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Allowance for Probable Loan Losses (Aging By Loan Class) (Details) - USD ($) | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
--- | --- | --- | ---
Financing receivable recorded investment |  |  |
Past due | $ 77,053,000 | $ 61,400,000 |
Past due 90 days or Greater and Still Accruing | 7,257,000 | 5,226,000 | $ 11,616,000
Loans, current | 6,271,119,000 | 5,903,288,000 |
Total loans | 6,348,172,000 | 5,964,688,000 |
30 to 59 Days |  |  |
Financing receivable recorded investment |  |  |
Past due | 15,855,000 | 17,299,000 |
60 to 89 Days |  |  |
Financing receivable recorded investment |  |  |
Past due | 4,429,000 | 6,327,000 |
90 Days or Greater |  |  |
Financing receivable recorded investment |  |  |
Past due | 56,769,000 | 37,774,000 |
Commercial |  |  |
Financing receivable recorded investment |  |  |
Past due | 22,496,000 | 26,033,000 |
Past due 90 days or Greater and Still Accruing | 537,000 | 392,000 |
Loans, current | 1,063,971,000 | 883,634,000 |
Total loans | 1,086,467,000 | 909,667,000 |
Commercial | 30 to 59 Days |  |  |
Financing receivable recorded investment |  |  |
Past due | 3,790,000 | 4,081,000 |
Commercial | 60 to 89 Days |  |  |
Financing receivable recorded investment |  |  |
Past due | 398,000 | 829,000 |
Commercial | 90 Days or Greater |  |  |
Financing receivable recorded investment |  |  |
Past due | 18,308,000 | 21,123,000 |
Commercial Real Estate: Other Construction and Land Development |  |  |
Financing receivable recorded investment |  |  |
Past due | 1,482,000 | 6,354,000 |
Past due 90 days or Greater and Still Accruing | 6,000 | 9,000 |
Loans, current | 1,682,068,000 | 1,710,521,000 |
Total loans | 1,683,550,000 | 1,716,875,000 |
Commercial Real Estate: Other Construction and Land Development | 30 to 59 Days |  |  |
Financing receivable recorded investment |  |  |
Past due | 354,000 | 1,502,000 |
Commercial Real Estate: Other Construction and Land Development | 60 to 89 Days |  |  |
Financing receivable recorded investment |  |  |
Past due | 308,000 | 396,000 |
Commercial Real Estate: Other Construction and Land Development | 90 Days or Greater |  |  |
Financing receivable recorded investment |  |  |
Past due | 820,000 | 4,456,000 |
Commercial Real Estate: Farmland & Commercial |  |  |
Financing receivable recorded investment |  |  |
Past due | 35,576,000 | 12,658,000 |
Past due 90 days or Greater and Still Accruing | 954,000 | 289,000 |
Loans, current | 2,007,709,000 | 1,930,412,000 |
Total loans | 2,043,285,000 | 1,943,070,000 |
Commercial Real Estate: Farmland & Commercial | 30 to 59 Days |  |  |
Financing receivable recorded investment |  |  |
Past due | 3,925,000 | 3,454,000 |
Commercial Real Estate: Farmland & Commercial | 60 to 89 Days |  |  |
Financing receivable recorded investment |  |  |
Past due | 518,000 | 3,054,000 |
Commercial Real Estate: Farmland & Commercial | 90 Days or Greater |  |  |
Financing receivable recorded investment |  |  |
Past due | 31,133,000 | 6,150,000 |
Commercial Real Estate: Multifamily |  |  |
Financing receivable recorded investment |  |  |
Past due | 560,000 | 596,000 |
Loans, current | 192,356,000 | 139,870,000 |
Total loans | 192,916,000 | 140,466,000 |
Commercial Real Estate: Multifamily | 30 to 59 Days |  |  |
Financing receivable recorded investment |  |  |
Past due | 84,000 | 44,000 |
Commercial Real Estate: Multifamily | 90 Days or Greater |  |  |
Financing receivable recorded investment |  |  |
Past due | 476,000 | 552,000 |
Residential First Lien |  |  |
Financing receivable recorded investment |  |  |
Past due | 10,848,000 | 11,108,000 |
Past due 90 days or Greater and Still Accruing | 3,861,000 | 3,756,000 |
Loans, current | 421,929,000 | 410,796,000 |
Total loans | 432,777,000 | 421,904,000 |
Residential First Lien | 30 to 59 Days |  |  |
Financing receivable recorded investment |  |  |
Past due | 4,295,000 | 5,615,000 |
Residential First Lien | 60 to 89 Days |  |  |
Financing receivable recorded investment |  |  |
Past due | 2,458,000 | 1,350,000 |
Residential First Lien | 90 Days or Greater |  |  |
Financing receivable recorded investment |  |  |
Past due | 4,095,000 | 4,143,000 |
Residential Junior Lien |  |  |
Financing receivable recorded investment |  |  |
Past due | 3,000,000 | 1,480,000 |
Past due 90 days or Greater and Still Accruing | 1,099,000 | 382,000 |
Loans, current | 697,748,000 | 608,838,000 |
Total loans | 700,748,000 | 610,318,000 |
Residential Junior Lien | 30 to 59 Days |  |  |
Financing receivable recorded investment |  |  |
Past due | 1,310,000 | 762,000 |
Residential Junior Lien | 60 to 89 Days |  |  |
Financing receivable recorded investment |  |  |
Past due | 580,000 | 178,000 |
Residential Junior Lien | 90 Days or Greater |  |  |
Financing receivable recorded investment |  |  |
Past due | 1,110,000 | 540,000 |
Consumer |  |  |
Financing receivable recorded investment |  |  |
Past due | 1,126,000 | 1,418,000 |
Past due 90 days or Greater and Still Accruing | 133,000 | 387,000 |
Loans, current | 48,417,000 | 53,750,000 |
Total loans | 49,543,000 | 55,168,000 |
Consumer | 30 to 59 Days |  |  |
Financing receivable recorded investment |  |  |
Past due | 868,000 | 910,000 |
Consumer | 60 to 89 Days |  |  |
Financing receivable recorded investment |  |  |
Past due | 98,000 | 95,000 |
Consumer | 90 Days or Greater |  |  |
Financing receivable recorded investment |  |  |
Past due | 160,000 | 413,000 |
Foreign |  |  |
Financing receivable recorded investment |  |  |
Past due | 1,965,000 | 1,753,000 |
Past due 90 days or Greater and Still Accruing | 667,000 | 11,000 |
Loans, current | 156,921,000 | 165,467,000 |
Total loans | 158,886,000 | 167,220,000 |
Foreign | 30 to 59 Days |  |  |
Financing receivable recorded investment |  |  |
Past due | 1,229,000 | 931,000 |
Foreign | 60 to 89 Days |  |  |
Financing receivable recorded investment |  |  |
Past due | 69,000 | 425,000 |
Foreign | 90 Days or Greater |  |  |
Financing receivable recorded investment |  |  |
Past due | $ 667,000 | $ 397,000 |

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