Income Taxes - Tax Rate Reconciliation Table (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Related Party Transaction [Line Items]
Income (loss) before income taxes	$ 605,352	$ 56,630	$ 492,550
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)	2,093	2,411	2,481
Income tax expense (benefit)	$ 8,372	$ 45,532	$ 39,061
Effective tax rate	1.00%	80.00%	8.00%
Change in deferred state income taxes		$ 2,200
Change in Texas margin tax rates		0.25%
Western Gas Partners, LP [Member]
Adjustments resulting from:
Federal taxes on income	$ 6,162	$ 42,823	$ 35,716
State taxes on income (net of federal benefit) and Texas margin tax expense (benefit)	$ 117	$ 298	$ 864

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

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