| **Derivative Financial Instruments**                                    | 6 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               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| **Derivative Instruments and Hedging Activities Disclosure [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              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| Derivative Financial Instruments                                        | DERIVATIVE FINANCIAL INSTRUMENTS Risk Management Objective of Using DerivativesThe Corporation is exposed to certain risks arising from both its business operations and economic conditions.  The Corporation principally manages its exposures to a wide variety of business and operational risks through management of its core business activities.  The Corporation manages economic risks, including interest rate, liquidity, and credit risk, primarily by managing the amount, sources, and duration of its assets and liabilities and through the use of derivative financial instruments.  Specifically, the Corporation enters into derivative financial instruments to manage exposures that arise from business activities that result in the receipt or payment of future known and uncertain cash amounts, the value of which are determined by interest rates.  The Corporation’s derivative financial instruments are used to manage differences in the amount, timing, and duration of the Corporation’s known or expected cash payments principally related to certain variable-rate liabilities.  The Corporation also has derivatives that are a result of a service the Corporation provides to certain qualifying customers, and, therefore, are not used to manage interest rate risk in the Corporation’s assets or liabilities.  The Corporation manages a matched book with respect to its derivative instruments offered as a part of this service to its customers in order to minimize its net risk exposure resulting from such transactions.Cash Flow Hedges of Interest Rate RiskThe Corporation’s objectives in using interest rate derivatives are to add stability to interest expense and to manage its exposure to interest rate movements.  To accomplish these objectives, the Corporation primarily uses interest rate swaps and interest rate caps as part of its interest rate risk management strategy.  Interest rate swaps designated as cash flow hedges involve the payment of fixed amounts to a counterparty in exchange for the Corporation receiving variable payments over the life of the agreements without exchange of the underlying notional amount.  Interest rate caps designated as cash flow hedges involve the receipt of variable amounts from a counterparty if interest rates rise above the strike rate on the contract in exchange for an up-front premium.  As of June 30, 2016 and December 31, 2015, the Corporation had five interest rate swaps with a notional amount of $56.0 million and one interest rate cap with a notional amount of $13.0 million that were designated as cash flow hedges.  The effective portion of changes in the fair value of derivatives designated and that qualify as cash flow hedges is recorded in accumulated other comprehensive income and is subsequently reclassified into interest expense as interest payments are made on the Corporation’s variable-rate liabilities.  During the next twelve months, the Corporation expects to reclassify $1,274,000 from accumulated other comprehensive income to interest expense.During 2016, $26.0 million of the interest rate swaps and the $13.0 million interest rate cap were used to hedge the LIBOR-based variable cash outflows associated with existing trust preferred securities when the outflows converted from a fixed rate to variable rate in September of 2012.  In addition, the remaining $30.0 million of interest rate swaps were used to hedge the LIBOR-based variable cash outflows associated with three Federal Home Loan Bank advances.  The ineffective portion of the change in fair value of the derivatives is recognized directly in earnings.  During the six months ended June 30, 2016, and 2015, the Corporation did not recognize any ineffectiveness.Non-designated HedgesThe Corporation does not use derivatives for trading or speculative purposes.  Derivatives not designated as hedges are not speculative and result from a service the Corporation provides to certain customers.  The Corporation executes interest rate swaps with commercial banking customers to facilitate their respective risk management strategies.  Those interest rate swaps are simultaneously hedged by offsetting interest rate swaps that the Corporation executes with a third party, such that the Corporation minimizes its net risk exposure resulting from such transactions.  As the interest rate swaps associated with this program do not meet the strict hedge accounting requirements, changes in the fair value of both the customer swaps and the offsetting swaps are recognized directly in earnings.  