| **Investment Securities - Securities Temporarily Impaired (Details) - USD ($) $ in Thousands** | Dec. 31, 2016 | Dec. 31, 2015 |
|------------------------------------------------------------------------------------------------|---------------|---------------|
| **Schedule of Available-for-sale Securities [Line Items]**                                     |          |          |
| Less than 12 months, Fair Value                                                                | $ 276,518     | $ 168,818     |
| Less than 12 months, Unrealized Losses                                                         | (7,383)       | (2,525)       |
| 12 months or more, Fair Value                                                                  | 3,033         | 21,048        |
| 12 months or more, Unrealized Losses                                                           | (191)         | (950)         |
| Fair Value                                                                                     | 279,551       | 189,866       |
| Unrealized Losses                                                                              | (7,574)       | (3,475)       |
| U.S. Government-sponsored agencies                                                             |          |          |
| **Schedule of Available-for-sale Securities [Line Items]**                                     |          |          |
| Less than 12 months, Fair Value                                                                | 6,642         | 45,311        |
| Less than 12 months, Unrealized Losses                                                         | (233)         | (1,469)       |
| 12 months or more, Fair Value                                                                  | 0             | 17,185        |
| 12 months or more, Unrealized Losses                                                           | 0             | (815)         |
| Fair Value                                                                                     | 6,642         | 62,496        |
| Unrealized Losses                                                                              | (233)         | (2,284)       |
| Mortgage-backed securities                                                                     |          |          |
| **Schedule of Available-for-sale Securities [Line Items]**                                     |          |          |
| Less than 12 months, Fair Value                                                                | 197,528       | 120,915       |
| Less than 12 months, Unrealized Losses                                                         | (3,090)       | (1,027)       |
| 12 months or more, Fair Value                                                                  | 2,905         | 910           |
| 12 months or more, Unrealized Losses                                                           | (184)         | (71)          |
| Fair Value                                                                                     | 200,433       | 121,825       |
| Unrealized Losses                                                                              | (3,274)       | (1,098)       |
| State and political subdivisions                                                               |          |          |
| **Schedule of Available-for-sale Securities [Line Items]**                                     |          |          |
| Less than 12 months, Fair Value                                                                | 72,348        | 2,528         |
| Less than 12 months, Unrealized Losses                                                         | (4,060)       | (24)          |
| 12 months or more, Fair Value                                                                  | 0             | 2,901         |
| 12 months or more, Unrealized Losses                                                           | 0             | (63)          |
| Fair Value                                                                                     | 72,348        | 5,429         |
| Unrealized Losses                                                                              | (4,060)       | (87)          |
| Other equity securities                                                                        |          |          |
| **Schedule of Available-for-sale Securities [Line Items]**                                     |          |          |
| Less than 12 months, Fair Value                                                                | 0             | 64            |
| Less than 12 months, Unrealized Losses                                                         | 0             | (5)           |
| 12 months or more, Fair Value                                                                  | 128           | 52            |
| 12 months or more, Unrealized Losses                                                           | (7)           | (1)           |
| Fair Value                                                                                     | 128           | 116           |
| Unrealized Losses                                                                              | $ (7)         | $ (6)         |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for twelve months or longer.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale in a continuous loss position.
+ References
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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
This item represents the aggregate fair value of investments in debt and equity securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities.
+ References
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|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for less than twelve months.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
This item represents the aggregate fair value of investments in debt and equity securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for less than twelve months.
+ References
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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
This item represents the aggregate fair value of investments in debt and equity securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for twelve months or longer.
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                     |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - 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.
+ References
No definition available.
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