Loans and allowance for loan losses (3) (Details) (USD $)
Jun. 30, 2012
Dec. 31, 2011
With no related allowance recorded [Abstract]    
Recorded investment $ 47,438,036 $ 34,623,937
Unpaid principal balance 55,618,658 36,856,805
With an allowance recorded [Abstract]    
Recorded investment 25,016,341 32,935,362,000
Unpaid principal balance 28,034,431 34,504,362,000
Related allowance 6,136,977 8,795,046,000
Total [Abstract]    
Recorded investment 72,454,377 67,559,299,000
Unpaid principal balance 83,653,089 71,361,167,000
Related Allowance 6,136,977 8,795,046,000
Commercial [Member]
   
With no related allowance recorded [Abstract]    
Recorded investment 15,051,292 9,722,132
Unpaid principal balance 19,436,447 11,094,408
With an allowance recorded [Abstract]    
Recorded investment 6,509,162 14,885,541,000
Unpaid principal balance 8,711,930 15,785,541,000
Related allowance 1,133,647 3,913,820,000
Total [Abstract]    
Recorded investment 21,560,454 24,607,673,000
Unpaid principal balance 28,148,377 26,879,949,000
Related Allowance 1,133,647 3,913,820,000
Residential [Member]
   
With no related allowance recorded [Abstract]    
Recorded investment 489,503 624,651
Unpaid principal balance 978,503 712,243
With an allowance recorded [Abstract]    
Recorded investment 0 587,235,000
Unpaid principal balance 0 587,235,000
Related allowance 0 320,250,000
Total [Abstract]    
Recorded investment 489,503 1,211,886,000
Unpaid principal balance 978,503 1,299,478,000
Related Allowance 0 320,250,000
Total construction and land development [Member]
   
With no related allowance recorded [Abstract]    
Recorded investment 15,540,795 10,346,783
Unpaid principal balance 20,414,950 11,806,651
With an allowance recorded [Abstract]    
Recorded investment 6,509,162 15,472,776,000
Unpaid principal balance 8,711,930 16,372,776,000
Related allowance 1,133,647 4,234,070,000
Total [Abstract]    
Recorded investment 22,049,957 25,819,559,000
Unpaid principal balance 29,126,880 28,179,427,000
Related Allowance 1,133,647 4,234,070,000
Farmland [Member]
   
With no related allowance recorded [Abstract]    
Recorded investment 1,049,489 0
Unpaid principal balance 1,049,489  
With an allowance recorded [Abstract]    
Recorded investment   0
Total [Abstract]    
Recorded investment 1,049,489 0
Unpaid principal balance 1,049,489 0
Related Allowance 0 0
Commercial real estate - owner occupied [Member]
   
With no related allowance recorded [Abstract]    
Recorded investment 6,872,799 6,414,362
Unpaid principal balance 6,903,383 6,414,362
With an allowance recorded [Abstract]    
Recorded investment 7,020,688 9,508,393,000
Unpaid principal balance 7,277,790 9,652,393,000
Related allowance 1,852,684 2,031,740,000
Total [Abstract]    
Recorded investment 13,893,487 15,922,755,000
Unpaid principal balance 14,181,173 16,066,755,000
Related Allowance 1,852,684 2,031,740,000
Commercial real estate - non-owner occupied [Member]
   
With no related allowance recorded [Abstract]    
Recorded investment 8,374,527 7,146,531
Unpaid principal balance 8,549,256 7,146,531
With an allowance recorded [Abstract]    
Recorded investment 5,008,676 1,719,690,000
Unpaid principal balance 5,008,676 1,719,690,000
Related allowance 1,338,605 450,000,000
Total [Abstract]    
Recorded investment 13,383,203 8,866,221,000
Unpaid principal balance 13,557,932 8,866,221,000
Related Allowance 1,338,605 450,000,000
Multifamily [Member]
   
