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Incentive Compensation - Additional Information (Details) - USD ($)
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Cash Bonus, requisite service period 4 years    
Granted, weighted average grant date fair value (in usd per share) $ 17.95 $ 18.48 $ 10.09
Fair value of units vested $ 12,900,000 $ 25,100,000 $ 11,900,000
Cash payments of vested units $ 0 $ 0 $ 0
Restricted Common Units      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Grant of stock units 462,512    
Granted, weighted average grant date fair value (in usd per share) $ 17.95    
Unrecognized compensation cost $ 11.0    
Period of weighted average recognition 1 year 5 months 21 days    
Subordinated Units      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Grant of stock units 0    
Granted, weighted average grant date fair value (in usd per share) $ 0.00    
Restricted Subordinated Units      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Unrecognized compensation cost $ 0    
Performance Units      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Grant of stock units 463,251    
Granted, weighted average grant date fair value (in usd per share) $ 17.94 $ 17.99 $ 11.36
Unrecognized compensation cost $ 8,400,000    
Period of weighted average recognition 1 year 6 months 18 days    
Fair value of units vested $ 1,500,000   $ 3,200,000