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Allowance for Probable Loan Losses (Impaired Loans) (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended | 12 Months Ended
--- | --- | --- | ---
Sep. 30, 2016 | Sep. 30, 2015 | Sep. 30, 2016 | Sep. 30, 2015 | Dec. 31, 2015
Interest Recognized |  |  |  |  |
Total trouble debt restructuring | $ 24,823 |  | $ 24,823 |  | $ 15,719
Period of charge off for past due unsecured commercial loans |  |  | 90 days |  |
Class of Financing Receivable |  |  |  |  |
Recorded investment: |  |  |  |  |
Total impaired loans with related allowance | 7,402 |  | $ 7,402 |  | 8,785
Total impaired loans with no related allowance | 40,189 |  | 40,189 |  | 51,663
Unpaid principal balance: |  |  |  |  |
Total impaired loans with an allowance recorded | 8,633 |  | 8,633 |  | 9,233
Total impaired loans with no related allowance recorded | 68,367 |  | 68,367 |  | 64,788
Related Allowance | 1,396 |  | 1,396 |  | 2,206
Average recorded investment: |  |  |  |  |
Total impaired loans with an allowance recorded | 7,442 | $ 14,934 | 9,040 | $ 20,816 | 33,286
Total impaired loans with no related allowance recorded | 33,532 | 42,643 | 36,577 | 43,580 | 42,643
Interest Recognized |  |  |  |  |
Total impaired loans with an allowance recorded | 24 | 23 | 73 | 69 | 92
Total impaired loans with no related allowance recorded | 109 | 106 | 338 | 318 | 106
Commercial |  |  |  |  |
Interest Recognized |  |  |  |  |
Total trouble debt restructuring | 11,754 |  | 11,754 |  | 2,419
Commercial | Class of Financing Receivable |  |  |  |  |
Recorded investment: |  |  |  |  |
Total impaired loans with related allowance | 2,214 |  | 2,214 |  | 4,016
Total impaired loans with no related allowance | 19,717 |  | 19,717 |  | 26,930
Unpaid principal balance: |  |  |  |  |
Total impaired loans with an allowance recorded | 2,293 |  | 2,293 |  | 4,156
Total impaired loans with no related allowance recorded | 46,729 |  | 46,729 |  | 38,845
Related Allowance | 734 |  | 734 |  | 1,704
Average recorded investment: |  |  |  |  |
Total impaired loans with an allowance recorded | 2,247 | 11,247 | 3,239 | 15,634 | 19,313
Total impaired loans with no related allowance recorded | 13,813 | 21,291 | 15,234 | 20,623 | 21,291
Interest Recognized |  |  |  |  |
Total impaired loans with no related allowance recorded | 1 | 1 | 3 | 3 | 1
Commercial Real Estate: Other Construction and Land Development |  |  |  |  |
Interest Recognized |  |  |  |  |
Total trouble debt restructuring | 1,585 |  | 1,585 |  | 2,553
Commercial Real Estate: Other Construction and Land Development | Class of Financing Receivable |  |  |  |  |
Recorded investment: |  |  |  |  |
Total impaired loans with related allowance | 158 |  | 158 |  | 167
Total impaired loans with no related allowance | 4,443 |  | 4,443 |  | 6,054
Unpaid principal balance: |  |  |  |  |
Total impaired loans with an allowance recorded | 169 |  | 169 |  | 169
Total impaired loans with no related allowance recorded | 4,457 |  | 4,457 |  | 6,204
Related Allowance | 116 |  | 116 |  | 100
Average recorded investment: |  |  |  |  |
Total impaired loans with an allowance recorded | 159 | 170 | 162 | 1,136 | 7,183
Total impaired loans with no related allowance recorded | 3,924 | 6,045 | 4,927 | 6,561 | 6,045
Interest Recognized |  |  |  |  |
Total impaired loans with no related allowance recorded | 14 | 20 | 53 | 57 | 20
Commercial Real Estate: Farmland & Commercial |  |  |  |  |
Interest Recognized |  |  |  |  |
Total trouble debt restructuring | 3,101 |  | 3,101 |  | 2,853
Commercial Real Estate: Farmland & Commercial | Class of Financing Receivable |  |  |  |  |
Recorded investment: |  |  |  |  |
Total impaired loans with related allowance | 5,030 |  | 5,030 |  | 4,003
Total impaired loans with no related allowance | 5,716 |  | 5,716 |  | 9,803
Unpaid principal balance: |  |  |  |  |
Total impaired loans with an allowance recorded | 6,171 |  | 6,171 |  | 4,309
