Defined Benefit Pension Plans (Policies)	6 Months Ended
Defined Benefit Pension Plans (Policies)	Jun. 30, 2012
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]
Pension and Other Postretirement Plans Policy	The Corporation offers a tax-qualified defined benefit pension plan for the benefit of certain eligible employees. The pension plan was amended effective October 1, 2007 to freeze plan entry to new hires and rehires. Existing employees hired prior to October 1, 2007 continue to accrue benefits under the plan. Benefits are based on an employee’s years of service and compensation earned during the years of service. The plan is funded on a current basis, in compliance with the requirements of ERISA. The Corporation also has non-qualified retirement plans to provide supplemental retirement benefits to certain employees, as defined in the plans. The supplemental retirement plans provide eligible participants with an additional retirement benefit

Disclosure of accounting policy for pension and other postretirement benefit plans. This accounting policy may address (1) the types of plans sponsored by the entity, and the benefits provided by each plan (2) groups that participate in (or are covered by) each plan (3) how plan assets, liabilities and expenses are measured, including the use of any actuaries and (4) significant assumptions used by the entity to value plan assets and liabilities and how such assumptions are derived.

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