With no related allowance recorded [Abstract]    
Recorded investment 941,632 2,019,675
Unpaid principal balance 941,632 2,019,675
With an allowance recorded [Abstract]    
Recorded investment 0 0
Unpaid principal balance 0 0
Related allowance 0 0
Total [Abstract]    
Recorded investment 941,632 2,019,675,000
Unpaid principal balance 941,632 2,019,675,000
Related Allowance 0 0
Total commercial real estate [Member]
   
With no related allowance recorded [Abstract]    
Recorded investment 17,238,447 15,580,568
Unpaid principal balance 17,443,760 15,580,568
With an allowance recorded [Abstract]    
Recorded investment 12,029,364 11,228,083,000
Unpaid principal balance 12,286,466 11,372,083,000
Related allowance 3,191,289 2,481,740,000
Total [Abstract]    
Recorded investment 29,267,811 26,808,651,000
Unpaid principal balance 29,730,226 26,952,651,000
Related Allowance 3,191,289 2,481,740,000
Home equity lines [Member]
   
With no related allowance recorded [Abstract]    
Recorded investment 1,725,387 702,338
Unpaid principal balance 1,887,187 702,338
With an allowance recorded [Abstract]    
Recorded investment 418,936 756,892,000
Unpaid principal balance 467,220 756,892,000
Related allowance 154,665 233,606,000
Total [Abstract]    
Recorded investment 2,144,323 1,459,230,000
Unpaid principal balance 2,354,407 1,459,230,000
Related Allowance 154,665 233,606,000
Secured by 1-4 family residential, secured by first deeds of trust [Member]
   
With no related allowance recorded [Abstract]    
Recorded investment 10,988,639 6,319,837
Unpaid principal balance 13,033,493 6,792,837
With an allowance recorded [Abstract]    
Recorded investment 4,426,370 4,224,325,000
Unpaid principal balance 4,598,717 4,749,325,000
Related allowance 719,908 1,007,155,000
Total [Abstract]    
Recorded investment 15,415,009 10,544,162,000
Unpaid principal balance 17,632,210 11,542,162,000
Related Allowance 719,908 1,007,155,000
Secured by 1-4 family residential, secured by second deeds of trust [Member]
   
With no related allowance recorded [Abstract]    
Recorded investment 836,754 336,257
Unpaid principal balance 1,012,754 336,257
With an allowance recorded [Abstract]    
Recorded investment 117,322 167,523,000
Unpaid principal balance 117,322 167,523,000
Related allowance 105,997 119,524,000
Total [Abstract]    
Recorded investment 954,076 503,780,000
Unpaid principal balance 1,130,076 503,780,000
Related Allowance 105,997 119,524,000
Total consumer real estate [Member]
   
With no related allowance recorded [Abstract]    
Recorded investment 13,550,780 7,358,432
Unpaid principal balance 15,933,434 7,831,432
With an allowance recorded [Abstract]    
Recorded investment 4,962,628 5,148,740,000
Unpaid principal balance 5,183,259 5,673,740,000
Related allowance 980,570 1,360,285,000
Total [Abstract]    
Recorded investment 18,513,408 12,507,172,000
Unpaid principal balance 21,116,693 13,505,172,000
Related Allowance 980,570 1,360,285,000
Commercial and industrial loans (except those secured by real estate) [Member]
   
With no related allowance recorded [Abstract]    
Recorded investment 1,071,027 1,194,913
Unpaid principal balance 1,789,527 1,494,913
With an allowance recorded [Abstract]    
Recorded investment 1,515,187 818,597,000
Unpaid principal balance 1,852,776 818,597,000
Related allowance 831,471 452,773,000
Total [Abstract]    
Recorded investment 2,586,214 2,013,510,000
Unpaid principal balance 3,642,303 2,313,510,000
Related Allowance 831,471 452,773,000
Consumer and other [Member]
   
With no related allowance recorded [Abstract]    
Recorded investment 36,987 143,241
Unpaid principal balance 36,987 143,241
With an allowance recorded [Abstract]    
Recorded investment 0 267,166,000
Unpaid principal balance 0 267,166,000
Related allowance 0 266,178,000
Total [Abstract]    
Recorded investment 36,987 410,407,000
Unpaid principal balance 36,987 410,407,000
Related Allowance $ 0 $ 266,178,000