Acquisitions and Divestitures - Additional Information (Details) - USD ($) $ in Thousands					1 Months Ended			12 Months Ended
		Mar. 02, 2015		Nov. 25, 2014	Aug. 31, 2012	Jul. 31, 2009	Dec. 31, 2008	Dec. 31, 2015	Dec. 31, 2014		Dec. 31, 2013		Sep. 30, 2010
Property, Plant and Equipment [Line Items]
Deferred purchase price obligation - Anadarko	[1]							$ 188,674	$ 0	[2]
Revenues and other								1,561,372	1,382,868	[3]	$ 1,085,482	[3]
Operating expenses								1,655,257	965,426	[3]	784,883	[3]
Goodwill								389,686	389,087	[2]
Delaware Basin JV Gathering LLC [Member]
Property, Plant and Equipment [Line Items]
Revenues and other									62,112		32,545
Delaware Basin Midstream LLC [Member]
Property, Plant and Equipment [Line Items]
Revenues and other									12,500
Operating expenses									10,400
Western Gas Partners, LP [Member] | Dew and Pinnacle Systems [Member]
Property, Plant and Equipment [Line Items]
Proceeds from the sale of assets								145,600
Gain on divestiture and other, net								77,300
Goodwill								$ 5,100
Western Gas Partners, LP [Member] | Newcastle [Member]
Property, Plant and Equipment [Line Items]
Percentage acquired							50.00%	50.00%
Western Gas Partners, LP [Member] | Fort Union [Member]
Property, Plant and Equipment [Line Items]
Equity investment ownership							14.81%
Western Gas Partners, LP [Member] | Chipeta Processing Limited Liability Company [Member]
Property, Plant and Equipment [Line Items]
Percentage acquired					24.00%	51.00%		75.00%
Western Gas Partners, LP [Member] | White Cliffs [Member]
Property, Plant and Equipment [Line Items]
Equity investment ownership													10.00%
Western Gas Partners, LP [Member] | Delaware Basin JV Gathering LLC [Member]
Property, Plant and Equipment [Line Items]
Percentage acquired		50.00%	[4]					50.00%
Western Gas Partners, LP [Member] | Delaware Basin JV Gathering LLC [Member] | Deferred Purchase Price Obligation - Anadarko [Member]
Property, Plant and Equipment [Line Items]
Discount rate percentage								10.00%
Deferred purchase price obligation - Anadarko								$ 188,700
Interest expense, related party								14,400	$ 0		$ 0
Western Gas Partners, LP [Member] | Delaware Basin JV Gathering LLC [Member] | Deferred Purchase Price Obligation - Anadarko [Member] | Level 3 Inputs [Member]
Property, Plant and Equipment [Line Items]
Deferred purchase price obligation to Anadarko - future value		$ 282,800
Deferred purchase price obligation to Anadarko - acquisition date value	[4]	$ 174,276
Western Gas Partners, LP [Member] | Delaware Basin Midstream LLC [Member]
Property, Plant and Equipment [Line Items]
Percentage acquired	[5]			100.00%
Post-closing purchase price adjustments								3,500
Western Gas Partners, LP [Member] | Delaware Basin Midstream LLC [Member] | Level 3 Inputs [Member]
Property, Plant and Equipment [Line Items]
Goodwill								$ 284,749

[1] See Note 2.

[2] Financial information has been recast to include the financial position and results attributable to the DBJV system. See Note 1 and Note 2.

[3] Financial information has been recast to include the financial position and results attributable to the DBJV system. See Note 1 and Note 2.

[4] WES acquired Anadarko’s interest in Delaware Basin JV Gathering LLC (“DBJV”), which owns a 50% interest in a gathering system and related facilities (the “DBJV system”). The DBJV system is located in the Delaware Basin in Loving, Ward, Winkler and Reeves Counties, Texas. WES will make a cash payment on March 31, 2020, to Anadarko as consideration for the acquisition of DBJV. WES currently estimates the future payment will be $282.8 million, the net present value of which was $174.3 million as of the acquisition date. See DBJV acquisition—Deferred purchase price obligation - Anadarko below.

[5] WES acquired Nuevo Midstream, LLC (“Nuevo”) from a third party. Following the acquisition, WES changed the name of Nuevo to Delaware Basin Midstream, LLC (“DBM”). The assets acquired include cryogenic processing plants, a gas gathering system, and related facilities and equipment, which are collectively referred to as the “DBM complex” and serve production from Reeves, Loving and Culberson Counties, Texas and Eddy and Lea Counties, New Mexico. See DBM acquisition below for further information, including the final allocation of the purchase price.