Acquisitions and Divestitures - Additional Information (Details) - USD ($) $ in Thousands			12 Months Ended
		Mar. 17, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Affiliates [Member]
Property, Plant and Equipment [Line Items]
Cash payment			$ 3,910	$ 716,465	$ 10,903
Settlement of the Deferred purchase price obligation - Anadarko	[1]		37,346	0	0
Deferred Purchase Price Obligation - Anadarko [Member] | Affiliates [Member]
Property, Plant and Equipment [Line Items]
Settlement of the Deferred purchase price obligation - Anadarko	[2]		37,346	0	0
Western Gas Partners, LP [Member] | Helper and Clawson Systems [Member]
Property, Plant and Equipment [Line Items]
Gain (loss) on sale of assets			16,300
Western Gas Partners, LP [Member] | Hugoton System [Member]
Property, Plant and Equipment [Line Items]
Gain (loss) on sale of assets				(12,000)
Goodwill allocated to divestiture				$ 1,600
Western Gas Partners, LP [Member] | Dew and Pinnacle Systems [Member]
Property, Plant and Equipment [Line Items]
Gain (loss) on sale of assets					77,300
Goodwill allocated to divestiture					$ 5,100
Western Gas Partners, LP [Member] | Delaware Basin JV Gathering LLC [Member]
Property, Plant and Equipment [Line Items]
Percentage ownership interest		50.00%
Cash payment	[3]	$ 155,000
Net gain from property exchange			125,700
Western Gas Partners, LP [Member] | Delaware Basin JV Gathering LLC [Member] | Deferred Purchase Price Obligation - Anadarko [Member] | Affiliates [Member]
Property, Plant and Equipment [Line Items]
Settlement of the Deferred purchase price obligation - Anadarko			$ 37,346
Western Gas Partners, LP [Member] | Non-Operated Marcellus Interest [Member]
Property, Plant and Equipment [Line Items]
Percentage ownership interest		33.75%

[1] See Note 2.

[2] Represents the cash payment to Anadarko for the settlement of the Deferred purchase price obligation - Anadarko (see Note 2).

[3] WES acquired the Additional DBJV System Interest from a third party. See Property exchange below.