| **Accumulated Other Comprehensive Income (Loss) - Reclassifications (Loss) (Details) - USD ($) $ in Thousands**                     | 3 Months Ended | 12 Months Ended |
|-------------------------------------------------------------------------------------------------------------------------------------|----------------|-----------------|
||
| **Reclassification Adjustments out of Accumulated Other Comprehensive Income [Line Items]**                                         |           |            |   |   |   |   |   |   |   |   |   |
| Interest expense - subordinated debentures and term loans                                                                           |           |            |   |   |   |   |   |   | $ (6,661) | $ (6,616) | $ (3,531) |
| Other expenses - salaries and employee benefits                                                                                     |           |            |   |   |   |   |   |   | (101,908) | (96,499) | (85,413) |
| Income tax expense                                                                                                                  | $ (4,418)      | $ (6,557)       | $ (8,856) | $ (5,834) | $ (5,638) | $ (5,980) | $ (5,888) | $ (4,617) | (25,665) | (22,123) | (15,884) |
| NET INCOME                                                                                                                          | $ 14,177       | $ 17,067        | $ 17,968 | $ 16,172 | $ 15,260 | $ 16,122 | $ 15,160 | $ 13,620 | 65,384 | 60,162 | 44,530 |
| Amount Reclassified from Accumulated Other Comprehensive Income (Loss)                                                              |           |            |   |   |   |   |   |   |   |   |   |
| **Reclassification Adjustments out of Accumulated Other Comprehensive Income [Line Items]**                                         |           |            |   |   |   |   |   |   |   |   |   |
| NET INCOME                                                                                                                          |           |            |   |   |   |   |   |   | 1,006 | 1,748 | (1,438) |
| Amount Reclassified from Accumulated Other Comprehensive Income (Loss) | 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                                                         |           |            |   |   |   |   |   |   | 2,670 | 3,581 | 487 |
| Income tax expense                                                                                                                  |           |            |   |   |   |   |   |   | (934) | (1,253) | (170) |
| NET INCOME                                                                                                                          |           |            |   |   |   |   |   |   | 1,736 | 2,328 | 317 |
| Amount Reclassified from Accumulated Other Comprehensive Income (Loss) | Unrealized gains (losses) on cash flow hedges              |           |            |   |   |   |   |   |   |   |   |   |
| **Reclassification Adjustments out of Accumulated Other Comprehensive Income [Line Items]**                                         |           |            |   |   |   |   |   |   |   |   |   |
| Interest expense - subordinated debentures and term loans                                                                           |           |            |   |   |   |   |   |   | (1,427) | (1,411) | (935) |
| Income tax expense                                                                                                                  |           |            |   |   |   |   |   |   | 499 | 493 | 327 |
| NET INCOME                                                                                                                          |           |            |   |   |   |   |   |   | (928) | (918) | (608) |
| Amount Reclassified from Accumulated Other Comprehensive Income (Loss) | Unrealized gains (losses) on defined benefit plans         |           |            |   |   |   |   |   |   |   |   |   |
| **Reclassification Adjustments out of Accumulated Other Comprehensive Income [Line Items]**                                         |           |            |   |   |   |   |   |   |   |   |   |
| Other expenses - salaries and employee benefits                                                                                     |           |            |   |   |   |   |   |   | 305 | 520 | (1,765) |
| Income tax expense                                                                                                                  |           |            |   |   |   |   |   |   | (107) | (182) | 618 |
| NET INCOME                                                                                                                          |           |            |   |   |   |   |   |   | $ 198 | $ 338 | $ (1,147) |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - 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.
+ References
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|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.
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| - Definition
Amount of the cost of borrowed funds accounted for as interest expense for debt.
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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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| - Definition
Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.
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No definition available.
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