| **Supplemental Comprehensive Income Disclosures (Tables)**          | 9 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
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| **Supplemental Comprehensive Income Disclosures [Abstract]**        |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
| Schedule of Amounts Recognized in Other Comprehensive Income (Loss) | The following table identifies the related tax effects allocated to each component of other comprehensive income (“OCI”) in the Condensed Consolidated Statements of Comprehensive Income.  Reclassification adjustments related to securities available for sale are included in the "Net securities gains" line in the Condensed Consolidated Statements of Income.  The non-credit related gains on securities not expected to be sold are included in the "Noninterest Income" section of the Condensed Consolidated Statements of Income. For the Nine-Months Ended September 30 2013 2012 Pretax Amount Tax (Expense) Benefit Net of Tax Amount Pretax Amount Tax (Expense) Benefit Net of Tax Amount (dollars in thousands)Unrealized (losses) gains on securities:           Unrealized holding (losses) gains on securities arising during the period$(36,585) $12,799 $(23,786) $3,165 $(1,100) $2,065Non-credit related gains on securities not expected to be sold4,941 (1,729) 3,212 1,549 (542) 1,007Reclassification adjustment for gains on securities included in net income(237) 83 (154) (163) 57 (106)Total unrealized (losses) gains on securities(31,881) 11,153 (20,728) 4,551 (1,585) 2,966Total other comprehensive (loss) income$(31,881) $11,153 $(20,728) $4,551 $(1,585) $2,966             For the Three-Months Ended September 30 2013 2012 Pretax Amount Tax (Expense) Benefit Net of Tax Amount Pretax Amount Tax (Expense) Benefit Net of Tax Amount (dollars in thousands)Unrealized (losses) gains on securities:           Unrealized holding (losses) gains on securities arising during the period$(4,239) $1,487 $(2,752) $2,068 $(722) $1,346Non-credit related gains on securities not expected to be sold236 (82) 154 1,374 (481) 893Reclassification adjustment for gains on securities included in net income(229) 80 (149) (163) 57 (106)Total unrealized (losses) gains on securities(4,232) 1,485 (2,747) 3,279 (1,146) 2,133Total other comprehensive (loss) income$(4,232) $1,485 $(2,747) $3,279 $(1,146) $2,133 |
| Schedule of Accumulated Other Comprehensive Income (Loss)           | The following table details the change in components of OCI for the nine-months endedSeptember 30: 2013 2012 Securities Available for SalePost-Retirement ObligationAccumulated Other Comprehensive Income Securities Available for SalePost-Retirement ObligationAccumulated Other Comprehensive Income (dollars in thousands)Balance at December 31$1,121$138$1,259 $1,669$332$2,001Other comprehensive (loss) income before reclassification adjustment(23,786)—(23,786) 2,065—2,065Amounts reclassified from accumulated other comprehensive income (loss)3,058—3,058 901—901Net other comprehensive (loss) income during the period(20,728)—(20,728) 2,966—2,966Balance at September 30$(19,607)$138$(19,469) $4,635$332$4,967                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |

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| - 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=20435746&loc=SL7669686-108580
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| - Definition
Tabular disclosure of the net gain (loss) and net prior service cost or credit recognized in other comprehensive income (loss) for the period for pension plans and/or other employee benefit plans, and reclassification adjustments of other comprehensive income (loss) for the period, as those amounts, including amortization of the net transition asset or obligation, are recognized as components of net periodic benefit cost.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=21915506&loc=d3e1928-114920
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