XML 34 R73.htm IDEA: XBRL DOCUMENT v2.4.0.8
Asset Retirement Obligations (Schedule Of Change In Asset Retirement Obligation) (Details) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Asset Retirement Obligations [Abstract]      
Asset retirement obligations, Beginning balance $ 126,991 $ 92,561  
Asset retirement obligations, Assumed in acquisition 13,409 14,581  
Asset retirement obligations, Revisions to previous estimates 12,911 [1] 17,278 [1]  
Asset retirement obligations, Liabilities incurred 360 1,185  
Asset retirement obligations, Liabilities settled (5,806) (4,262)  
Asset retirement obligations, Accretion expense 7,456 5,648 4,593
Asset retirement obligations, Ending balance 155,321 126,991 92,561
Less: Current portion of asset retirement obligations 4,310 1,426  
Asset retirement obligations - non-current $ 151,011 $ 125,565  
[1] In 2013 and 2012, we recorded an upward revision to previous estimates for our asset retirement obligations primarily due to changes in the estimated abandonment dates.