Property, Plant and Equipment Table (details) (USD $) In Thousands, unless otherwise specified								3 Months Ended				3 Months Ended						3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012		Mar. 31, 2013 Land Member Western Gas Partners [Member]	Dec. 31, 2012 Land Member Western Gas Partners [Member]	Mar. 31, 2013 Gas Gathering And Processing Equipment Member Western Gas Partners [Member]	Dec. 31, 2012 Gas Gathering And Processing Equipment Member Western Gas Partners [Member]	Mar. 31, 2013 Gas Gathering And Processing Equipment Member Minimum [Member] Western Gas Partners [Member]	Mar. 31, 2013 Gas Gathering And Processing Equipment Member Maximum [Member] Western Gas Partners [Member]	Mar. 31, 2013 Pipelines And Equipment [Member] Western Gas Partners [Member]	Dec. 31, 2012 Pipelines And Equipment [Member] Western Gas Partners [Member]	Mar. 31, 2013 Pipelines And Equipment [Member] Minimum [Member] Western Gas Partners [Member]	Mar. 31, 2013 Pipelines And Equipment [Member] Maximum [Member] Western Gas Partners [Member]	Mar. 31, 2013 Asset Under Construction Member Western Gas Partners [Member]	Dec. 31, 2012 Asset Under Construction Member Western Gas Partners [Member]	Mar. 31, 2013 Other Capitalized Property Plant And Equipment Member Western Gas Partners [Member]	Dec. 31, 2012 Other Capitalized Property Plant And Equipment Member Western Gas Partners [Member]	Mar. 31, 2013 Other Capitalized Property Plant And Equipment Member Minimum [Member] Western Gas Partners [Member]	Mar. 31, 2013 Other Capitalized Property Plant And Equipment Member Maximum [Member] Western Gas Partners [Member]
Property Plant And Equipment Line Items
Property, plant and equipment	$ 3,733,690	$ 3,432,392	[1]	$ 501	$ 501	$ 3,158,042	$ 2,911,572			$ 91,542	$ 91,126			$ 472,227	$ 422,002	$ 11,378	$ 7,191
Accumulated depreciation	745,477	714,436	[1]
Net property, plant and equipment	$ 2,988,213	$ 2,717,956	[1]
Estimated useful life								3 years	47 years			15 years	45 years					3 years	25 years

[1] Financial information has been recast to include the financial position and results attributable to the Non-Operated Marcellus Interest. See Note 2.