Asset Retirement Obligations - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Revisions in estimated liabilities	$ 141,356	$ (10,314)
Gathering Systems and Processing Complexes [Member] \| Western Gas Partners, LP [Member]
Property, Plant and Equipment [Line Items]
Revisions in estimated liabilities	71,800
Third Creek Gathering System [Member] \| Western Gas Partners, LP [Member]
Property, Plant and Equipment [Line Items]
Revisions in estimated liabilities	$ 43,400

Amount of increase (decrease) in the asset retirement obligation from changes in the amount or timing of the estimated cash flows associated with the settlement of the obligation.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 35
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6392603&loc=d3e7123-110846

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)(4)
-URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

Name:	us-gaap_AssetRetirementObligationRevisionOfEstimate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration