Partnership Distributions - Cash Distributions Tables (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019
Distribution Made to Limited Partner [Line Items]
Total quarterly per-unit distribution	$ 0.32700	$ 0.32300	$ 0.31900	$ 0.31500	$ 0.31100	$ 0.31100	$ 0.31100	$ 0.31100	$ 0.62200	$ 0.62000	$ 0.61800	$ 0.61000
Total quarterly cash distribution	$ 134,749	$ 134,862	$ 134,662	$ 132,969	$ 131,265	$ 132,255	$ 140,900	$ 140,893	$ 281,786	$ 280,880	$ 279,959	$ 276,324
WES Operating [Member]
Distribution Made to Limited Partner [Line Items]
Total quarterly cash distribution	$ 140,217	$ 140,217	$ 140,217	$ 137,030	$ 127,470	$ 143,404	$ 143,404	$ 143,404	$ 290,314	$ 289,676	$ 288,083	$ 283,271