Partnership Distributions - Cash Distributions Table (details) (USD $) In Thousands, except Per Share data, unless otherwise specified	1 Months Ended	3 Months Ended
	May 31, 2008	Dec. 31, 2014		Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012
Dividends Payable [Line Items]
Total quarterly distribution per unit		$ 0.31250	[1]	$ 0.29125	$ 0.27125	$ 0.25000	$ 0.23125	$ 0.21375	$ 0.19750	$ 0.17875	$ 0.03587
Total quarterly cash distribution		$ 68,409	[1]	$ 63,756	$ 59,378	$ 54,726	$ 50,620	$ 46,789	$ 43,232	$ 39,128	$ 7,852
Western Gas Partners [Member]
Dividends Payable [Line Items]
Total quarterly distribution per unit	$ 0.300	$ 0.700	[2]	$ 0.675	$ 0.650	$ 0.625	$ 0.600	$ 0.580	$ 0.560	$ 0.540	$ 0.520	$ 0.500	$ 0.480	$ 0.460
Total quarterly cash distribution		$ 126,044	[2]	$ 111,608	$ 105,655	$ 98,749	$ 92,609	$ 83,986	$ 79,315	$ 70,143	$ 65,657	$ 56,346	$ 52,425	$ 46,053

[1] On January 22, 2015, the Board of Directors of WGP GP declared a cash distribution to WGP unitholders of $0.31250 per unit, or $68.4 million in aggregate. The cash distribution was paid on February 20, 2015, to WGP unitholders of record at the close of business on February 2, 2015.

[2] On January 22, 2015, the Board of Directors of WES GP declared a cash distribution to WES unitholders of $0.700 per unit, or $126.0 million in aggregate, including incentive distributions, but excluding distributions on WES Class C units (see WES Class C unit distributions below). The cash distribution was paid on February 12, 2015, to WES unitholders of record at the close of business on February 2, 2015.