Transactions with Affiliates - Gains (Losses) on Commodity Price Swap Agreements Table (Details) - Western Gas Partners, LP [Member] - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Gains (losses) on commodity price swap agreements related to sales and purchases
Gains (losses) on commodity price swap agreements		$ 28,457	$ 66,292	$ 54,868
Sales [Member]
Gains (losses) on commodity price swap agreements related to sales and purchases
Gains (losses) on commodity price swap agreements	[1]	71,034	191,236	123,360
Sales [Member] | Natural Gas [Member]
Gains (losses) on commodity price swap agreements related to sales and purchases
Gains (losses) on commodity price swap agreements	[1]	11,116	45,978	9,494
Sales [Member] | Natural Gas Liquids [Member]
Gains (losses) on commodity price swap agreements related to sales and purchases
Gains (losses) on commodity price swap agreements	[1]	59,918	145,258	113,866
Purchases [Member]
Gains (losses) on commodity price swap agreements related to sales and purchases
Gains (losses) on commodity price swap agreements	[2]	$ (42,577)	$ (124,944)	$ (68,492)

[1] Reported in affiliate Natural gas and natural gas liquids sales in the consolidated statements of operations in the period in which the related sale is recorded.

[2] Reported in Cost of product in the consolidated statements of operations in the period in which the related purchase is recorded.