Partnership Distributions - Cash Distributions Tables (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020
Distribution Made to Limited Partner [Line Items]
Total quarterly per-unit distribution	$ 0.31900	$ 0.31500	$ 0.31100	$ 0.31100	$ 0.31100	$ 0.31100
Total quarterly cash distribution	$ 134,662	$ 132,969	$ 131,265	$ 132,255	$ 140,900	$ 140,893
WES Operating [Member]
Distribution Made to Limited Partner [Line Items]
Total quarterly cash distribution	$ 140,217	$ 137,030	$ 127,470	$ 143,404	$ 143,404	$ 143,404