Partnership Distributions - Cash Distributions Tables (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Sep. 30, 2015		Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014
Distribution Made to Limited Partner [Line Items]
Total quarterly distribution per unit	$ 0.38125	[1]	$ 0.36375	$ 0.34250	$ 0.31250	$ 0.29125	$ 0.27125	$ 0.25000
Total quarterly cash distribution	$ 83,461	[1]	$ 79,630	$ 74,977	$ 68,409	$ 63,756	$ 59,378	$ 54,726
Western Gas Partners, LP [Member]
Distribution Made to Limited Partner [Line Items]
Total quarterly distribution per unit	$ 0.775	[2]	$ 0.750	$ 0.725	$ 0.700	$ 0.675	$ 0.650	$ 0.625
Total quarterly cash distribution	$ 146,160	[2]	$ 139,736	$ 133,203	$ 126,044	$ 111,608	$ 105,655	$ 98,749

[1] On October 14, 2015, the Board of Directors of WGP GP declared a cash distribution to WGP unitholders of $0.38125 per unit, or $83.5 million in aggregate. The cash distribution is payable on November 20, 2015, to WGP unitholders of record at the close of business on November 2, 2015.

[2] On October 14, 2015, the Board of Directors of WES GP declared a cash distribution to WES unitholders of $0.775 per unit, or $146.2 million in aggregate, including incentive distributions, but excluding distributions on WES Class C units (see WES Class C unit distributions below). The cash distribution is payable on November 12, 2015, to WES unitholders of record at the close of business on November 2, 2015.