Commitments and contingencies (Tables)
9 Months Ended
Sep. 30, 2012
Commitments and contingencies [Abstract]  
Summary of outstanding off-balance sheet financial instruments
The Company had outstanding the following approximate off-balance-sheet financial instruments whose contract amounts represent credit risk at the dates indicated:

   
September 30,
  
December 31,
 
   
2012
  
2011
 
        
Undisbursed credit lines
 $34,947,000  $40,661,000 
Commitments to extend or originate credit
  35,834,000   18,214,000 
Standby letter of credit
  2,774,000   3,719,000 
          
Total commitments to extend credit
 $73,555,000  $62,594,000