Commitments and Contingencies - Additional Information (Details) - Western Gas Partners, LP [Member] - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Loss Contingencies [Line Items]
Committed capital	$ 143.3		$ 143.3
Rent expense associated with office, warehouse and equipment leases	$ 11.3	$ 8.9	$ 30.7	$ 26.2

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