Partnership Distributions - Additional Information (details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2013 Western Gas Partners [Member]		Mar. 31, 2012 Western Gas Partners [Member]
Dividends Payable [Line Items]
Partnership agreement day requirement of distribution of available cash	55 days		45 days
Total Quarterly Distribution per Unit	$ 0.17875	$ 0.03587	$ 0.540	[1]	$ 0.460
Total Cash Distribution	$ 39,100	$ 7,900	$ 70,143	[1]	$ 46,053
Number Of Days In Prorated Period		20 days

[1] On April 17, 2013, the board of directors of WES GP declared a cash distribution to WES unitholders of $0.54 per unit, or $70.1 million in aggregate, including incentive distributions. The cash distribution is payable on May 13, 2013, to WES unitholders of record at the close of business on April 30, 2013.