XML 51 R28.htm IDEA: XBRL DOCUMENT v2.4.0.8
Asset Retirement Obligations (Details) (USD $)
In Thousands, unless otherwise specified
3 Months Ended 6 Months Ended
Jun. 30, 2013
Jun. 30, 2012
Jun. 30, 2013
Jun. 30, 2012
Dec. 31, 2012
Changes in the Company's asset retirement obligations          
Beginning asset retirement obligations     $ 5,769    
Liabilities incurred during period     214    
Liabilities settled during period     (1)    
Revisions in estimated cash flows     542    
Accretion expense 80 58 161 111  
Ending asset retirement obligations 6,685   6,685    
Less: current asset retirement obligations (804) [1]   (804) [1]    
Long-term asset retirement obligations $ 5,881   $ 5,881   $ 5,109
[1] Included in accrued liabilities in the Company’s unaudited condensed consolidated balance sheet at June 30, 2013.