XML 67 R49.htm IDEA: XBRL DOCUMENT v2.4.0.6
Estimated Quantities of Proved Reserves (Detail)
12 Months Ended
Dec. 31, 2012
bbl
Dec. 31, 2011
bbl
Proved reserves:    
Beginning 2,714,150 2,320,150
Revisions of previous estimates (193,059) (130,908)
Purchase of minerals in place 0 700,190
Extension and discoveries 502,751 316,049
Sale of minerals in place 0 (221,365)
Sales of Rantoul Partners interest   (198,187)
Production (96,842) (71,729)
Ending 2,927,000 2,714,150