Summary of Significant Accounting Policies (Notes)	12 Months Ended
Dec. 31, 2011
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Organization Columbia Banking System, Inc. (the “Corporation”) is the holding company for Columbia State Bank (the “Bank”). The Bank provides a full range of financial services through 102 branch locations, including 77 in the State of Washington and 25 in Oregon. Because the Bank comprises substantially all of the business of the Corporation, references to the “Company” mean the Corporation and the Bank together. The Corporation is approved as a bank holding company pursuant to the Gramm-Leach-Bliley Act of 1999. The Company’s accounting and reporting policies conform to accounting principles generally accepted in the United States of America (“GAAP”) and practices in the financial services industry. To prepare the financial statements in conformity with GAAP, management must make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements, and income and expenses during the reporting period. Circumstances and events that differ significantly from those underlying our estimates and assumptions could cause actual financial results to differ from our estimates. The most significant estimates included in the financial statements relate to the allowance for loan and lease losses, business combinations, acquired impaired loans, Federal Deposit Insurance Corporation loss sharing asset and goodwill impairment. The Company has applied its accounting policies and estimation methods consistently in all periods presented in these financial statements (to the periods in which they applied), except for certain estimates related to the measurement of expected future cash flows on acquired impaired loans. For those certain estimates, in 2011 the Company began utilizing actual historical loan data rather than industry data, which had been utilized in 2010. The results of operations reflect any adjustments, all of which are of a normal recurring nature, and which, in the opinion of management, are necessary for a fair presentation of the results of the periods presented. Consolidation The consolidated financial statements of the Company include the accounts of the Corporation and the Bank. Intercompany balances and transactions have been eliminated in consolidation. Cash and cash equivalents Cash and cash equivalents include cash and due from banks, and interest bearing balances due from correspondent banks and the Federal Reserve Bank. Cash and cash equivalents have a maturity of 90 days or less at the time of purchase. Securities Securities are classified based on management’s intention on the date of purchase. All securities are classified as available for sale and are presented at fair value. Unrealized gains or losses on securities available for sale are excluded from net income but are included as separate components of other comprehensive income, net of taxes. Purchase premiums or discounts on securities available for sale are amortized or accreted into income using the interest method over the terms of the individual securities. The Company performs a quarterly assessment to determine whether a decline in fair value below amortized cost is other-than-temporary. Amortized cost includes adjustments made to the cost of an investment for accretion, amortization, collection of cash and previous other-than temporary impairment recognized in earnings. Other-than-temporary impairment exists when it is probable that the Company will be unable to recover the entire amortized cost basis of the security. If the decline in fair value is judged to be other than temporary, the security is written down to fair value which becomes the new cost basis and an impairment loss is recognized. In performing the quarterly assessment for debt securities, management considers whether or not the Company expects to recover the entire amortized cost basis of the security. In addition, management must determine its position with respect to its intent to sell the security and whether it is more likely than not that it will not have to sell the security before recovery of its cost basis. The total amount recognized in earnings when there are credit losses associated with an impaired debt security and management asserts that it does not have the intent to sell the security and it is more likely than not that it will not have to sell the security before recovery of its cost basis is separated into (a) the amount representing a credit loss and (b) the amount related to non-credit factors. The amount of impairment related to credit losses is recognized in earnings. The credit loss component of other-than-temporary impairment, representing an increase in credit risk, is determined by the Company using its best estimate of the present value of cash flows expected to be collected from the debt security. The amount of impairment related to non-credit factors is recognized in other comprehensive income. The previous cost basis less impairment recognized in earnings becomes the new cost basis of the security and is not adjusted for subsequent recoveries in fair value. However, the difference between the new amortized cost basis and the cash flows expected to be collected is accreted as interest income. The total other-than-temporary impairment is presented in the consolidated statements of