Investments - Summary of Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Schedule of Equity Method Investments
Investments	$ 899,468	$ 660,778
White Cliffs
Schedule of Equity Method Investments
Investments	10,319	10,268
Advantage
Schedule of Equity Method Investments
Investments	71,201	76,834
Delaware Crossing
Schedule of Equity Method Investments
Investments	81,992	68,707
EPIC Y-Grade
Schedule of Equity Method Investments
Investments	183,655	162,850
EPIC Crude
Schedule of Equity Method Investments
Investments	381,073	339,116
EPIC Propane
Schedule of Equity Method Investments
Investments	11,396	3,003
Saddlehorn
Schedule of Equity Method Investments
Investments	$ 159,832	$ 0