Commitments and Contingencies - Additional Information (Details) - Western Gas Partners, LP [Member] - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Loss Contingencies [Line Items]
Committed capital	$ 42.0		$ 42.0
Rent expense associated with office, warehouse and equipment leases	$ 4.9	$ 2.4	$ 13.6	$ 6.8

Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the next rolling twelve months following the latest balance sheet. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

No definition available.

Name:	us-gaap_UnrecordedUnconditionalPurchaseObligationDueInNextRollingTwelveMonths
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant