Property, Plant and Equipment - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	[1]	Sep. 30, 2016	Sep. 30, 2015	[1]
Property, Plant and Equipment [Line Items]
Impairments	$ 2,392	$ 2,335		$ 11,313	$ 276,579
Western Gas Partners, LP [Member] | Newcastle System [Member]
Property, Plant and Equipment [Line Items]
Impairments				6,100
Western Gas Partners, LP [Member] | Newcastle System [Member] | Fair Value Measurements Nonrecurring [Member] | Level 3 Inputs [Member] | Income Approach Valuation Technique [Member]
Property, Plant and Equipment [Line Items]
Estimated fair value	$ 3,100			3,100
Western Gas Partners, LP [Member] | Equipment [Member]
Property, Plant and Equipment [Line Items]
Impairments				$ 5,200

[1] Financial information has been recast to include the financial position and results attributable to the Springfield interest. See Note 1 and Note 2.