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Loans and Allowance for Loan Losses - Additional Information (Detail) (USD $) | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2013 | Sep. 30, 2012 | Sep. 30, 2013 | Sep. 30, 2012 | Dec. 31, 2012
Receivables [Abstract] |  |  |  |  |
Total loans | $ 1,075,487,000 | $ 1,035,288,000 | $ 1,075,487,000 | $ 1,035,288,000 | $ 1,041,189,000
Amount of increase in total loans |  |  | 34,300,000 |  |
Percentage increase in total loans |  |  | 3.30% |  |
Interest income recognized on impaired loans | $ 700,000 | $ 400,000 | $ 2,200,000 | $ 1,100,000 |
Number of past due days for loans modified as TDR | 30 days | 30 days | 30 days | 30 days |

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- Definition Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=28368275&loc=d3e5074-111524 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=28367877&loc=d3e4428-111522 + Details
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