Contingencies (Details 2) (Acreage in the Eagle Ford shale play in South Texas, USD $)	1 Months Ended	12 Months Ended
Feb. 28, 2011	Dec. 31, 2011 A
Acreage in the Eagle Ford shale play in South Texas
Litigations
Percentage of overriding royalty interest in production (as a percent)		7.46875%
Acres of land for which an overriding royalty interest is claimed (in acres)		22,000
Damages sought value (in dollars)	$ 5,100,000

The value (monetary amount) of the award the plaintiff seeks in the legal matter.

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