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Loans and Allowance for Loan Losses - Impaired Loans (Detail) (USD $) | 12 Months Ended
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Dec. 31, 2013 | Dec. 31, 2012
Impaired Loans By Type [Line Items] |  |
Unpaid Contractual Principal Balance, with no related allowance | $ 6,689,000 | $ 20,038,000
Impaired loans, Unpaid Contractual Principal Balance | 41,056,000 | 69,166,000
Recorded Principal Balance, with no related allowance | 3,500,000 | 11,752,000
Impaired loans, Recorded Principal Balance | 36,868,000 | 57,279,000
Impaired loans, Related Allowance |  |
Year-To-Date Average Recorded Principal Balance, with no related allowance | 8,917,000 | 16,770,000
Unpaid Contractual Principal Balance, with related allowance | 34,367,000 | 49,128,000
Recorded Principal Balance, with related allowance | 33,368,000 | 45,527,000
Impaired loans, Related Allowance | 12,386,000 | 17,189,000
Year-To-Date Average Recorded Principal Balance, with related allowance | 41,044,000 | 44,548,000
Impaired loans, Year-To-Date Average Recorded Principal Balance | 49,961,000 | 61,318,000
Commercial and Industrial [Member] |  |
Impaired Loans By Type [Line Items] |  |
Unpaid Contractual Principal Balance, with no related allowance | 2,229,000 | 1,926,000
Recorded Principal Balance, with no related allowance | 511,000 | 1,617,000
Impaired loans, Related Allowance |  |
Year-To-Date Average Recorded Principal Balance, with no related allowance | 1,205,000 | 3,140,000
Unpaid Contractual Principal Balance, with related allowance | 1,517,000 | 3,221,000
Recorded Principal Balance, with related allowance | 1,440,000 | 1,926,000
Impaired loans, Related Allowance | 792,000 | 924,000
Year-To-Date Average Recorded Principal Balance, with related allowance | 1,880,000 | 3,110,000
Commercial Vacant Land, Land Development, and Residential Construction [Member] |  |
Impaired Loans By Type [Line Items] |  |
Unpaid Contractual Principal Balance, with no related allowance | 475,000 | 2,356,000
Recorded Principal Balance, with no related allowance | 362,000 | 1,401,000
Impaired loans, Related Allowance |  |
Year-To-Date Average Recorded Principal Balance, with no related allowance | 991,000 | 1,848,000
Unpaid Contractual Principal Balance, with related allowance | 4,436,000 | 2,333,000
Recorded Principal Balance, with related allowance | 4,139,000 | 2,219,000
Impaired loans, Related Allowance | 844,000 | 1,367,000
Year-To-Date Average Recorded Principal Balance, with related allowance | 3,354,000 | 3,267,000
Commercial Real Estate - Owner Occupied [Member] |  |
Impaired Loans By Type [Line Items] |  |
Unpaid Contractual Principal Balance, with no related allowance | 1,270,000 | 2,368,000
Recorded Principal Balance, with no related allowance | 785,000 | 1,557,000
Impaired loans, Related Allowance |  |
Year-To-Date Average Recorded Principal Balance, with no related allowance | 1,084,000 | 3,139,000
Unpaid Contractual Principal Balance, with related allowance | 1,513,000 | 4,307,000
Recorded Principal Balance, with related allowance | 1,513,000 | 3,626,000
Impaired loans, Related Allowance | 528,000 | 1,388,000
Year-To-Date Average Recorded Principal Balance, with related allowance | 2,550,000 | 4,913,000
Commercial Real Estate - Non-Owner Occupied [Member] |  |
Impaired Loans By Type [Line Items] |  |
Unpaid Contractual Principal Balance, with no related allowance | 895,000 | 9,984,000
Recorded Principal Balance, with no related allowance | 733,000 | 5,492,000
Impaired loans, Related Allowance |  |
Year-To-Date Average Recorded Principal Balance, with no related allowance | 4,049,000 | 6,578,000
Unpaid Contractual Principal Balance, with related allowance | 21,088,000 | 33,818,000
Recorded Principal Balance, with related allowance | 21,072,000 | 32,964,000
Impaired loans, Related Allowance | 7,969,000 | 11,773,000
Year-To-Date Average Recorded Principal Balance, with related allowance | 28,388,000 | 25,061,000
