Asset Acquisitions (Proforma) (Details) (Clearfield Energy, USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011
Clearfield Energy
Business Acquisition [Line Items]
Pro forma total revenues	$ 1,897,199	$ 2,266,868
Pro forma net loss	(39,021)	(15,476)
Business Acquisitions Pro Forma Income Loss Attributable To Parent	$ (14,762)	$ (8,460)
Basic and Diluted	$ (0.30)	$ (0.18)

Name:	us-gaap_BusinessAcquisitionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

The pro forma basic net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (h)(2)-(3)

-URI http://asc.fasb.org/extlink&oid=25497992&loc=d3e1392-128463

+ Details

Name:	us-gaap_BusinessAcquisitionProFormaEarningsPerShareBasic
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.

+ References

+ Details

Name:	us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period.

+ References

+ Details

Name:	us-gaap_BusinessAcquisitionsProFormaRevenue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.

+ References

No definition available.

+ Details

Name:	xtxi_BusinessAcquisitionsProFormaIncomeLossAttributableToParent
Namespace Prefix:	xtxi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration