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Asset Purchases - Additional Information (Detail) (USD $) | 3 Months Ended | 12 Months Ended | 3 Months Ended | 1 Months Ended
--- | --- | --- | --- | ---
Mar. 31, 2014 | Mar. 31, 2013 | Dec. 31, 2013 | Dec. 31, 2014 Scenario, Forecast [Member] | Mar. 31, 2014 Knisely [Member] | Mar. 31, 2014 Hicksville [Member] | Dec. 31, 2013 Custar [Member]
Business Acquisition [Line Items] |  |  |  |  |  |  |
Recognition of core deposit intangible asset with acquired purchase |  |  |  |  | $ 1,100,000 | $ 1,090,000 | $ 1,170,000
Number of years amortized on straight line basis |  |  |  |  | 7 years |  |
Number of years amortized over an estimated remaining economic useful life of deposits |  |  |  |  |  | 7 years | 7 years
Amortization expense | $ 120,000 | $ 78,000 | $ 319,000 | $ 480,000 |  |  |

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