| **Pension and Other Post Retirement Benefit Plans (Tables)**                                                                                        | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
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| **Compensation and Retirement Disclosure [Abstract]**                                                                                               |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
| Schedule of Changes in Benefit Obligation, Changes in Plan Assets and the Funded Status of the Pension Plan and Other Post Retirement Benefit Plans | The table below sets forth the plans’ funded status and amounts recognized in the consolidated balance sheet at December 31, using measurement dates of December 31, 2012 and December 31, 2011. 2012 2011Change in benefit obligation   Benefit obligation at beginning of year$68,769 $61,422Service Cost161 252Interest Cost2,990 3,208Actuarial Loss (Gain)3,168 7,346Benefits paid(5,922) (3,459)Benefit obligation at end of year69,166 68,769Change in plan assets   Fair value of plan assets at beginning of year62,078 63,275Actual return on plan assets6,141 1,726Employer contributions568 536Benefits Paid(5,922) (3,459)End of Year62,865 62,078Funded Status at End of Year$(6,301) $(6,691)Assets and Liabilities Recognized in the Balance Sheets:   Deferred Tax Asset$9,200 $10,928Liabilities$6,301 $6,691Amounts Recognized in Accumulated Other Comprehensive Income Not Yet Recognized as Components of Net Periodic Benefit Cost Consist of:   Accumulated Loss$(17,085) $(16,310)Prior Service Credit(41) (56) $(17,126) $(16,366) |
| Schedule of Accumulated Benefit Obligations in Excess of Fair Value of Plan Assets                                                                  | Information for for pension plans with an accumulated benefit obligation in excess of plan assets is included in the table below.  December 31, 2012 December 31, 2011Projected Benefit Obligation$69,166 $68,769Accumulated Benefit Obligation$69,139 $68,729Fair Value of Plan Assets$62,865 $62,078                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
| Schedule of Net Periodic Pension Costs                                                                                                              | The following table shows the components of net periodic pension costs: December 31, 2012 December 31, 2011Service Cost$161 $252Interest Cost2,990 3,208Expected Return on Plan Assets(4,216) (4,313)Amortization of Prior Service Costs25 25Amortization of Net Loss2,207 1,129Net Periodic Pension Cost$1,167 $301                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
| Schedule of Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income, Net of Tax                                                | Other changes in plan assets and benefit obligations recognized in other comprehensive income: December 31, 2012 December 31, 2011Net Periodic Pension Cost$1,167 $301Net gain (loss)1,242 9,933Actuarial gain (loss)(2,207) (1,129)Amortization of prior service (cost) credit(25) (25)Total Recognized in Other Comprehensive Income(990) 8,779Total Recognized in NPPC and OCI$177 $9,080                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
| Schedule of Amounts in Accumulated Other Comprehensive Income (Loss) to be Recognized over Next Fiscal Year                                         | The estimated net loss and transition obligation for the defined benefit pension plans that will be amortized from accumulated other comprehensive income into net periodic pension cost over the next fiscal year are:December 31, 2012December 31, 2011Amortization of Net Loss$(2,158)$(2,319)Amortization of Prior Service Cost(25)(25)Total$(2,183)$(2,344)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
| Schedule of Assumptions Used                                                                                                                        | Significant assumptions include: December 31, 2012 December 31, 2011Weighted-average Assumptions Used to Determine Benefit Obligation:   Discount Rate4.00% 4.50%Rate of Compensation Increase for accruing active participants3.00% 4.00%Weighted-average Assumptions Used to Determine Benefit Cost:   Discount Rate4.50% 5.40%Expected Return on Plan Assets7.00% 7.00%Rate of Compensation Increase for accruing active participants4.00% 4.00%                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
| Schedule of Expected Benefit Payments                                                                                                               | The minimum contribution required in 2013 will likely be zero but the Corporation may decide to make a discretionary contribution during the year.2013$3,98420144,11020154,23620164,21920174,201After 201721,414 $42,164                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
| Schedule of Allocation of Plan Assets                                                                                                               | Plan assets are re-balanced quarterly. At December 31, 2012 and 2011, plan assets by category are as follows: December 31, 2012December 31, 2011 ActualTargetActualTargetCash and cash equivalents1.3%3.0%3.2%3.0%Equity securities53.751.049.751.0Debt securities43.044.045.544.0Alternative investments2.02.01.62.0 100.0%100.0%100.0%100.0%There are no assets classified within Level 3 of the hierarchy at December 31, 2012.  Fair Value Measurements Using   Quoted Prices inActive Markets forIdentical Assets Significant Other Observable Inputs SignificantUnobservableInputsDecember 31, 2012Fair Value(Level 1)(Level 2)(Level 3)Cash & Cash Equivalents$795$795Corporate Bonds and Notes6,1576,157Government Agency and Municipal Bonds and Notes8,642$8,642Certificates of Deposit357357Preferred Stock5252Party-in-Interest Investments   Common Stock898898Common Bond Fund4,0754,075Common Equity Fund4,4954,495Mutual FundsTaxable Bond7,4097,409Large Cap Equity16,16616,166Mid Cap Equity6,7726,772Small Cap Equity2,6402,640International Equity3,1783,178Specialty Alternative Equity1,2291,229                         |

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| - Definition
Tabular disclosure of accumulated benefit obligations and fair values of plan assets of pension plans and/or other employee benefit plans where the accumulated benefit obligation exceeds the fair value of plan assets.
+ References
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| - Definition
Tabular disclosure of the major categories of plan assets of pension plans and/or other employee benefit plans.  This information may include, but is not limited to, the target allocation of plan assets, the fair value of each major category of plan assets, and the level within the fair value hierarchy in which the fair value measurements fall.
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| - Definition
Tabular disclosure of the amounts related to pension plans and/or other employee benefit plans in accumulated other comprehensive income (loss) expected to be recognized as components of net periodic benefit cost over the next fiscal year, including the net gain (loss), net prior service cost or credit, and net transition asset or obligation.
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| - Definition
Tabular disclosure of the assumptions used to determine for pension plans and/or other employee benefit plans the benefit obligation and net benefit cost, including assumed discount rates, rate increase in compensation increase, and expected long-term rates of return on plan assets.
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| - Definition
Tabular disclosure of the changes in plan assets and benefit obligations recognized in other comprehensive income (loss) during the period.
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| - Definition
Tabular disclosure of one or more of the entity's defined benefit pension plans or one or more other defined benefit postretirement plans, separately for pension plans and other postretirement benefit plans including the entity's schedule of fair value of plan assets for defined benefit or other postretirement plans.
+ References
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| - Definition
Tabular disclosure of benefits expected to be paid by pension plans and/or other employee benefit plans in each of the next five fiscal years and in the aggregate for the five fiscal years thereafter.
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| - Definition
Tabular disclosure of the components of net benefit costs for pension plans and/or other employee benefit plans including service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) recognized due to settlements or curtailments.
+ References
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