| **Investment Securities**                              | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               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| **Investments, Debt and Equity Securities [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                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| Investment Securities                                  | INVESTMENT SECURITIESThe amortized cost, gross unrealized gains, gross unrealized losses and approximate market value of the investment securities at the dates indicated were: Amortized CostGross Unrealized GainsGross Unrealized LossesFair ValueAvailable for sale at December 31, 2012       U.S. Government-sponsored agency securities$4,475$165$4,640State and municipal148,18710,025$18158,194U.S. Government-sponsored mortgage-backed securities337,63110,99446348,579Corporate obligations6,1055,881224Equity securities1,7061,706Total available for sale498,10421,1845,945513,343Held to maturity at December 31, 2012 State and municipal117,2275,4891122,715U.S. Government-sponsored mortgage-backed securities243,79311,68115255,459Total held to maturity361,02017,17016378,174Total Investment Securities$859,124$38,354$5,961$891,517        Available for sale at December 31, 2011       U.S. Government-sponsored agency securities$99 $18   $117State and municipal136,857 10,496   147,353U.S. Government-sponsored mortgage-backed securities358,928 10,086 $16 368,998Corporate obligations5,765   5,572 193Equity securities1,830     1,830Total available for sale503,479 20,600 5,588 518,491Held to maturity at December 31, 2011       State and municipal120,171 3,785   123,956U.S. Government-sponsored mortgage-backed securities307,738 10,775   318,513Total held to maturity427,909 14,560   442,469Total Investment Securities$931,388 $35,160 $5,588 $960,960  Certain investments in debt securities are reported in the financial statements at an amount less than their historical cost.  The historical cost of these investments totaled $22,999,000 and $11,925,000 at December 31, 2012 and 2011, respectively.  Total fair value of these investments was $17,038,000  and $6,339,000, which is approximately 1.9  and  0.7 percent of the Corporation's available for sale and held to maturity investment portfolio at December 31, 2012 and 2011, respectively.Except as discussed below, management believes the declines in fair value for these securities are temporary. Should the impairment of any of these securities become other-than-temporary, the cost basis of the investment will be reduced and the resulting loss recognized in net income in the period the other-than-temporary impairment (“OTTI”) is identified.The Corporation’s management has evaluated all securities with unrealized losses for OTTI as of December 31, 2012.  The evaluations are based on the nature of the securities, the extent and duration of the loss and the intent and ability of the Corporation to hold these securities either to maturity or through the expected recovery period.The current unrealized losses are primarily concentrated within trust preferred securities held by the Corporation.  Such investments have an amortized cost of $6.1 million and a fair value of $194,000, which is less than 1 percent of the Corporation’s entire investment portfolio.  On all but one small pool investment, the Corporation utilized Moody’s to determine their fair value.In determining the fair value of the trust preferred securities, the Corporation utilizes a third party for portfolio accounting services, including market value input.  The Corporation has obtained an understanding of what inputs are being used by the vendor in pricing the portfolio and how the vendor was classifying these securities based upon these inputs.  From these discussions, the Corporation’s management is comfortable that the classifications are proper.  The Corporation has gained trust in the data for two reasons:  (a) independent spot testing of the data is conducted by the Corporation through obtaining market quotes from various brokers on a periodic basis and (b) actual gains or loss resulting from the sale of certain securities has proven the data to be accurate over time.   Discount rates used in the cash flow analysis on these variable rate securities were those margins in effect at the inception of the security added to the appropriate three-month LIBOR spot rate obtained from the forward LIBOR curve used to project future principal and interest payments. These spreads ranged from .85 percent to 1.57 percent spread over LIBOR.U.S. Government-Sponsored Mortgage-Backed Securities The unrealized losses on the Corporation's investment in mortgage-backed securities were a result of interest rate changes. The Corporation expects to recover the amortized cost basis over the term of the securities.  Because the decline in market value is attributable to changes in interest rates and not credit quality, and because the Corporation does not intend to sell the investments and it is not more likely than not, the Corporation will be required to sell the investments before recovery of their amortized cost basis, which may be maturity, the Corporation does not consider those investments to be other-than-temporarily impaired at December 31, 2012.  As noted in the table above, the mortgage-backed securities portfolio contains unrealized losses of $46,000 on four securities and $15,000 on one security in the available for sale and held to maturity portfolios, respectively.  All these securities are issued by a government-sponsored entity.State and Political Subdivisions The unrealized losses on the Corporation's investments in securities of state and political subdivisions were caused by interest rate increases. The contractual terms of those investments do not permit the issuer to settle the securities at a price less than the amortized cost basis of the investments. Because the Corporation does not intend to sell the investments and it is not more likely than not the Corporation will be required to sell the investments before recovery of their amortized cost basis, which may be maturity, the Corporation does not consider those investments to be other-than-temporarily impaired at December 31, 2012.  