Asset Aquisition (PPA Operating Expense) (Details) (Clearfield Energy [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012
Clearfield Energy [Member]
Business Acquisition [Line Items]
Post Acquisition Oil And Gas Revenue	$ 108.0
Post Acquisition Operating Costs	$ 94.2

Generally recurring costs associated with normal operations except for the portion of these expenses which can be clearly related to production and included in cost of sales or services. Includes selling, general and administrative expense and related to acquisition during the period.

No definition available.

Name:	xtxi_PostAcquisitionOperatingCosts
Namespace Prefix:	xtxi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration