| **Accounting for Certain Loans Acquired in a Purchase  - Accretable Yield or Income Expected to be Collected (Details) (USD $)In Thousands, unless otherwise specified** | 3 Months Ended |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------|
||
| **Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]**                                           |           |   |
| Beginning balance                                                                                                                                                        | $ 19,299       |   |
| Accretion                                                                                                                                                                | (1,769)        |   |
| Reclassification from nonaccretable                                                                                                                                      | 491            |   |
| Disposals                                                                                                                                                                | (195)          |   |
| Ending balance                                                                                                                                                           | 17,826         |   |
| Merger with CFS Bancorp, Inc. (Citizens)                                                                                                                                 |           |   |
| **Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]**                                           |           |   |
| Beginning balance                                                                                                                                                        | 13,435         |   |
| Accretion                                                                                                                                                                | (1,155)        |   |
| Reclassification from nonaccretable                                                                                                                                      | 238            |   |
| Disposals                                                                                                                                                                | (107)          |   |
| Ending balance                                                                                                                                                           | 12,411         |   |
| SCB Bank                                                                                                                                                                 |           |   |
| **Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]**                                           |           |   |
| Beginning balance                                                                                                                                                        | 5,864          |   |
| Additions                                                                                                                                                                |           | 5,142 |
| Accretion                                                                                                                                                                | (614)          | (771) |
| Reclassification from nonaccretable                                                                                                                                      | 253            |   |
| Disposals                                                                                                                                                                | (88)           |   |
| Ending balance                                                                                                                                                           | $ 5,415        | $ 4,371 |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of the excess of a loan's cash flows expected to be collected over the investor's initial investment in acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 15 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=27045933&loc=d3e13503-111538Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=6379141&loc=d3e15032-111544
+ Details**Name:**us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYield**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of decrease from accretion of the excess of a loan's cash flows expected to be collected over the investor's initial investment in acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 15 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=27045933&loc=d3e13503-111538Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=6379141&loc=d3e15032-111544
+ Details**Name:**us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAccretion**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of additions to the excess of a loan's cash flows expected to be collected over the investor's initial investment in acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 15 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=27045933&loc=d3e13503-111538Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=6379141&loc=d3e15032-111544
+ Details**Name:**us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAdditions**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of reduction, resulting from a sale or transfer of a loan, in the excess of a loan's cash flows expected to be collected over the investor's initial investment in acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 15 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=27045933&loc=d3e13503-111538Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=6379141&loc=d3e15032-111544
+ Details**Name:**us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldDisposalsOfLoans**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**duration |
| X                                                                                                                                                                                                                                           |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldMovementScheduleRollForward**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of increase of reclassification from nonaccretable difference to the excess of a loan's cash flows expected to be collected over the investor's initial investment in acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 15 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=27045933&loc=d3e13503-111538Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=6379141&loc=d3e15032-111544
+ Details**Name:**us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldReclassificationsFromNonaccretableDifference**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |