| **Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands** | 3 Months Ended | 6 Months Ended |
|-------------------------------------------------------------------------------|----------------|----------------|
||
| **Accumulated Other Comprehensive Income (Loss) [Roll Forward]**              |           |           |   |  |   |
| Beginning balance                                                             |           |           | $ (7,475) | [1] | $ (17,605) |
| Other comprehensive income before reclassifications                           |           |           | (2,578) |  | 8,142 |
| Amounts reclassified from accumulated other comprehensive income              |           |           | 4 |  | (445) |
| Other comprehensive income (loss), net of tax                                 | $ (3,913)      | $ 4,405        | (2,574) |  | 7,697 |
| Ending balance                                                                | (10,049)       | (9,908)        | (10,049) |  | (9,908) |
| Unrealized gains (losses) on available for sale securities [Member]           |           |           |   |  |   |
| **Accumulated Other Comprehensive Income (Loss) [Roll Forward]**              |           |           |   |  |   |
| Beginning balance                                                             |           |           | (3,017) |  | (14,476) |
| Other comprehensive income before reclassifications                           |           |           | (2,515) |  | 8,372 |
| Amounts reclassified from accumulated other comprehensive income              |           |           | 0 |  | (445) |
| Other comprehensive income (loss), net of tax                                 |           |           | (2,515) |  | 7,927 |
| Ending balance                                                                | (5,532)        | (6,549)        | (5,532) |  | (6,549) |
| Interest rate swaps                                                           |           |           |   |  |   |
| **Accumulated Other Comprehensive Income (Loss) [Roll Forward]**              |           |           |   |  |   |
| Beginning balance                                                             |           |           | (324) |  | 0 |
| Other comprehensive income before reclassifications                           |           |           | (63) |  | (230) |
| Amounts reclassified from accumulated other comprehensive income              |           |           | 4 |  | 0 |
| Other comprehensive income (loss), net of tax                                 |           |           | (59) |  | (230) |
| Ending balance                                                                | (383)          | (230)          | (383) |  | (230) |
| Defined benefit plan items [Member]                                           |           |           |   |  |   |
| **Accumulated Other Comprehensive Income (Loss) [Roll Forward]**              |           |           |   |  |   |
| Beginning balance                                                             |           |           | (4,134) |  | (3,129) |
| Other comprehensive income before reclassifications                           |           |           | 0 |  | 0 |
| Amounts reclassified from accumulated other comprehensive income              |           |           | 0 |  | 0 |
| Other comprehensive income (loss), net of tax                                 |           |           | 0 |  | 0 |
| Ending balance                                                                | $ (4,134)      | $ (3,129)      | $ (4,134) |  | $ (3,129) |
|                                                                               |
| [1]Derived from audited consolidated financial statements                     |

| X                                                                                                                                                                                                                                                                                              |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
+ References
No definition available.
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|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.
+ References
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|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount after tax, before reclassification adjustments of other comprehensive income (loss).
+ References
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|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount after tax of other comprehensive income (loss) attributable to parent entity.
+ References
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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount after tax of reclassification adjustments of other comprehensive income (loss).
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