| **Income Tax - Narrative (Details) (USD $)In Thousands, unless otherwise specified** | 12 Months Ended |         |        |
|--------------------------------------------------------------------------------------|-----------------|---------|--------|
||
| **Valuation Allowance [Line Items]**                                                 |            |    |   |
| Increase (Decrease) in Deferred Tax Assets                                           | $ 29,663        |    |   |
| Valuation Allowance                                                                  | 17,171          | 13,859  | 15,701 |
| Additional paid-in capital                                                           | 393,783         | 256,843 |   |
| Unrecorded deferred tax liability                                                    | 4,688           |    |   |
| State and Local Jurisdiction                                                         |            |    |   |
| **Valuation Allowance [Line Items]**                                                 |            |    |   |
| State Tax Loss Carryforward                                                          | 136,769         |    |   |
| Pension and Other Employee Benefits                                                  |            |    |   |
| **Valuation Allowance [Line Items]**                                                 |            |    |   |
| Increase (Decrease) in Deferred Tax Assets                                           | (5,880)         |    |   |
| Deferred Compensation                                                                |            |    |   |
| **Valuation Allowance [Line Items]**                                                 |            |    |   |
| Increase (Decrease) in Deferred Tax Assets                                           | (1,702)         |    |   |
| Available-for-sale securities                                                        |            |    |   |
| **Valuation Allowance [Line Items]**                                                 |            |    |   |
| Increase (Decrease) in Deferred Tax Assets                                           | 8,030           |    |   |
| Merger with CFS Bancorp, Inc. (Citizens)                                             |            |    |   |
| **Valuation Allowance [Line Items]**                                                 |            |    |   |
| Increase (Decrease) in Deferred Tax Assets                                           | 30,265          |    |   |
| Additional paid-in capital                                                           | 13,393          |    |   |
| Deferred State Taxes                                                                 |            |    |   |
| **Valuation Allowance [Line Items]**                                                 |            |    |   |
| Valuation Allowance                                                                  | $ 17,171        |    |   |

| X                                                                                                                                                                                                                                                                    |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Increase (Decrease) in Deferred Tax Assets
+ References
No definition available.
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|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Excess of issue price over par or stated value of the entity's capital stock and amounts received from other transactions involving the entity's stock or stockholders. Includes adjustments to additional paid in capital. Some examples of such adjustments include recording the issuance of debt with a beneficial conversion feature and certain tax consequences of equity instruments awarded to employees. Use this element for the aggregate amount of additional paid-in capital associated with common and preferred stock. For additional paid-in capital associated with only common stock, use the element additional paid in capital, common stock. For additional paid-in capital associated with only preferred stock, use the element additional paid in capital, preferred stock.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 31 -Article 5Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.30(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of deferred tax liability not recognized because of the exceptions to comprehensive recognition of deferred taxes related to undistributed earnings of domestic subsidiaries.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.
+ References
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| X                                                                                                                                                               |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------|
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