| **Accumulated Other Comprehensive Income (Loss) - Reclassifications (Details) - USD ($) $ in Thousands**                                                        | 3 Months Ended | 9 Months Ended |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------|----------------|
||
| **Reclassification Adjustments out of Accumulated Other Comprehensive Income [Line Items]**                                                                     |           |           |   |   |
| Other income - net realized gains on sales of available for sale securities                                                                                     | $ 839          | $ 1,115        | $ 2,542 | $ 2,047 |
| Interest expense - subordinated debentures and term loans                                                                                                       | 1,797          | 1,666          | 5,368 | 4,996 |
| Income tax expense                                                                                                                                              | (7,469)        | (6,557)        | (19,759) | (21,247) |
| Total reclassifications for the period, net of tax                                                                                                              | 339            | 490            | 1,029 | 633 |
| Unrealized gains (losses) on available for sale securities                                                                                                      |           |           |   |   |
| **Reclassification Adjustments out of Accumulated Other Comprehensive Income [Line Items]**                                                                     |           |           |   |   |
| Total reclassifications for the period, net of tax                                                                                                              | 545            | 725            | 1,652 | 1,331 |
| Unrealized gains (losses) on cash flow hedges                                                                                                                   |           |           |   |   |
| **Reclassification Adjustments out of Accumulated Other Comprehensive Income [Line Items]**                                                                     |           |           |   |   |
| Total reclassifications for the period, net of tax                                                                                                              | (206)          | (235)          | (623) | (698) |
| 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                                                                                     | 839            | 1,115          | 2,542 | 2,047 |
| Income tax expense                                                                                                                                              | (294)          | (390)          | (890) | (716) |
| 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]**                                                                     |           |           |   |   |
| Income tax expense                                                                                                                                              | 111            | 127            | 336 | 376 |
| Amount Reclassified from Accumulated Other Comprehensive Income (Loss) for the Period | Unrealized gains (losses) on cash flow hedges | Interest rate contracts |           |           |   |   |
| **Reclassification Adjustments out of Accumulated Other Comprehensive Income [Line Items]**                                                                     |           |           |   |   |
| Interest expense - subordinated debentures and term loans                                                                                                       | $ (317)        | $ (362)        | $ (959) | $ (1,074) |

| 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=73527792&loc=d3e27357-111563
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|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - 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 740 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a),(b) -URI http://asc.fasb.org/extlink&oid=65882285&loc=d3e32639-109319Reference 2: 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 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=6515339
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| 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=63488584&loc=d3e20235-122688
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| - 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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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount after tax of reclassification adjustments of other comprehensive income (loss).
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14A -URI http://asc.fasb.org/extlink&oid=66004124&loc=SL7669686-108580Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 55 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=66004921&loc=d3e1436-108581
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