Income Taxes Income Taxes - Tax Rate Reconciliation Table (details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Related Party Transaction [Line Items]
Income before income taxes	$ 284,967	$ 169,510	$ 239,011
Statutory tax rate	0.00%	0.00%	0.00%
Non-deductible expense	0	0	1,484
Adjustments Resulting From [Abstract]
State taxes on income attributable to Partnership assets pre-acquisition (net of federal benefit) Texas margin tax expense (benefit)	(1,359)	1,258	664
Total income tax expense	2,580	48,909	58,796
Effective tax rate	1.00%	29.00%	25.00%
Pre Acquisition From Parent [Member]
Adjustments Resulting From [Abstract]
Federal taxes on income attributable to Partnership assets pre-acquisition	0	0	29,502
State taxes on income attributable to Partnership assets pre-acquisition (net of federal benefit) Texas margin tax expense (benefit)	0	0	1,984
Western Gas Partners [Member]
Adjustments Resulting From [Abstract]
Federal taxes on income attributable to Partnership assets pre-acquisition	3,318	41,582	23,872
State taxes on income attributable to Partnership assets pre-acquisition (net of federal benefit) Texas margin tax expense (benefit)	$ 621	$ 6,069	$ 1,290