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Allowance for Probable Loan Losses (Details 4) (USD $) | 12 Months Ended
--- | ---
Dec. 31, 2011 D | Dec. 31, 2010 | Dec. 31, 2009
Loan loss allowances, impaired financing receivable |  |  |
Recorded Investment |  |  | $ 118,274,000
Related Allowance |  |  | 30,555,000
Average Recorded Investment | 142,310,000 | 130,481,000 | 149,528,000
Period of charge off for past due unsecured commercial loans (in days) | 90 |  |
Loans with Related Allowance |  |  |
Loan loss allowances, impaired financing receivable |  |  |
Recorded Investment | 87,369,000 | 51,506,000 | 106,780,000
Unpaid Principal Balance | 87,419,000 | 51,594,000 |
Related Allowance | 27,252,000 | 12,171,000 |
Average Recorded Investment | 87,951,000 | 52,193,000 |
Interest Recognized | 858,000 | 902,000 |
Loans with No Related Allowance |  |  |
Loan loss allowances, impaired financing receivable |  |  |
Recorded Investment | 48,936,000 | 73,694,000 | 11,494,000
Unpaid Principal Balance | 51,423,000 | 76,236,000 |
Average Recorded Investment | 54,359,000 | 78,288,000 |
Interest Recognized | 399,000 | 32,000 |
Commercial | Loans with Related Allowance |  |  |
Loan loss allowances, impaired financing receivable |  |  |
Recorded Investment | 24,108,000 | 23,062,000 |
Unpaid Principal Balance | 24,108,000 | 23,071,000 |
Related Allowance | 14,402,000 | 8,138,000 |
Average Recorded Investment | 24,145,000 | 23,096,000 |
Interest Recognized | 41,000 | 42,000 |
Commercial | Loans with No Related Allowance |  |  |
Loan loss allowances, impaired financing receivable |  |  |
Recorded Investment | 3,495,000 | 364,000 |
Unpaid Principal Balance | 3,932,000 | 980,000 |
Average Recorded Investment | 3,942,000 | 993,000 |
Interest Recognized | 20,000 | 30,000 |
Commercial real estate: other construction and land development | Loans with Related Allowance |  |  |
Loan loss allowances, impaired financing receivable |  |  |
Recorded Investment | 34,417,000 | 10,603,000 |
Unpaid Principal Balance | 34,432,000 | 10,645,000 |
Related Allowance | 3,073,000 | 592,000 |
Average Recorded Investment | 34,709,000 | 10,622,000 |
Commercial real estate: other construction and land development | Loans with No Related Allowance |  |  |
Loan loss allowances, impaired financing receivable |  |  |
Recorded Investment | 26,011,000 | 66,604,000 |
Unpaid Principal Balance | 26,112,000 | 66,755,000 |
Average Recorded Investment | 27,722,000 | 68,608,000 |
Interest Recognized | 128,000 | 2,000 |
Commercial real estate: farmland and commercial | Loans with Related Allowance |  |  |
Loan loss allowances, impaired financing receivable |  |  |
Recorded Investment | 28,636,000 | 17,841,000 |
Unpaid Principal Balance | 28,671,000 | 17,878,000 |
Related Allowance | 9,754,000 | 3,441,000 |
Average Recorded Investment | 28,883,000 | 18,475,000 |
Interest Recognized | 817,000 | 860,000 |
Commercial real estate: farmland and commercial | Loans with No Related Allowance |  |  |
Loan loss allowances, impaired financing receivable |  |  |
Recorded Investment | 13,595,000 | 4,003,000 |
Unpaid Principal Balance | 15,394,000 | 5,606,000 |
Average Recorded Investment | 16,271,000 | 5,594,000 |
Interest Recognized | 102,000 |  |
Commercial real estate: multifamily | Loans with No Related Allowance |  |  |
Loan loss allowances, impaired financing receivable |  |  |
Recorded Investment | 411,000 | 473,000 |
Unpaid Principal Balance | 411,000 | 473,000 |
Average Recorded Investment | 439,000 | 500,000 |
Residential: first lien | Loans with Related Allowance |  |  |
Loan loss allowances, impaired financing receivable |  |  |
Recorded Investment | 208,000 |  |
Unpaid Principal Balance | 208,000 |  |
Related Allowance | 23,000 |  |
Average Recorded Investment | 214,000 |  |
Residential: first lien | Loans with No Related Allowance |  |  |
Loan loss allowances, impaired financing receivable |  |  |
Recorded Investment | 2,082,000 | 2,015,000 |
Unpaid Principal Balance | 2,220,000 | 2,143,000 |
Average Recorded Investment | 2,230,000 | 2,297,000 |
Interest Recognized | 27,000 |  |
Residential: junior lien | Loans with No Related Allowance |  |  |
Loan loss allowances, impaired financing receivable |  |  |
Recorded Investment | 1,962,000 | 199,000 |
Unpaid Principal Balance | 1,970,000 | 226,000 |
Average Recorded Investment | 1,980,000 | 228,000 |
Interest Recognized | 118,000 |  |
Consumer | Loans with No Related Allowance |  |  |
Loan loss allowances, impaired financing receivable |  |  |
Recorded Investment | 1,334,000 | 29,000 |
Unpaid Principal Balance | 1,338,000 | 46,000 |
Average Recorded Investment | 1,729,000 | 49,000 |
Foreign | Loans with No Related Allowance |  |  |
Loan loss allowances, impaired financing receivable |  |  |
Recorded Investment | 46,000 | 7,000 |
Unpaid Principal Balance | 46,000 | 7,000 |
Average Recorded Investment | 46,000 | 19,000 |
Interest Recognized | $ 4,000 |  |

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