| **Accumulated Other Comprehensive Income - Reclassifications (Details) (USD $)In Thousands, unless otherwise specified**                                                                                                                                                                                                                                                                                                   | 3 Months Ended | 6 Months Ended |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------|----------------|
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| **Reclassification Adjustments out of Accumulated Other Comprehensive Income [Line Items]**                                                                                                                                                                                                                                                                                                                                |           |                |   |  |   |  |   |  |
| Other income - net realized gains on sales of available for sale securities                                                                                                                                                                                                                                                                                                                                                | $ 239          |                | $ 502 |  | $ 487 |  | $ 1,291 |  |
| Interest expense - subordinated debentures and term loans                                                                                                                                                                                                                                                                                                                                                                  | (733)          |                | (1,331) |  | (1,458) |  | (3,273) |  |
| Other expenses - salaries and employee benefits                                                                                                                                                                                                                                                                                                                                                                            | (20,536)       |                | (19,641) |  | (41,327) |  | (38,995) |  |
| Income tax expense (benefit)                                                                                                                                                                                                                                                                                                                                                                                               | (4,155)        |                | (3,288) |  | (8,823) |  | (8,788) |  |
| NET INCOME                                                                                                                                                                                                                                                                                                                                                                                                                 | 10,815         |                | 9,205 |  | 22,680 |  | 23,576 |  |
| Amount Reclassified from Accumulated Other Comprehensive Income for the Period                                                                                                                                                                                                                                                                                                                                             |           |                |   |  |   |  |   |  |
| **Reclassification Adjustments out of Accumulated Other Comprehensive Income [Line Items]**                                                                                                                                                                                                                                                                                                                                |           |                |   |  |   |  |   |  |
| NET INCOME                                                                                                                                                                                                                                                                                                                                                                                                                 | (43)           |                | 117 |  | (643) |  | 110 |  |
| Amount Reclassified from Accumulated Other Comprehensive Income for the Period | Unrealized gains (losses) on available for sale securities                                                                                                                                                                                                                                                                                |           |                |   |  |   |  |   |  |
| **Reclassification Adjustments out of Accumulated Other Comprehensive Income [Line Items]**                                                                                                                                                                                                                                                                                                                                |           |                |   |  |   |  |   |  |
| Other income - net realized gains on sales of available for sale securities                                                                                                                                                                                                                                                                                                                                                | 239            | [1]            | 502 | [1] | 487 | [1] | 1,291 | [1] |
| Income tax expense (benefit)                                                                                                                                                                                                                                                                                                                                                                                               | (84)           | [1]            | (176) | [1] | (170) | [1] | (452) | [1] |
| NET INCOME                                                                                                                                                                                                                                                                                                                                                                                                                 | 155            | [1]            | 326 | [1] | 317 | [1] | 839 | [1] |
| Amount Reclassified from Accumulated Other Comprehensive Income for the Period | Unrealized gains (losses) on cash flow hedges                                                                                                                                                                                                                                                                                             |           |                |   |  |   |  |   |  |
| **Reclassification Adjustments out of Accumulated Other Comprehensive Income [Line Items]**                                                                                                                                                                                                                                                                                                                                |           |                |   |  |   |  |   |  |
| Interest expense - subordinated debentures and term loans                                                                                                                                                                                                                                                                                                                                                                  | (192)          | [2]            |    | [2] | (380) | [2] |    | [2] |
| Income tax expense (benefit)                                                                                                                                                                                                                                                                                                                                                                                               | 67             | [2]            |    | [2] | 133 | [2] |    | [2] |
| NET INCOME                                                                                                                                                                                                                                                                                                                                                                                                                 | (125)          | [2]            |    | [2] | (247) | [2] |    | [2] |
| Amount Reclassified from Accumulated Other Comprehensive Income for the Period | Unrealized gains (losses) on defined benefit plans                                                                                                                                                                                                                                                                                        |           |                |   |  |   |  |   |  |
| **Reclassification Adjustments out of Accumulated Other Comprehensive Income [Line Items]**                                                                                                                                                                                                                                                                                                                                |           |                |   |  |   |  |   |  |
| Other expenses - salaries and employee benefits                                                                                                                                                                                                                                                                                                                                                                            | (112)          |                | (322) |  | (1,097) |  | (1,123) |  |
| Income tax expense (benefit)                                                                                                                                                                                                                                                                                                                                                                                               | 39             |                | 113 |  | 384 |  | 394 |  |
| NET INCOME                                                                                                                                                                                                                                                                                                                                                                                                                 | $ (73)         |                | $ (209) |  | $ (713) |  | $ (729) |  |
|                                                                                                                                                                                                                                                                                                                                                                                                                            |
| [1]For additional detail related to unrealized gains (losses) on available for sale securities and related amounts reclassified from accumulated other comprehensive income see NOTE 3. INVESTMENT SECURITIES.[2]For additional detail related to unrealized gains (losses) on cash flow hedges and related amounts reclassified from accumulated other comprehensive income see NOTE 6. DERIVATIVE FINANCIAL INSTRUMENTS. |

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| - Definition
This item represents the difference between the gross realized gains and losses realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. Additionally, this item would include any losses recognized for other than temporary impairments (OTTI) of the subject investments in debt and equity securities.
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| - Definition
The sum of the current income tax expense or benefit and the deferred income tax expense or benefit pertaining to continuing operations.
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| - Definition
Represents the portion of interest incurred in the period on debt arrangements that was charged against earnings.
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| - Definition
The aggregate amount of expenditures for salaries, wages, profit sharing and incentive compensation, and other employee benefits, including equity-based compensation, and pension and other postretirement benefit expense.
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| - Definition
The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.
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