| **Accounting for Certain Loans Acquired in a Purchase (Details) (USD $)In Thousands, unless otherwise specified**              | 3 Months Ended | 8 Months Ended | 9 Months Ended |          |
|--------------------------------------------------------------------------------------------------------------------------------|----------------|----------------|----------------|----------|
||
| **Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]**                |           |           |           |     |   |
| Carrying amount of loans acquired                                                                                              | $ 52,851       |           |           | $ 52,851 | $ 65,600 |
| **Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]** |           |           |           |     |   |
| Beginning balance                                                                                                              | 3,959          | 9,048          | 9,774          | 5,142    |   |
| Accretions                                                                                                                     | (413)          | (2,612)        | (3,338)        | (1,596)  |   |
| Ending balance                                                                                                                 | 3,546          | 6,436          | 6,436          | 3,546    |   |
| Commercial and industrial loans                                                                                                |           |           |           |     |   |
| **Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]**                |           |           |           |     |   |
| Carrying amount of loans acquired                                                                                              | 6,265          |           |           | 6,265    | 8,542 |
| Agriculture production financing and other loans to farmers                                                                    |           |           |           |     |   |
| **Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]**                |           |           |           |     |   |
| Carrying amount of loans acquired                                                                                              | 1,382          |           |           | 1,382    | 1,127 |
| Real estate loans - Construction                                                                                               |           |           |           |     |   |
| **Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]**                |           |           |           |     |   |
| Carrying amount of loans acquired                                                                                              | 8              |           |           | 8        | 58 |
| Real estate loans - Commercial and farm land                                                                                   |           |           |           |     |   |
| **Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]**                |           |           |           |     |   |
| Carrying amount of loans acquired                                                                                              | 18,553         |           |           | 18,553   | 24,259 |
| Real estate loans - Residential                                                                                                |           |           |           |     |   |
| **Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]**                |           |           |           |     |   |
| Carrying amount of loans acquired                                                                                              | 9,614          |           |           | 9,614    | 12,118 |
| Real estate loans - Home equity                                                                                                |           |           |           |     |   |
| **Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]**                |           |           |           |     |   |
| Carrying amount of loans acquired                                                                                              | 16,529         |           |           | 16,529   | 18,805 |
| Individuals' loans for household and other personal expenditures                                                               |           |           |           |     |   |
| **Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]**                |           |           |           |     |   |
| Carrying amount of loans acquired                                                                                              | 336            |           |           | 336      | 691 |
| Other Loans                                                                                                                    |           |           |           |     |   |
| **Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]**                |           |           |           |     |   |
| Carrying amount of loans acquired                                                                                              | $ 164          |           |           | $ 164    |    |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of the excess of a loan's cash flows expected to be collected over the investor's initial investment in acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 15 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=27045933&loc=d3e13503-111538Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=6379141&loc=d3e15032-111544
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of decrease from accretion of the excess of a loan's cash flows expected to be collected over the investor's initial investment in acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 15 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=27045933&loc=d3e13503-111538Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=6379141&loc=d3e15032-111544
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| X                                                                                                                                                                                                                                           |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                                                                                              |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The recorded balance, net of any applicable reductions (for example, unamortized accretable yield and allowance for loan losses).  This relates to loans not accounted for debt securities with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 15 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=27045933&loc=d3e13503-111538Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=6379141&loc=d3e15032-111544
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