Partnership Distributions - Cash Distributions Tables (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Sep. 30, 2018		Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017
Distribution Made to Limited Partner [Line Items]
Total quarterly distribution per unit	$ 0.59500	[1]	$ 0.58250	$ 0.56875	$ 0.54875	$ 0.53750	$ 0.52750	$ 0.49125
Total quarterly cash distribution	$ 130,268	[1]	$ 127,531	$ 124,518	$ 120,140	$ 117,677	$ 115,487	$ 107,549
Western Gas Partners, LP [Member]
Distribution Made to Limited Partner [Line Items]
Total quarterly distribution per unit	$ 0.965	[2]	$ 0.950	$ 0.935	$ 0.920	$ 0.905	$ 0.890	$ 0.875
Total quarterly cash distribution	$ 230,239	[2]	$ 225,691	$ 221,133	$ 216,586	$ 212,038	$ 207,491	$ 188,753

[1] The Board of Directors declared a cash distribution to WGP unitholders for the third quarter of 2018 of $0.59500 per unit, or $130.3 million in aggregate. The cash distribution is payable on November 21, 2018, to WGP unitholders of record at the close of business on October 31, 2018.

[2] The Board of Directors of WES GP declared a cash distribution to WES unitholders for the third quarter of 2018 of $0.965 per unit, or $230.2 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 13, 2018, to WES unitholders of record at the close of business on October 31, 2018.