Related party transactions (Tables)
 6 Months Ended
Jun. 30, 2012
AFS and/ or Affiliates Earned Fees, Commissions, and Billed for Reimbursements Pursuant to Operating Agreement

During the three and six months ended June 30, 2012 and 2011, AFS and/or affiliates earned fees and commissions, and billed for reimbursements, pursuant to the Operating Agreement as follows (in thousands):

       
  Three Months Ended June 30,   Six Months Ended June 30,
     2012   2011   2012   2011
Asset management fees to Managing Member   $        40     $        48     $        89     $          92  
Cost reimbursements to Managing Member     73       —       289       679  
     $ 113     $ 48     $ 378     $ 771