| **Purchase and Assumption - Assets and Liabilities of SCB Recorded at Provisional Fair Value (Detail) (USD $)In Thousands, unless otherwise specified** | 12 Months Ended | 0 Months Ended |     |
|---------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------|----------------|-----|
||
| **Business Acquisition [Line Items]**                                                                                                                   |            |           |     |   |   |   |   |   |   |   |
| Cash and due from banks (1)                                                                                                                             |            | $ 29,113       | [1] |   |   |   |   |   |   |   |
| Investment securities, available for sale                                                                                                               |            | 18,896         |     |   |   |   |   |   |   |   |
| Federal Home Loan Bank stock                                                                                                                            |            | 1,761          |     |   |   |   |   |   |   |   |
| Total Loans                                                                                                                                             |            | 93,793         |     |   |   |   |   | 51,042 | 11,181 | 31,570 |
| Premises                                                                                                                                                |            | 1,516          |     |   |   |   |   |   |   |   |
| Core deposit intangible                                                                                                                                 |            | 484            |     |   |   |   |   |   |   |   |
| Other assets                                                                                                                                            |            | 560            |     |   |   |   |   |   |   |   |
| Total Assets Purchased                                                                                                                                  |            | 146,123        |     |   |   |   |   |   |   |   |
| Total Deposits                                                                                                                                          |            | 125,909        |     | 13,715 | 14,746 | 25,843 | 71,605 |   |   |   |
| Federal Home Loan Bank advances                                                                                                                         |            | 10,286         |     |   |   |   |   |   |   |   |
| Other liabilities                                                                                                                                       |            | 804            |     |   |   |   |   |   |   |   |
| Total Liabilities Assumed                                                                                                                               |            | 136,999        |     |   |   |   |   |   |   |   |
| Net Gain on Acquisition                                                                                                                                 | $ 9,124         | $ 9,124        |     |   |   |   |   |   |   |   |
|                                                                                                                                                         |
| [1]Includes $17,200,000 cash received from the FDIC.                                                                                                    |

| X                                                                                                                                                                                                                                                                                                                           |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Business Acquisition, Purchase Price Allocation, Cash and Due from Banks
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No definition available.
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| X                                                                                                                                                                                                                                                                                                                                            |
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| - Definition
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No definition available.
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| X                                                                                                                                                                                                                                                                                                                                     |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Business Acquisition, Purchase Price Allocation, Federal Home Loan Bank stock
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No definition available.
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| X                                                                                                                                                                                                                                                                                                                                         |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Business Acquisition, Purchase Price Allocation, Liabilities Assumed, Deposits
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No definition available.
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| X                                                                                                                                                                                                                                                                                                                |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Business Acquisition, Purchase Price Allocation, Loans Receivable
+ References
No definition available.
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| X                                                                                                                                                                |
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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
In a business combination in which the amount of net identifiable assets acquired and liabilities assumed exceeds the aggregate consideration transferred or to be transferred (as defined), this element represents the amount of gain recognized by the entity.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of assets acquired at the acquisition date.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of facility held for productive use including, but not limited to, office, production, storage and distribution facilities, acquired at the acquisition date.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of investments in debt and equity securities, including, but not limited to, held-to-maturity, trading and available-for-sale expected to be converted to cash, sold or exchanged within one year or the normal operating cycle, if longer, acquired at the acquisition date.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The amount of identifiable intangible assets recognized as of the acquisition date.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of liabilities assumed at the acquisition date.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of other liabilities due after one year or the normal operating cycle, if longer, assumed at the acquisition date.
+ References
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|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of other assets expected to be realized or consumed after one year or the normal operating cycle, if longer, acquired at the acquisition date.
+ References
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