Investments - Investment Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Schedule of Equity Method Investments
Total Investment Loss, Net	$ 18,068	$ 5,621	$ 26,207	$ 5,028
White Cliffs
Schedule of Equity Method Investments
Total Investment Loss, Net	(451)	(716)	(1,715)	(2,605)
Advantage
Schedule of Equity Method Investments
Total Investment Loss, Net	(1,278)	(1,867)	(4,665)	(5,621)
Delaware Crossing
Schedule of Equity Method Investments
Total Investment Loss, Net	1,235	512	2,707	2,050
EPIC Y-Grade
Schedule of Equity Method Investments
Total Investment Loss, Net	20,138	2,000	33,733	3,054
EPIC Crude
Schedule of Equity Method Investments
Total Investment Loss, Net	5,840	6,130	14,713	9,375
EPIC Propane
Schedule of Equity Method Investments
Total Investment Loss, Net	63	0	124	0
Saddlehorn
Schedule of Equity Method Investments
Total Investment Loss, Net	(7,045)	0	(17,383)	0
Other
Schedule of Equity Method Investments
Total Investment Loss, Net	$ (434)	$ (438)	$ (1,307)	$ (1,225)