Quarterly report pursuant to Section 13 or 15(d)

Leased Properties and Leases - Significant Leases (Details)

v3.19.2
Leased Properties and Leases - Significant Leases (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2019
Jun. 30, 2018
Jun. 30, 2019
Jun. 30, 2018
Dec. 31, 2018
Pinedale LGS [Member]          
Operating Leased Assets [Line Items]          
Percentage of total leased properties 44.40%   44.40%   44.50%
Percentage of leased property revenue 38.80% 35.30% 38.90% 34.10%  
Variable rent $ 1.0 $ 1.1 $ 2.1 $ 1.5  
Grand Isle Gathering System [Member]          
Operating Leased Assets [Line Items]          
Percentage of total leased properties 55.30%   55.30%   55.20%
Percentage of leased property revenue 61.10% 55.60% 61.00% 56.70%  
Portland Terminal Facility [Member]          
Operating Leased Assets [Line Items]          
Percentage of total leased properties 0.00%   0.00%   0.00%
Percentage of leased property revenue 0.00% 9.00% 0.00% 9.10%