Transactions with Affiliates - Commodity Price Swap Agreements Tables (Details) - Year 2018 [Member]		Dec. 31, 2018 $ / MMBTU $ / bbl	Dec. 20, 2017 $ / MMBTU $ / bbl
DJ Basin Complex [Member] | Ethane [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price		18.41
Commodity market price	[1]		5.41
DJ Basin Complex [Member] | Propane [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price		47.08
Commodity market price	[1]		28.72
DJ Basin Complex [Member] | Isobutane [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price		62.09
Commodity market price	[1]		32.92
DJ Basin Complex [Member] | Normal Butane [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price		54.62
Commodity market price	[1]		32.71
DJ Basin Complex [Member] | Natural Gasoline [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price		72.88
Commodity market price	[1]		48.04
DJ Basin Complex [Member] | Condensate [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price		76.47
Commodity market price	[1]		49.36
DJ Basin Complex [Member] | Natural Gas (per MMBtu) [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price | $ / MMBTU		5.96
Commodity market price | $ / MMBTU	[1]		2.21
MGR Assets [Member] | Ethane [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price		23.11
Commodity market price	[1]		2.52
MGR Assets [Member] | Propane [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price		52.90
Commodity market price	[1]		25.83
MGR Assets [Member] | Isobutane [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price		73.89
Commodity market price	[1]		30.03
MGR Assets [Member] | Normal Butane [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price		64.93
Commodity market price	[1]		29.82
MGR Assets [Member] | Natural Gasoline [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price		81.68
Commodity market price	[1]		47.25
MGR Assets [Member] | Condensate [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price		81.68
Commodity market price	[1]		56.76
MGR Assets [Member] | Natural Gas (per MMBtu) [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price | $ / MMBTU		4.87
Commodity market price | $ / MMBTU	[1]		2.21

[1] Represents the New York Mercantile Exchange forward strip price as of December 20, 2017, for the 2018 Market Prices, adjusted for product specification, location, basis and, in the case of NGLs, transportation and fractionation costs.