Transactions with Affiliates - Omnibus Agreement Tables (Details) - Omnibus Agreement [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Amounts reimbursed to Occidental	$ 4,693	$ 3,164	$ 2,084
WES Operating [Member]
Related Party Transaction [Line Items]
Amounts reimbursed to Occidental	88,104	50,486	41,112
General and Administrative Expenses [Member]
Related Party Transaction [Line Items]
Amounts reimbursed to Occidental	604	269	263
General and Administrative Expenses [Member] | WES Operating [Member]
Related Party Transaction [Line Items]
Amounts reimbursed to Occidental	84,039	35,077	31,733
Public Company Expenses [Member]
Related Party Transaction [Line Items]
Amounts reimbursed to Occidental	4,089	2,895	1,821
Public Company Expenses [Member] | WES Operating [Member]
Related Party Transaction [Line Items]
Amounts reimbursed to Occidental	$ 4,065	$ 15,409	$ 9,379