SUBSEQUENT EVENTS: (Details) (USD $)	9 Months Ended				0 Months Ended	3 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 Senior secured revolving credit agreement	Oct. 30, 2012 Subsequent event Senior secured revolving credit agreement	Oct. 11, 2012 Subsequent event Liberty Energy, LLC	Sep. 30, 2012 Subsequent event Liberty Energy, LLC
SUBSEQUENT EVENTS
Non-operating interest in the Sargent field in California (as a percent)					50.00%
Sale amount					$ 3,200,000
Impairment recorded to write the field down to the expected sales price	1,916,690	4,067,023				460,000
Borrowing base			$ 245,000,000	$ 325,000,000