Total impaired loans with no related allowance recorded | 6,751 |  | 6,751 |  | 10,717
Related Allowance | 546 |  | 546 |  | 202
Average recorded investment: |  |  |  |  |
Total impaired loans with an allowance recorded | 5,036 | 3,517 | 5,639 | 4,046 | 6,790
Total impaired loans with no related allowance recorded | 5,513 | 6,203 | 6,469 | 7,253 | 6,203
Interest Recognized |  |  |  |  |
Total impaired loans with an allowance recorded | 24 | 23 | 73 | 69 | 92
Total impaired loans with no related allowance recorded | 3 |  | 10 |  |
Commercial Real Estate: Multifamily | Class of Financing Receivable |  |  |  |  |
Recorded investment: |  |  |  |  |
Total impaired loans with related allowance |  |  |  |  | 599
Total impaired loans with no related allowance | 571 |  | 571 |  | 178
Unpaid principal balance: |  |  |  |  |
Total impaired loans with an allowance recorded |  |  |  |  | 599
Total impaired loans with no related allowance recorded | 576 |  | 576 |  | 178
Related Allowance |  |  |  |  | 200
Average recorded investment: |  |  |  |  |
Total impaired loans with no related allowance recorded | 577 | 819 | 349 | 832 | 819
Interest Recognized |  |  |  |  |
Total impaired loans with no related allowance recorded |  |  |  | 1 |
Residential First Lien |  |  |  |  |
Interest Recognized |  |  |  |  |
Total trouble debt restructuring | 5,960 |  | 5,960 |  | 5,316
Residential First Lien | Class of Financing Receivable |  |  |  |  |
Recorded investment: |  |  |  |  |
Total impaired loans with no related allowance | 6,752 |  | 6,752 |  | 5,699
Unpaid principal balance: |  |  |  |  |
Total impaired loans with no related allowance recorded | 6,840 |  | 6,840 |  | 5,822
Average recorded investment: |  |  |  |  |
Total impaired loans with no related allowance recorded | 6,712 | 5,315 | 6,644 | 5,375 | 5,315
Interest Recognized |  |  |  |  |
Total impaired loans with no related allowance recorded | 75 | 65 | 220 | 188 | 65
Residential Junior Lien |  |  |  |  |
Interest Recognized |  |  |  |  |
Total trouble debt restructuring | 830 |  | 830 |  | 929
Residential Junior Lien | Class of Financing Receivable |  |  |  |  |
Recorded investment: |  |  |  |  |
Total impaired loans with no related allowance | 1,008 |  | 1,008 |  | 950
Unpaid principal balance: |  |  |  |  |
Total impaired loans with no related allowance recorded | 1,032 |  | 1,032 |  | 972
Average recorded investment: |  |  |  |  |
Total impaired loans with no related allowance recorded | 1,012 | 1,075 | 1,011 | 1,255 | 1,075
Interest Recognized |  |  |  |  |
Total impaired loans with no related allowance recorded | 12 | 15 | 39 | 54 | 15
Consumer |  |  |  |  |
Interest Recognized |  |  |  |  |
Total trouble debt restructuring | 1,227 |  | 1,227 |  | 1,263
Consumer | Class of Financing Receivable |  |  |  |  |
Recorded investment: |  |  |  |  |
Total impaired loans with no related allowance | 1,230 |  | 1,230 |  | 1,297
Unpaid principal balance: |  |  |  |  |
Total impaired loans with no related allowance recorded | 1,230 |  | 1,230 |  | 1,298
Average recorded investment: |  |  |  |  |
Total impaired loans with no related allowance recorded | 1,229 | 1,263 | 1,191 | 1,201 | 1,263
Interest Recognized |  |  |  |  |
Total impaired loans with no related allowance recorded |  | 1 | 1 | 2 | 1
Foreign |  |  |  |  |
Interest Recognized |  |  |  |  |
Total trouble debt restructuring | 366 |  | 366 |  | 386
Foreign | Class of Financing Receivable |  |  |  |  |
Recorded investment: |  |  |  |  |
Total impaired loans with no related allowance | 752 |  | 752 |  | 752
Unpaid principal balance: |  |  |  |  |
Total impaired loans with no related allowance recorded | 752 |  | 752 |  | 752
Average recorded investment: |  |  |  |  |
Total impaired loans with no related allowance recorded | 752 | 632 | 752 | 480 | 632
Interest Recognized |  |  |  |  |
Total impaired loans with no related allowance recorded | $ 4 | $ 4 | $ 12 | $ 13 | $ 4

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