Goodwill and Intangibles - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Goodwill impairment	$ 0
Impairment of intangible assets (excluding goodwill)	0
Amortization expense for intangible assets	28,400,000	$ 28,400,000	$ 28,200,000
Estimated amortization expense for intangible assets in 2018	28,400,000
Estimated amortization expense for intangible assets in 2019	28,400,000
Estimated amortization expense for intangible assets in 2020	28,400,000
Estimated amortization expense for intangible assets in 2021	28,400,000
Estimated amortization expense for intangible assets in 2022	$ 28,400,000
Western Gas Partners, LP [Member] | Platte Valley [Member]
Finite-Lived Intangible Assets [Line Items]
Straight-line basis of amortization	50 years
Western Gas Partners, LP [Member] | Chipeta [Member]
Finite-Lived Intangible Assets [Line Items]
Straight-line basis of amortization	10 years
Western Gas Partners, LP [Member] | Delaware Basin Midstream LLC [Member]
Finite-Lived Intangible Assets [Line Items]
Straight-line basis of amortization	30 years