| **Supplemental Comprehensive Income Disclosures**                                      | 6 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
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| **Supplemental Comprehensive Income Disclosures [Abstract]**                           |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
| Schedule of Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block] | The following table details the change in components of OCI for the six months endedJune 30: 2014 2013 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$(20,868)$280$(20,588) $1,121$138$1,259Other comprehensive income (loss) before reclassification adjustment14,567—14,567 (17,976)—(17,976)Amounts reclassified from accumulated other comprehensive income (loss)(1)—(1) (5)—(5)Net other comprehensive income (loss) during the period14,566—14,566 (17,981)—(17,981)Balance at June 30$(6,302)$280$(6,022) $(16,860)$138$(16,722)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
| Supplemental Comprehensive Income Disclosures                                          | Supplemental Comprehensive Income DisclosuresThe 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.  For the Six Months Ended June 30, 2014 2013 Pretax Amount Tax (Expense) Benefit Net of Tax Amount Pretax Amount Tax (Expense) Benefit Net of Tax Amount (dollars in thousands)Unrealized gains (losses) on securities:           Unrealized holding gains (losses) on securities arising during the period$22,407 $(7,840) $14,567 $(27,641) $9,665 $(17,976)Reclassification adjustment for gains on securities included in net income(2) 1 (1) (8) 3 (5)Total unrealized gains (losses) on securities22,405 (7,839) 14,566 (27,649) 9,668 (17,981)Total other comprehensive income (loss)$22,405 $(7,839) $14,566 $(27,649) $9,668 $(17,981) For the Three Months Ended June 30, 2014 2013 Pretax Amount Tax (Expense) Benefit Net of Tax Amount Pretax Amount Tax (Expense) Benefit Net of Tax Amount (dollars in thousands)Unrealized gains (losses) on securities:           Unrealized holding gains (losses) on securities arising during the period$9,950 $(3,479) $6,471 $(25,230) $8,822 $(16,408)Reclassification adjustment for gains on securities included in net income(2) 1 (1) (4) 2 (2)Total unrealized gains (losses) on securities9,948 (3,478) 6,470 (25,234) 8,824 (16,410)Total other comprehensive income (loss)$9,948 $(3,478) $6,470 $(25,234) $8,824 $(16,410) The following table details the change in components of OCI for the six months endedJune 30: 2014 2013 Securities Available for SalePost-Retirement ObligationAccumulated Other Comprehensive Income Securities Available for SalePost-Retirement ObligationAccumulated Other Comprehensive Income (dollars in thousands)Balance at December 31$(20,868)$280$(20,588) $1,121$138$1,259Other comprehensive income (loss) before reclassification adjustment14,567—14,567 (17,976)—(17,976)Amounts reclassified from accumulated other comprehensive income (loss)(1)—(1) (5)—(5)Net other comprehensive income (loss) during the period14,566—14,566 (17,981)—(17,981)Balance at June 30$(6,302)$280$(6,022) $(16,860)$138$(16,722) |

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| - Definition
The entire disclosure for comprehensive income, which includes, but is not limited to, 1) the amount of income tax expense or benefit allocated to each component of other comprehensive income, including reclassification adjustments, 2) the reclassification adjustments for each classification of other comprehensive income and 3) the ending accumulated balances for each component of comprehensive income.
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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.
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