Asset Retirement Obligations (Tables)
 9 Months Ended
Sep. 30, 2012
Asset Retirement Obligation Disclosure [Abstract]  
Schedule of Change in Asset Retirement Obligation [Table Text Block]
Asset retirement obligations at December 31, 2011
$
1,593

Accretion
73

Revision in estimated cash flows
11

Liabilities incurred
14

Liabilities settled
(8
)
Asset retirement obligations at September 30, 2012
$
1,683