Annual report pursuant to Section 13 and 15(d)

Summary Of Significant Accounting Policies (Narrative) (Details)

v2.4.0.6
Summary Of Significant Accounting Policies (Narrative) (Details) (USD $)
12 Months Ended
Dec. 31, 2012
purchaser
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Summary Of Significant Accounting Policies [Line Items]        
Number Of Purchasers 2      
Accounts receivable, collection period 30 days      
Conversion ratio, gas to barrels of oil 6      
Capitalized costs of oil and natural gas properties excluded from amortization $ 626,295,000 $ 138,623,000    
Gas balancing payable 354,000 0    
Cumulative transaltion adjustment $ 2,442,000 $ 1,087,000 $ 2,952,000 $ 696,000
Minimum [Member]
       
Summary Of Significant Accounting Policies [Line Items]        
Useful life 3 years      
Maximum [Member]
       
Summary Of Significant Accounting Policies [Line Items]        
Useful life 30 years