Partnership Distributions - Cash Distributions Tables (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018
Distribution Made to Limited Partner [Line Items]
Total quarterly per-unit distribution	$ 0.62000	$ 0.61800	$ 0.61000	$ 0.60250	$ 0.59500	$ 0.58250	$ 0.56875
Total quarterly cash distribution	$ 280,880	$ 279,959	$ 276,324	$ 131,910	$ 130,268	$ 127,531	$ 124,518
WES Operating [Member]
Distribution Made to Limited Partner [Line Items]
Total quarterly per-unit distribution				$ 0.980	$ 0.965	$ 0.950	$ 0.935
Total quarterly cash distribution	$ 289,700	$ 288,100	$ 283,300	$ 234,787	$ 230,239	$ 225,691	$ 221,133