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Partnership Units and Related Matters - Additional Information (Details) - USD ($)
$ / shares in Units, $ in Millions
1 Months Ended 3 Months Ended 9 Months Ended
Oct. 31, 2018
Oct. 31, 2015
Sep. 30, 2018
Sep. 30, 2018
Limited Partners Capital Account [Line Items]        
Capital contributions to partnership       $ 540.0
Limited partner capital contribution allocation percentage       98.00%
General partner capital contribution allocation percentage       2.00%
Preferred Units Issued   5,000,000    
Subsequent Event [Member]        
Limited Partners Capital Account [Line Items]        
Distributions declaration month 2018-10      
Distribution declared $ 0.1875      
Distributions payable date Nov. 15, 2018      
Series A Preferred Units [Member]        
Limited Partners Capital Account [Line Items]        
Preferred unit, distribution interest rate   9.00%    
Series A Cumulative Redeemable Perpetual Preferred Units [Member]        
Limited Partners Capital Account [Line Items]        
Distribution to preferred unitholders     $ 2.8 $ 8.4
Series A Cumulative Redeemable Perpetual Preferred Units [Member] | London Interbank Offered Rate (LIBOR)        
Limited Partners Capital Account [Line Items]        
Percentage of variable interest rate for distribution on preferred units upon maturity   7.71%