| **Accumulated Other Comprehensive Income (Loss) - Reclassifications (Details) (USD $)In Thousands, unless otherwise specified**                    | 3 Months Ended | 6 Months Ended |
|----------------------------------------------------------------------------------------------------------------------------------------------------|----------------|----------------|
||
| **Reclassification Adjustments out of Accumulated Other Comprehensive Income [Line Items]**                                                        |           |           |   |   |
| Other income - net realized gains on sales of available for sale securities                                                                        | $ 844          | $ 239          | $ 1,425 | $ 487 |
| Interest expense - subordinated debentures and term loans                                                                                          | (1,648)        | (733)          | (3,289) | (1,458) |
| Other expenses - salaries and employee benefits                                                                                                    | (23,430)       | (20,536)       | (48,731) | (41,327) |
| Income tax expense                                                                                                                                 | (5,642)        | (4,155)        | (10,011) | (8,823) |
| NET INCOME                                                                                                                                         | 15,160         | 10,815         | 28,780 | 22,680 |
| Amount Reclassified from Accumulated Other Comprehensive Income (Loss) for the Period                                                              |           |           |   |   |
| **Reclassification Adjustments out of Accumulated Other Comprehensive Income [Line Items]**                                                        |           |           |   |   |
| NET INCOME                                                                                                                                         | 321            | (43)           | 474 | (643) |
| Amount Reclassified from Accumulated Other Comprehensive Income (Loss) for the Period | 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                                                                        | 844            | 239            | 1,425 | 487 |
| Income tax expense                                                                                                                                 | (295)          | (84)           | (499) | (170) |
| NET INCOME                                                                                                                                         | 549            | 155            | 926 | 317 |
| Amount Reclassified from Accumulated Other Comprehensive Income (Loss) for the Period | Unrealized gains (losses) on cash flow hedges              |           |           |   |   |
| **Reclassification Adjustments out of Accumulated Other Comprehensive Income [Line Items]**                                                        |           |           |   |   |
| Interest expense - subordinated debentures and term loans                                                                                          | (351)          | (192)          | (695) | (380) |
| Income tax expense                                                                                                                                 | 123            | 67             | 243 | 133 |
| NET INCOME                                                                                                                                         | (228)          | (125)          | (452) | (247) |
| Amount Reclassified from Accumulated Other Comprehensive Income (Loss) for the Period | Unrealized gains (losses) on defined benefit plans         |           |           |   |   |
| **Reclassification Adjustments out of Accumulated Other Comprehensive Income [Line Items]**                                                        |           |           |   |   |
| Other expenses - salaries and employee benefits                                                                                                    |      | (112)          |    | (1,097) |
| Income tax expense                                                                                                                                 |      | 39             |    | 384 |
| NET INCOME                                                                                                                                         | $ 0            | $ (73)         | $ 0 | $ (713) |

| 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
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27357-111563
+ Details**Name:**us-gaap_AvailableForSaleSecuritiesGrossRealizedGainLossNet**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(h)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph h -Article 4Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Income Tax Expense (or Benefit) -URI http://asc.fasb.org/extlink&oid=6515339Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a),(b) -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32639-109319
+ Details**Name:**us-gaap_IncomeTaxExpenseBenefit**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of the cost of borrowed funds accounted for as interest expense for debt.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.8) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 8 -Article 5
+ Details**Name:**us-gaap_InterestExpenseDebt**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - 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.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.4) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688
+ Details**Name:**us-gaap_LaborAndRelatedExpense**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Other Comprehensive Income -URI http://asc.fasb.org/extlink&oid=6519514Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Net Income -URI http://asc.fasb.org/extlink&oid=6518256Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04.19) -URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.18) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04.22) -URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913Reference 8: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 19 -Article 5Reference 9: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 20 -Article 9
+ Details**Name:**us-gaap_NetIncomeLoss**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**duration |
| X                                                                                                                                                                                                               |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |