Income Taxes - Tax Rate Reconciliation Table (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Related Party Transaction [Line Items]
Income (loss) before income taxes	$ 451,458	$ 578,068	$ 605,352
Statutory tax rate	0.00%	0.00%	0.00%
Adjustments resulting from:
Federal taxes on income	$ 0	$ 0	$ 0
State taxes on income (net of federal benefit) and Texas margin tax expense (benefit)	2,946	4,866	2,093
Income tax expense (benefit)	$ 2,946	$ 4,866	$ 8,372
Effective tax rate	1.00%	1.00%	1.00%
Western Gas Partners, LP [Member]
Adjustments resulting from:
Federal taxes on income	$ 0	$ 0	$ 6,162
State taxes on income (net of federal benefit) and Texas margin tax expense (benefit)	$ 0	$ 0	$ 117

Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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