Basis Of Presentation Basis of Presentation (Equity - Additional Paid in Capital) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
Jun. 30, 2012
Subsidiary or Equity Method Investee [Line Items]
Deferred tax provision attributable to 2008 Pioneer Southwest initial public offering	$ (49,072)
Pioneer Southwest Ltip [Member]
Subsidiary or Equity Method Investee [Line Items]
Deferred tax provision attributable to 2008 Pioneer Southwest initial public offering	$ (49,072)

The amount provided for deferred income taxes in relation to any gain (loss) recognized in income of the entity resulting from the issuance of shares by a subsidiary or equity method investee.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 5

-Section H

-Paragraph Question 6

Name:	us-gaap_SubsidiaryOrEquityMethodInvesteeDeferredIncomeTaxProvisionOnCumulativeGainLossRecognizedAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration