Transactions with Affiliates - Additional Information (Details) - USD ($)		1 Months Ended	12 Months Ended
		May 31, 2008	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Note receivable - Anadarko			$ 260,000,000	$ 260,000,000
Capital contribution for the above-market component of swap agreements with Anadarko	[1]		7,407,000	51,618,000	$ 58,551,000
Administrative services fee under the omnibus agreement	[2]		114,591,000	67,195,000	53,949,000
Materials and supplies inventory			23,444,000	9,665,000
Incentive Plans [Member]
Related Party Transaction [Line Items]
Allocated equity-based compensation expense			12,900,000	6,600,000	4,600,000
Unvested equity-based compensation expense			$ 7,900,000
Weighted-average term of unvested awards			1 year 9 months 18 days
Long-Term Incentive Plans [Member]
Related Party Transaction [Line Items]
Units vesting period			3 years
Allocated equity-based compensation expense			$ 1,000,000.0	$ 700,000	$ 600,000
Omnibus Agreement [Member]
Related Party Transaction [Line Items]
Administrative services fee under the omnibus agreement			$ 250,000
Natural Gas [Member]
Related Party Transaction [Line Items]
Affiliate throughput percent			38.00%	36.00%	39.00%
Crude Oil, NGLs, and Produced Water [Member]
Related Party Transaction [Line Items]
Affiliate throughput percent			83.00%	85.00%	81.00%
Affiliates [Member]
Related Party Transaction [Line Items]
Administrative services fee under the omnibus agreement			$ 101,485,000	$ 49,672,000	$ 43,221,000
Materials and supplies inventory			18,400,000
Affiliates [Member] | Commodity-Price Swap Agreement [Member]
Related Party Transaction [Line Items]
Net gains (losses) on commodity-price swap agreements			(700,000)	(7,900,000)	600,000
Affiliates [Member] | Level-2 Inputs [Member] | Valuation, Market Approach [Member]
Related Party Transaction [Line Items]
Fair value of the note receivable			$ 337,700,000	279,600,000
Independent Director [Member] | Long-Term Incentive Plans [Member]
Related Party Transaction [Line Items]
Units vesting period			1 year
WES Operating [Member]
Related Party Transaction [Line Items]
Note receivable - Anadarko			$ 260,000,000	260,000,000
Capital contribution for the above-market component of swap agreements with Anadarko	[3]		7,407,000	51,618,000	58,551,000
Administrative services fee under the omnibus agreement	[4]		107,772,000	63,166,000	51,077,000
Materials and supplies inventory			23,444,000	9,665,000
WES Operating [Member] | Affiliates [Member]
Related Party Transaction [Line Items]
Note receivable - Anadarko		$ 260,000,000.0
Fixed annual rate for note receivable bearing interest		6.50%
Administrative services fee under the omnibus agreement			$ 99,613,000	$ 48,819,000	$ 42,411,000

[1] See Note 6.

[2] Cost of product includes product purchases from affiliates (as defined in Note 1) of $254.8 million, $168.5 million, and $74.6 million for the years ended December 31, 2019, 2018, and 2017, respectively. Operation and maintenance includes charges from affiliates of $147.0 million, $115.9 million, and $82.2 million for the years ended December 31, 2019, 2018, and 2017, respectively. General and administrative includes charges from affiliates of $101.5 million, $49.7 million, and $43.2 million for the years ended December 31, 2019, 2018, and 2017, respectively. See Note 6.

[3] See Note 6.

[4] Cost of product includes product purchases from affiliates (as defined in Note 1) of $254.8 million, $168.5 million, and $74.6 million for the years ended December 31, 2019, 2018, and 2017, respectively. Operation and maintenance includes charges from affiliates of $147.0 million, $115.9 million, and $82.2 million for the years ended December 31, 2019, 2018, and 2017, respectively. General and administrative includes charges from affiliates of $99.6 million, $48.8 million, and $42.4 million for the years ended December 31, 2019, 2018, and 2017, respectively. See Note 6.