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Allowance for Loan Losses - Additional Information (Detail) (USD $) | 3 Months Ended | 9 Months Ended | 12 Months Ended
--- | --- | --- | ---
Sep. 30, 2013 Contract | Sep. 30, 2012 Contract | Sep. 30, 2013 Contract D | Sep. 30, 2012 Contract | Dec. 31, 2012
Receivables [Abstract] |  |  |  |  |
Troubled debt restructurings (TDRs) |  |  | $ 2,100,000 |  | $ 6,300,000
TDRs performing under the restructured terms | 834,000 |  | 834,000 |  | 1,600,000
New loans modified under TDRs | 0 | 0 | 0 | 0 |
Troubled debt restructuring loan subsequent default | $ 0 | $ 0 | $ 0 | $ 0 |
Troubled debt restructuring loan subsequent default period |  |  | 90 |  |

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- Definition Financing receivable modification as troubled debt restructuring that subsequently defaulted. + References No definition available. + Details
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- Definition Performing troubled debt restructurings. + References No definition available. + Details
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- Definition Number of financing receivables that have been modified by troubled debt restructurings. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 33 -URI http://asc.fasb.org/extlink&oid=28368275&loc=SL6953676-111524 + Details
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- Definition Pre-modification amount of investment in financing receivables modified by troubled debt restructurings. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 33 -URI http://asc.fasb.org/extlink&oid=28368275&loc=SL6953676-111524 + Details
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- Definition Amount of investment related to financing receivables modified by troubled debt restructurings within the previous 12 months, for which there was a payment default. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 34 -URI http://asc.fasb.org/extlink&oid=28368275&loc=SL6953682-111524 + Details
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- Details
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