As of June 30, 2016, the notional amount of customer-facing swaps was approximately $205,884,000.  This amount is offset with third party counterparties, as described above.Fair Values of Derivative Instruments on the Balance SheetThe table below presents the fair value of the Corporation’s derivative financial instruments, as well as their classification on the Balance Sheet, as of June 30, 2016, and December 31, 2015. Asset DerivativesLiability Derivatives June 30, 2016December 31, 2015June 30, 2016December 31, 2015 BalanceSheetLocationFairValueBalanceSheetLocationFairValueBalanceSheetLocationFairValueBalanceSheetLocationFairValueDerivatives designated as hedging instruments:        Interest rate contractsOther Assets$5Other Assets$36Other Liabilities$5,092Other Liabilities$2,921Derivatives not designated as hedging instruments:        Interest rate contractsOther Assets$11,971Other Assets$4,938Other Liabilities$12,669Other Liabilities$5,149The amount of gain (loss) recognized in other comprehensive income is included in the table below for the periods indicated.Derivatives in Cash Flow Hedging RelationshipsAmount of Gain (Loss) Recognized in Other Comprehensive Income on Derivative (Effective Portion)Three Months EndedSix Months EndedJune 30, 2016June 30, 2015June 30, 2016June 30, 2015Interest Rate Products$(813)$807$(2,767)$(469)Effect of Derivative Instruments on the Income StatementThe tables below present the effect of the Corporation’s derivative financial instruments on the Income Statement for the three and six months ended June 30, 2016, and 2015.Derivatives Not Designated asHedging Instruments underFASB ASC 815-10Location of Gain (Loss)Recognized Income onDerivativeAmount of Gain (Loss) Recognized in Income on DerivativeThree Months EndedJune 30, 2016Three Months Ended June 30, 2015Interest rate contractsOther income$(242)$156Derivatives Not Designated asHedging Instruments underFASB ASC 815-10Location of Gain (Loss)Recognized Income onDerivativeAmount of Gain (Loss) Recognized in Income on DerivativeSix Months Ended June 30, 2016Six Months Ended June 30, 2015Interest rate contractsOther income$(488)$55The amount of gain (loss) reclassified from other comprehensive income into income is included in the table below for the periods indicated.Derivatives Designated asHedging Instruments underFASB ASC 815-10Location of Gain (Loss)Recognized Income onDerivativeAmount of Gain (Loss) Reclassed from Other Comprehensive Income into Income  (Effective Portion)Three Months EndedJune 30, 2016Three Months Ended June 30, 2015Interest rate contractsInterest Expense(318)(358)Derivatives Designated asHedging Instruments underFASB ASC 815-10Location of Gain (Loss)Recognized Income onDerivativeAmount of Gain (Loss) Reclassed from Other Comprehensive Income into Income  (Effective Portion)Six Months EndedJune 30, 2016Six Months Ended June 30, 2015Interest rate contractsInterest Expense$(642)$(712)The Corporation’s exposure to credit risk occurs because of nonperformance by its counterparties.  The counterparties approved by the Corporation are usually financial institutions, which are well capitalized and have credit ratings through Moody’s and/or Standard & Poor’s at or above investment grade.  The level of risk is monitored by performing quarterly financial reviews, comparing mark-to-mark values with policy limitations, monitoring credit ratings and pledging of collateral.Credit-risk-related Contingent FeaturesThe Corporation has agreements with certain of its derivative counterparties that contain a provision where if the Corporation fails to maintain its status as a well or adequately capitalized institution, then the Corporation could be required to terminate or fully collateralize all outstanding derivative contracts.The Corporation also has agreements with certain of its derivative counterparties that contain a provision where if the Corporation defaults on any of its indebtedness, including default where repayment of the indebtedness has not been accelerated by the lender, the Corporation could also be declared in default on its derivative obligations.  As of June 30, 2016, the termination value of derivatives in a net liability position related to these agreements was $18,063,000.  As of June 30, 2016, the Corporation had minimum collateral posting thresholds with certain of its derivative counterparties and had posted collateral of $18,011,000.  If the Corporation had breached any of these provisions at June 30, 2016, it could have been required to settle its obligations under the agreements at their termination value. |

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| - Definition
The entire disclosure for derivative instruments and hedging activities including, but not limited to, risk management strategies, non-hedging derivative instruments, assets, liabilities, revenue and expenses, and methodologies and assumptions used in determining the amounts.
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