As noted in the table above, the state and political subdivision securities portfolio contains unrealized losses of $18,000 on eight securities and $1,000 on four  securities in the available for sale and held to maturity portfolios respectively. Corporate Obligations The Corporation’s unrealized losses on trust preferred securities total $5.9 million on a book value of $6.1 million. The decline in value is attributable to temporary illiquidity and the financial crisis affecting these markets coupled with the potential credit loss resulting from the adverse change in expected cash flows. Due to the illiquidity in the market, it is unlikely that the Corporation would be able to recover its investment in these securities if the Corporation sold the securities at this time. Management has analyzed the cash flow characteristics of the securities and this analysis included utilizing the most recent trustee reports and any other relevant market information, including announcements of deferrals or defaults of trust preferred securities.  The Corporation compared expected discounted cash flows, based on performance indicators of the underlying assets in the security, to the carrying value of the investment to determine if OTTI existed.  The Corporation does not consider the remainder of the investment securities, which are classified as Level 3 inputs in the fair value hierarchy, to be other-than-temporarily impaired at December 31, 2012.  The Corporation does not intend to sell the investment, and it is not more likely than not that the Corporation will be required to sell the investment before recovery of its new, lower amortized cost basis, which may be maturity.Certain Losses Recognized on InvestmentsCertain debt securities have experienced fair value deterioration due to credit losses and other market factors.  The following table provides information about debt securities for which only a credit loss was recognized in income and other losses are recorded in other comprehensive income. Accumulated Credit Losses in  Accumulated Credit Losses in  2012 2011Credit losses on debt securities held:   Balance, January 1$11,355 $10,955Additions related to other-than-temporary losses not previously recognized 400Balance, December 31$11,355 $11,355The following table shows the Corporation’s gross unrealized losses and fair value, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position at December 31, 2012 and 2011:  Fair ValueGross Unrealized LossesFair ValueGross Unrealized LossesFair ValueGross Unrealized Losses Less than 12 Months12 Months or LongerTotalTemporarily Impaired Investment      Securities at December 31, 2012      State and municipal$4,524$19$4,524$19U.S. Government-sponsored mortgage-backed securities12,3206112,32061Corporate obligations$194$5,8811945,881Total Temporarily Impaired Investment Securities$16,844$80$194$5,881$17,038$5,961            Temporarily Impaired Investment      Securities at December 31, 2011      U.S. Government-sponsored mortgage-backed securities$6,176$16$6,176$16Corporate obligations$163$5,5721635,572Total Temporarily Impaired Investment Securities$6,176$16$163$5,572$6,339$5,588 The amortized cost and fair value of securities available for sale and held to maturity at December 31, 2012 by contractual maturity are shown below.  Expected maturities will differ from contractual maturities because issuers may have the right to call or prepay obligations with or without call or prepayment penalties. Available for SaleHeld to Maturity Amortized CostFair ValueAmortized CostFair ValueMaturity Distribution at December 31, 2012    Due in one year or less$4,366$4,415$2,590$2,594Due after one through five years14,76415,4682,5542,575Due after five through ten years54,14857,44257,81160,163Due after ten years85,48985,73354,27257,383 $158,767$163,058$117,227$122,715U.S. Government-sponsored mortgage-backed securities337,631348,579243,793255,459Equity securities1,7061,706Total Investment Securities$498,104$513,343$361,020$378,174  Securities with a carrying value of approximately $335,775,000, $299,478,000 and $271,091,000  were pledged at December 31, 2012, 2011 and 2010, respectively, to secure certain deposits and securities sold under repurchase agreements, and for other purposes as permitted or required by law.Gross gains of $2,389,000, $2,439,000 and $3,636,000 in 2012, 2011 and 2010, respectively, and gross losses of $0, $0 and $230,000 in 2012, 2011 and 2010, respectively, were realized on sales of available for sale securities. |

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The entire disclosure for  investments in certain debt and equity securities.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=6872113&loc=d3e27405-111563Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6379141&loc=d3e15032-111544Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 3, 19, 20, 21, 22, 137 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.  This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 320 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6957658&loc=d3e62557-112803Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -Glossary Equity Security -URI http://asc.fasb.org/extlink&oid=6511694Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -Glossary Debt Security -URI http://asc.fasb.org/extlink&oid=6509901Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6872113&loc=d3e27232-111563Reference 8: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -URI http://asc.fasb.org/extlink&oid=6872113&loc=d3e27357-111563Reference 9: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6872113&loc=d3e27161-111563Reference 10: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=6872113&loc=d3e27290-111563
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