Property, Plant and Equipment - Additional Information (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017		Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Impairments		$ 178,374		$ 15,535	$ 515,458
Equity investment impairment loss	[1]	3,110
Western Gas Partners, LP [Member] | Fort Union [Member]
Property, Plant and Equipment [Line Items]
Equity investment impairment loss		3,110	[1],[2]	3,000	9,500
Western Gas Partners, LP [Member] | Granger Complex [Member]
Property, Plant and Equipment [Line Items]
Impairments		158,800
Western Gas Partners, LP [Member] | Granger Complex [Member] | Fair Value, Measurements, Nonrecurring [Member] | Level 3 Inputs [Member] | Income Approach Valuation Technique [Member]
Property, Plant and Equipment [Line Items]
Estimated fair value		48,500
Western Gas Partners, LP [Member] | Equipment [Member]
Property, Plant and Equipment [Line Items]
Impairments		19,600		9,400	14,400
Western Gas Partners, LP [Member] | Granger Straddle Plant [Member]
Property, Plant and Equipment [Line Items]
Impairments		3,700
Western Gas Partners, LP [Member] | Granger Straddle Plant [Member] | Fair Value, Measurements, Nonrecurring [Member] | Level 3 Inputs [Member] | Income Approach Valuation Technique [Member]
Property, Plant and Equipment [Line Items]
Estimated salvage value		600
Western Gas Partners, LP [Member] | Northeast Wyoming Facility [Member]
Property, Plant and Equipment [Line Items]
Impairments		2,000
Western Gas Partners, LP [Member] | Northeast Wyoming Facility [Member] | Fair Value, Measurements, Nonrecurring [Member] | Level 3 Inputs [Member] | Market Approach Valuation Technique [Member]
Property, Plant and Equipment [Line Items]
Estimated salvage value		400
Western Gas Partners, LP [Member] | Newcastle System [Member]
Property, Plant and Equipment [Line Items]
Impairments				6,100
Western Gas Partners, LP [Member] | Newcastle System [Member] | Fair Value, Measurements, Nonrecurring [Member] | Level 3 Inputs [Member] | Income Approach Valuation Technique [Member]
Property, Plant and Equipment [Line Items]
Estimated fair value				$ 3,100
Western Gas Partners, LP [Member] | Red Desert Complex [Member]
Property, Plant and Equipment [Line Items]
Impairments					280,200
Western Gas Partners, LP [Member] | Red Desert Complex [Member] | Fair Value, Measurements, Nonrecurring [Member] | Level 3 Inputs [Member] | Income Approach Valuation Technique [Member]
Property, Plant and Equipment [Line Items]
Estimated salvage value					6,300
Western Gas Partners, LP [Member] | Hilight System [Member]
Property, Plant and Equipment [Line Items]
Impairments		$ 8,200			220,900
Western Gas Partners, LP [Member] | Hilight System [Member] | Fair Value, Measurements, Nonrecurring [Member] | Level 3 Inputs [Member] | Income Approach Valuation Technique [Member]
Property, Plant and Equipment [Line Items]
Estimated fair value					$ 28,800

[1] Recorded in Impairments in the consolidated statements of operations.

[2] WES has a 14.81% interest in Fort Union, a joint venture that owns a gathering pipeline and treating facilities in the Powder River Basin. Anadarko is the construction manager and physical operator of the Fort Union facilities. Certain business decisions, including, but not limited to, decisions with respect to significant expenditures or contractual commitments, annual budgets, material financings, dispositions of assets or amending the owners’ firm gathering agreements, require 65% or unanimous approval of the owners.