Allowance for Loan Losses (Policies)	9 Months Ended
Sep. 30, 2012
Receivables [Abstract]
Allowance for Loan Losses Policy	The allowance for loan losses is management's best estimate of inherent risk of loss in the loan portfolio as of the balance sheet date. The allowance is increased by provisions charged to earnings and by recoveries of amounts previously charged off, and is reduced by charge-offs on loans. The Corporation uses a methodology to systematically measure the amount of estimated loan loss exposure inherent in the loan portfolio for purposes of establishing a sufficient allowance for loan losses. The methodology includes three elements: (1) identification of loss allocations for individual loans deemed to be impaired, (2) loss allocation factors for non-impaired loans based on credit grade, loss experience, delinquency factors and other similar economic indicators, and (3) general loss allocations for other environmental factors, which is classified as “unallocated”. Periodic assessments and revisions to the loss allocation factors used in the assignment of loss exposure are made to appropriately reflect the analysis of migrational loss experience. The Corporation analyzes historical loss experience in the various portfolios over periods deemed to be relevant to the inherent risk of loss in the respective portfolios as of the balance sheet date. The Corporation adjusts the loss allocations for various factors it believes are not adequately presented in historical loss experience, including trends in real estate values, trends in rental rates on commercial real estate, consideration of general economic conditions and our assessments of credit risk associated with certain industries and an ongoing trend toward larger credit relationships. These factors are also evaluated taking into account the geographic location of the underlying loans. Revisions to loss allocation factors are not retroactively applied. Loss allocations for loans deemed to be impaired are measured on a discounted cash flow method based upon the loan's contractual effective interest rate, or at the loan's observable market price, or, if the loan is collateral dependent, at the fair value of the collateral less costs to sell. For collateral dependent loans, management may adjust appraised values to reflect estimated market value declines or apply other discounts to appraised values for unobservable factors resulting from its knowledge of circumstances associated with the property. Loss allocation factors are used for non-impaired loans based on credit grade, loss experience, delinquency factors and other similar credit quality indicators. Individual commercial loans and commercial mortgage loans not deemed to be impaired are evaluated using the internal rating system described in Note 5 under the caption “Credit Quality Indicators” and the application of loss allocation factors. The loan rating system and the related loss allocation factors take into consideration parameters including the borrower's financial condition, the borrower's performance with respect to loan terms, and the adequacy of collateral. Portfolios of more homogeneous populations of loans including the various categories of residential mortgages and consumer loans are analyzed as groups taking into account delinquency ratios and other indicators and our historical loss experience for each type of credit product. An additional unallocated allowance is maintained to allow for measurement imprecision attributable to uncertainty in the economic environment and ever changing conditions and to reflect management's consideration of qualitative and quantitative assessments of other environmental factors, including, but not limited to, conditions that may affect the collateral position such as environmental matters, tax liens, and regulatory changes affecting the foreclosure process, as well as conditions that may affect the ability of borrowers to meet debt service requirements. Because the methodology is based upon historical experience and trends, current economic data as well as management's judgment, factors may arise that result in different estimations. Significant factors that could give rise to changes in these estimates may include, but are not limited to, changes in economic conditions in our market area, concentration of risk, and declines in local property values. Adversely different conditions or assumptions could lead to increases in the allowance. In addition, various regulatory agencies periodically review the allowance for loan losses. Such agencies may require additions to the allowance based on their judgments about information available to them at the time of their examination.

The allowance for loan losses is management's best estimate of inherent risk of loss in the loan portfolio as of the balance sheet date. The allowance is increased by provisions charged to earnings and by recoveries of amounts previously charged off, and is reduced by charge-offs on loans. The Corporation uses a methodology to systematically measure the amount of estimated loan loss exposure inherent in the loan portfolio for purposes of establishing a sufficient allowance for loan losses. The methodology includes three elements: (1) identification of loss allocations for individual loans deemed to be impaired, (2) loss allocation factors for non-impaired loans based on credit grade, loss experience, delinquency factors and other similar economic indicators, and (3) general loss allocations for other environmental factors, which is classified as “unallocated”.

Periodic assessments and revisions to the loss allocation factors used in the assignment of loss exposure are made to appropriately reflect the analysis of migrational loss experience. The Corporation analyzes historical loss experience in the various portfolios over periods deemed to be relevant to the inherent risk of loss in the respective portfolios as of the balance sheet date. The Corporation adjusts the loss allocations for various factors it believes are not adequately presented in historical loss experience, including trends in real estate values, trends in rental rates on commercial real estate, consideration of general economic conditions and our assessments of credit risk associated with certain industries and an ongoing trend toward larger credit relationships. These factors are also evaluated taking into account the geographic location of the underlying loans. Revisions to loss allocation factors are not retroactively applied.

Loss allocations for loans deemed to be impaired are measured on a discounted cash flow method based upon the loan's contractual effective interest rate, or at the loan's observable market price, or, if the loan is collateral dependent, at the fair value of the collateral less costs to sell. For collateral dependent loans, management may adjust appraised values to reflect estimated market value declines or apply other discounts to appraised values for unobservable factors resulting from its knowledge of circumstances associated with the property.

Loss allocation factors are used for non-impaired loans based on credit grade, loss experience, delinquency factors and other similar credit quality indicators. Individual commercial loans and commercial mortgage loans not deemed to be impaired are evaluated using the internal rating system described in Note 5 under the caption “Credit Quality Indicators” and the application of loss allocation factors. The loan rating system and the related loss allocation factors take into consideration parameters including the borrower's financial condition, the borrower's performance with respect to loan terms, and the adequacy of collateral. Portfolios of more homogeneous populations of loans including the various categories of residential mortgages and consumer loans are analyzed as groups taking into account delinquency ratios and other indicators and our historical loss experience for each type of credit product.

An additional unallocated allowance is maintained to allow for measurement imprecision attributable to uncertainty in the economic environment and ever changing conditions and to reflect management's consideration of qualitative and quantitative assessments of other environmental factors, including, but not limited to, conditions that may affect the collateral position such as environmental matters, tax liens, and regulatory changes affecting the foreclosure process, as well as conditions that may affect the ability of borrowers to meet debt service requirements.

Because the methodology is based upon historical experience and trends, current economic data as well as management's judgment, factors may arise that result in different estimations. Significant factors that could give rise to changes in these estimates may include, but are not limited to, changes in economic conditions in our market area, concentration of risk, and declines in local property values. Adversely different conditions or assumptions could lead to increases in the allowance. In addition, various regulatory agencies periodically review the allowance for loan losses. Such agencies may require additions to the allowance based on their judgments about information available to them at the time of their examination.