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Decommissioning and Other Asset Retirement Obligations (Details) (USD $)
3 Months Ended
Mar. 31, 2014
Dec. 31, 2013
Decommissioning and Other Asset Retirement Obligations Detail [Table]    
Beginning balance for the period, as reported $ 50,904,000  
Activity in the period:    
Accretion of liability 190,000  
Revisions in estimated cash flows 9,380,000  
Settlement of retirement obligations (13,307,000)  
Ending balance as of March 31 47,167,000  
Fair value of asset retirement obligations associated with non-operated properties $ 7,800,000 $ 7,600,000