Commercial Real Estate - Multi-Family and Residential Rental [Member] |  |
Impaired Loans By Type [Line Items] |  |
Unpaid Contractual Principal Balance, with no related allowance | 41,000 | 1,188,000
Recorded Principal Balance, with no related allowance | 1,000 | 413,000
Impaired loans, Related Allowance |  |
Year-To-Date Average Recorded Principal Balance, with no related allowance | 390,000 | 756,000
Unpaid Contractual Principal Balance, with related allowance | 3,219,000 | 4,471,000
Recorded Principal Balance, with related allowance | 2,684,000 | 3,923,000
Impaired loans, Related Allowance | 1,127,000 | 1,408,000
Year-To-Date Average Recorded Principal Balance, with related allowance | 2,915,000 | 7,429,000
Commercial Loans [Member] |  |
Impaired Loans By Type [Line Items] |  |
Unpaid Contractual Principal Balance, with no related allowance | 4,910,000 | 17,822,000
Impaired loans, Unpaid Contractual Principal Balance | 36,683,000 | 65,972,000
Recorded Principal Balance, with no related allowance | 2,392,000 | 10,480,000
Impaired loans, Recorded Principal Balance | 33,240,000 | 55,138,000
Impaired loans, Related Allowance |  |
Year-To-Date Average Recorded Principal Balance, with no related allowance | 7,719,000 | 15,461,000
Unpaid Contractual Principal Balance, with related allowance | 31,773,000 | 48,150,000
Recorded Principal Balance, with related allowance | 30,848,000 | 44,658,000
Impaired loans, Related Allowance | 11,260,000 | 16,860,000
Year-To-Date Average Recorded Principal Balance, with related allowance | 39,087,000 | 43,780,000
Impaired loans, Year-To-Date Average Recorded Principal Balance | 46,806,000 | 59,241,000
Retail Home Equity and Other [Member] |  |
Impaired Loans By Type [Line Items] |  |
Unpaid Contractual Principal Balance, with no related allowance | 507,000 | 580,000
Recorded Principal Balance, with no related allowance | 461,000 | 483,000
Impaired loans, Related Allowance |  |
Year-To-Date Average Recorded Principal Balance, with no related allowance | 471,000 | 579,000
Unpaid Contractual Principal Balance, with related allowance | 320,000 | 423,000
Recorded Principal Balance, with related allowance | 289,000 | 394,000
Impaired loans, Related Allowance | 96,000 | 204,000
Year-To-Date Average Recorded Principal Balance, with related allowance | 329,000 | 286,000
Retail 1-4 Family Mortgages [Member] |  |
Impaired Loans By Type [Line Items] |  |
Unpaid Contractual Principal Balance, with no related allowance | 1,272,000 | 1,636,000
Recorded Principal Balance, with no related allowance | 647,000 | 789,000
Impaired loans, Related Allowance |  |
Year-To-Date Average Recorded Principal Balance, with no related allowance | 727,000 | 730,000
Unpaid Contractual Principal Balance, with related allowance | 2,274,000 | 555,000
Recorded Principal Balance, with related allowance | 2,231,000 | 475,000
Impaired loans, Related Allowance | 1,030,000 | 125,000
Year-To-Date Average Recorded Principal Balance, with related allowance | 1,628,000 | 482,000
Retail Loans [Member] |  |
Impaired Loans By Type [Line Items] |  |
Unpaid Contractual Principal Balance, with no related allowance | 1,779,000 | 2,216,000
Impaired loans, Unpaid Contractual Principal Balance | 4,373,000 | 3,194,000
Recorded Principal Balance, with no related allowance | 1,108,000 | 1,272,000
Impaired loans, Recorded Principal Balance | 3,628,000 | 2,141,000
Impaired loans, Related Allowance |  |
Year-To-Date Average Recorded Principal Balance, with no related allowance | 1,198,000 | 1,309,000
Unpaid Contractual Principal Balance, with related allowance | 2,594,000 | 978,000
Recorded Principal Balance, with related allowance | 2,520,000 | 869,000
Impaired loans, Related Allowance | 1,126,000 | 329,000
Year-To-Date Average Recorded Principal Balance, with related allowance | 1,957,000 | 768,000
Impaired loans, Year-To-Date Average Recorded Principal Balance | $ 3,155,000 | $ 2,077,000

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