Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Related Party Transaction [Line Items]
U.S. federal tax reform	$ 0	$ 87,306	$ 0
Statutory tax rate	0.00%	0.00%	0.00%
Credit carryforwards	$ 497	$ 448
Tax credit carryforward, expiration date	Dec. 31, 2026
Anadarko Midstream Assets [Member]
Related Party Transaction [Line Items]
U.S. federal tax reform		$ 87,306
Statutory tax rate	21.00%	35.00%

Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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-Name Accounting Standards Codification
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The amount of the tax credit carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.

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Expiration date of the tax credit carryforward, in CCYY-MM-DD format.

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Effective Income Tax Rate Reconciliation,Tax Cuts and Jobs Act of 2017, Amount

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