Acquisitions and Divestitures - Impact of the Deferred Purchase Price Obligation - Anadarko Table (Details) - USD ($) $ in Thousands		3 Months Ended						9 Months Ended	12 Months Ended
		Sep. 30, 2016		Jun. 30, 2016		Mar. 31, 2016		Sep. 30, 2016	Dec. 31, 2015		Mar. 02, 2015
Property, Plant and Equipment [Line Items]
Deferred purchase price obligation - Anadarko, present value	[1]	$ 16,425						$ 16,425	$ 188,674	[2]
Western Gas Partners, LP [Member] | Deferred Purchase Price Obligation - Anadarko [Member] | Delaware Basin JV Gathering LLC [Member]
Property, Plant and Equipment [Line Items]
Deferred purchase price obligation - Anadarko, present value		16,425		$ 29,150		$ 193,211		16,425	188,674		$ 174,276	[3]
Accretion expense		(1,173)	[4]	(15,461)	[4]	4,537	[5]	(12,097)	14,398	[5]
Revision to Deferred purchase price obligation – Anadarko	[6]	(11,552)		(148,600)
Deferred purchase price obligation - Anadarko, future value		$ 22,920		$ 41,666		$ 282,807		$ 22,920	$ 282,807		$ 282,807

[1] See Note 2.

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

[3] WES acquired Delaware Basin JV Gathering LLC (“DBJV”) from Anadarko. DBJV owns a 50% interest in a gathering system and related facilities. The DBJV gathering system and related facilities (the “DBJV system”) are 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. At the acquisition date, WES estimated the future payment would be $282.8 million, the net present value of which was $174.3 million. For further information, including revisions to the estimated future payment, see DBJV acquisition—deferred purchase price obligation - Anadarko below.

[4] Interest expense on the consolidated statements of operations includes financing-related accretion revisions of $(1.2) million and $(12.1) million for the three and nine months ended September 30, 2016, respectively.

[5] Accretion expense was recorded as a charge to Interest expense on the consolidated statements of operations.

[6] Recorded as revisions within Common units on the consolidated balance sheets and consolidated statement of equity and partners’ capital.