| **Accumulated Other Comprehensive Income (Tables)**                                       | 3 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
|-------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
||
| **Equity [Abstract]**                                                                     |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
| Changes in Accumulated Other Comprehensive Income (Loss) [Table Text Block]               | The following tables present the changes in our accumulated other comprehensive income (loss), net of tax, by component for the periods indicated:(Dollars in thousands) Unrealized Gains (Losses) on Available-For-Sale Securities Interest Rate Swaps Defined Benefit Plan Items Total         Beginning balance January 1, 2014 $(14,476) $— $(3,129) $(17,605)Other comprehensive income before reclassifications 3,267 25 — 3,292Amounts reclassified from accumulated other comprehensive income — — — —Net current period other comprehensive income 3,267 25 — 3,292Ending balance March 31, 2014 $(11,209) $25 $(3,129) $(14,313)(Dollars in thousands) Unrealized Gains (Losses) on Available-For-Sale Securities Defined Benefit Plan Items Total       Beginning balance January 1, 2013 $3,650 $(3,973) $(323)Other comprehensive loss before reclassifications (2,985) — (2,985)Amounts reclassified from accumulated other comprehensive income (1,438) (154) (1,592)Net current period other comprehensive loss (4,423) (154) (4,577)Ending balance March 31, 2013 $(773) $(4,127) $(4,900) |
| Reclassifications out of Accumulated Other Comprehensive Income (Loss) [Table Text Block] | The following table presents the reclassifications out of our accumulated other comprehensive income (loss) for the three months ended March 31, 2014 and 2013:(Dollars in thousands)Amount Reclassified from AOCI   Three Months Ended March 31, 2014 Three Months Ended March 31, 2013 Line Item in the Consolidated Statement of OperationsAvailable-for-sale securities:     Net realized gains on sale of securities$— $(2,377) Securities gains, netIncome tax (benefit) expense— 939 Income tax expenseTotal, net of tax— (1,438)        Defined benefit plan items:        Net actuarial gains— (254) Personnel expenseIncome tax (benefit) expense— 100 Income tax expenseTotal, net of tax— (154)  Total reclassifications for the period$— $(1,592)                                                                                                                                                                                                                                                                                                                                                                                                                                         |

| X                                                                                                                                                  |
|----------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_EquityAbstract**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                  |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Tabular disclosure of information about items reclassified out of accumulated other comprehensive income (loss).
+ References
No definition available.
+ Details**Name:**us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTableTextBlock**Namespace Prefix:**us-gaap_**Data Type:**nonnum:textBlockItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Tabular disclosure of the components of accumulated 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=28358780&loc=SL7669686-108580
+ Details**Name:**us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock**Namespace Prefix:**us-gaap_**Data Type:**nonnum:textBlockItemType**Balance Type:**na**Period Type:**duration |