Components of Working Capital - Accrued Liabilities Table (details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2015	Dec. 31, 2014
Accrued Liabilities [Line Items]
Accrued interest expense		$ 27,995	$ 24,741
Short-term asset retirement obligations		5,739	1,224
Short-term remediation and reclamation obligations		475	475
Income taxes (receivable) payable		(270)	207
Total accrued liabilities		171,217	170,864	[1]
Western Gas Partners [Member] | Delaware Basin Midstream Limited Liability Company [Member]
Table Text Block Supplement [Abstract]
Post-closing purchase price adjustments		3,500
Accrued Capital Expenditures [Member]
Accrued Liabilities [Line Items]
Other accrued liabilities		94,176	128,856
Accrued Plant Purchases [Member]
Accrued Liabilities [Line Items]
Other accrued liabilities		37,826	14,023
Other Accrued Liabilities [Member]
Accrued Liabilities [Line Items]
Other accrued liabilities	[2]	$ 5,276	$ 1,338

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

[2] Includes $3.5 million of post-closing purchase price adjustments at March 31, 2015, related to WES’s acquisition of DBM.