit, at end of period (in dollars per unit) [1] $ 30.74  
Summary of awards activity, equity instruments other than options, additional disclosures [Abstract]    
Cash distributions paid to restricted common unitholders $ 0.3 $ 0.8
Total intrinsic value of our restricted common unit awards that vested during period $ 18.5 $ 26.8
[1] Determined by dividing the aggregate grant date fair value of awards (before an allowance for forfeitures) by the number of awards issued.