| **Investment Securities Amortized Cost and Estimated Fair Value of Held to Maturity Securities (Details) (USD $)In Thousands, unless otherwise specified** | Jun. 30, 2013 | Dec. 31, 2012 | Jun. 30, 2012 |
|------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------|---------------|---------------|
| **Schedule of Held-to-maturity Securities [Line Items]**                                                                                                   |          |          |          |
| Amortized Cost                                                                                                                                             | $ 177,264     | $ 143,320     | $ 135,775     |
| Unrealized Gains                                                                                                                                           | 4,161         | 7,128         | 7,894         |
| Unrealized Losses                                                                                                                                          | (6,635)       | (201)         | (41)          |
| Fair Value (Estimated)                                                                                                                                     | 174,790       | 150,247       | 143,628       |
| US Treasury and Government [Member]                                                                                                                        |          |          |          |
| **Schedule of Held-to-maturity Securities [Line Items]**                                                                                                   |          |          |          |
| Amortized Cost                                                                                                                                             | 92,179        | 60,919        | 41,197        |
| Unrealized Gains                                                                                                                                           | 10            | 242           | 282           |
| Unrealized Losses                                                                                                                                          | (5,944)       | (182)         | (33)          |
| Fair Value (Estimated)                                                                                                                                     | 86,245        | 60,979        | 41,446        |
| Collateralized Mortgage Backed Securities [Member]                                                                                                         |          |          |          |
| **Schedule of Held-to-maturity Securities [Line Items]**                                                                                                   |          |          |          |
| Amortized Cost                                                                                                                                             | 42,389        | 39,193        | 49,992        |
| Unrealized Gains                                                                                                                                           | 1,883         | 2,850         | 3,524         |
| Unrealized Losses                                                                                                                                          | (625)         | (19)          | (8)           |
| Fair Value (Estimated)                                                                                                                                     | 43,647        | 42,024        | 53,508        |
| US States and Political Subdivisions Debt Securities [Member]                                                                                              |          |          |          |
| **Schedule of Held-to-maturity Securities [Line Items]**                                                                                                   |          |          |          |
| Amortized Cost                                                                                                                                             | 42,396        | 42,908        | 44,286        |
| Unrealized Gains                                                                                                                                           | 2,268         | 4,036         | 4,088         |
| Unrealized Losses                                                                                                                                          | (66)          | 0             | 0             |
| Fair Value (Estimated)                                                                                                                                     | 44,598        | 46,944        | 48,374        |
| Corporate Debt Securities [Member]                                                                                                                         |          |          |          |
| **Schedule of Held-to-maturity Securities [Line Items]**                                                                                                   |          |          |          |
| Amortized Cost                                                                                                                                             | 300           | 300           | 300           |
| Unrealized Gains                                                                                                                                           | 0             | 0             | 0             |
| Unrealized Losses                                                                                                                                          | 0             | 0             | 0             |
| Fair Value (Estimated)                                                                                                                                     | $ 300         | $ 300         | $ 300         |

| X                                                                                                                                                                                                                                                                                                                                                                                                                      |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of investments in debt securities categorized as held-to-maturity valued at amortized cost, excludes other than temporary impairment (OTTI).
+ References
No definition available.
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|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
This item represents the aggregate fair value of investments in debt securities as of the balance sheet date and which are categorized as held-to-maturity.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 19 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.  This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 137 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.  This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6872113&loc=d3e27232-111563
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
As of the balance sheet date, the excess of fair value over carrying value (amortized cost) of a debt security categorized as held-to-maturity, exclusive of dividend or interest income recognized but not yet received and exclusive of any write-downs for other-than-temporary impairment. Such item represents the gross unrecognized holding gain.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 19 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.  This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 137 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.  This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6872113&loc=d3e27232-111563
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|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
As of the balance sheet date, the excess of carrying value (amortized cost) over fair value of a debt security categorized as held-to-maturity, exclusive of dividend or interest income recognized but not yet received and exclusive of any write-downs for other-than-temporary impairment. Such item represents the gross unrecognized holding loss.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 19 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.  This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 137 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.  This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6872113&loc=d3e27232-111563
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| X                                                                                                                                                                               |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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