XML 64 R53.htm IDEA: XBRL DOCUMENT v2.4.0.6
Property And Equipment (Summary of Unevaluated Properties Excluded from Amortization) (Details 1) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Summary of unevaluated properties excluded from oil and natural gas properties being amortized        
Property acquisition costs $ 110,658 $ 12,543 $ 351,712 $ 115,075
Exploration and development 106,075 40,152 3,155 8,390
Capitalized interest 29,249 30,430 333 1,382
Total 245,982 83,125 355,200 124,847
Property acquisition costs 589,988      
Exploration and development 157,772      
Capitalized interest 61,394      
Total $ 809,154 $ 1,157,106