income with a reduction for the amount of other-than-temporary impairment that is recognized in other comprehensive income, if any. Realized gains or losses on sales of securities available for sale are recorded using the specific identification method. Federal Home Loan Bank Stock The Company’s investment in Federal Home Loan Bank (“FHLB”) stock is carried at par value because the shares can only be redeemed with the FHLB at par. The Company is required to maintain a minimum level of investment in FHLB stock based on specific percentages of its outstanding mortgages and FHLB advances. Stock redemptions are at the discretion of the FHLB or of the Company, upon five years’ prior notice for FHLB Class B stock or six months notice for FHLB Class A stock to the FHLB. FHLB stock is carried at cost and is subject to recoverability testing per the Financial Services—Depository and Lending topic of the FASB Accounting Standards Codification (“ASC”). Loans Loans are generally carried at the unpaid principal balance, net of premiums, unearned discounts and net deferred loan fees. Net deferred loan fees include deferred unamortized fees less direct incremental loan origination costs. Net deferred loan fees, premiums and unearned discounts on loans are recognized in interest income using either the interest method or straight-line method over the terms of the loans, adjusted for actual prepayments. Interest income is accrued as earned. Fees related to lending activities other than the origination or purchase of loans are recognized as noninterest income during the period the related services are performed. Nonaccrual loans—Loans are placed on nonaccrual status when a loan becomes contractually past due 90 days with respect to interest or principal unless the loan is both well secured and in the process of collection, or if full collection of interest or principal becomes uncertain. When a loan is placed on nonaccrual status, any accrued and unpaid interest receivable is reversed and the recognition of net deferred loan fees, premiums and unearned discounts ceases. Thereafter, interest collected on the loan is accounted for on the cash collection or cost recovery method until qualifying for return to accrual status. Generally, a loan may be returned to accrual status when the delinquent principal and interest are brought current in accordance with the terms of the loan agreement and future payments are reasonably assured. Impaired loans—Loans are considered impaired when based on current information and events, it is probable that the Company will be unable to collect all amounts due according to the contractual terms of the loan agreement or when a loan has been modified in a troubled debt restructuring. The assessment for impairment occurs when and while such loans are designated as classified per the Company’s internal risk rating system or when and while such loans are on nonaccrual. All nonaccrual loans greater than $250,000 are considered impaired and analyzed individually on a quarterly basis. Classified loans with an outstanding balance greater than $250,000 are evaluated for potential impairment on a quarterly basis. When a loan with unique risk characteristics has been identified as being impaired, the amount of impairment will be measured by the Company using discounted cash flows, except when it is determined that the primary (remaining) source of repayment for the loan is the operation or liquidation of the underlying collateral. In these cases, the current fair value of the collateral, reduced by costs to sell, will be used in place of discounted cash flows. As a final alternative, the observable market price of the debt may be used to assess impairment. Predominantly, the Company uses the fair value of collateral approach based upon a reliable valuation. When the measurement of the impaired loan is less than the recorded amount of the loan, an impairment is recognized by recording a charge-off to the allowance for loan and lease losses or by designating a specific reserve. The Company’s policy is to record cash receipts received on impaired loans first as reductions to principal and then to interest income. Restructured Loans—A loan is classified as a troubled debt restructuring when a borrower is experiencing financial difficulties that lead to a restructuring of the loan, and the Company grants concessions to the borrower in the restructuring that it would not otherwise consider. These concessions may include interest rate reductions, principal forgiveness, extension of maturity date and other actions intended to minimize potential losses. Generally, a nonaccrual loan that is restructured remains on nonaccrual status for a period of six months to demonstrate that the borrower can meet the restructured terms. If the borrower's performance under the new terms is not reasonably assured, the loan remains classified as a nonaccrual loan. Acquired Impaired Loans—Loans acquired with evidence of credit deterioration since origination for which it is probable that all contractually required payments will not be collected are accounted for under Accounting Standards Codification (“ASC”) 310-30, Loans and Debt Securities Acquired with Deteriorated Credit Quality, formerly SOP 03-3 Accounting for Certain Loans or Debt Securities Acquired in a Transfer. In addition, because of the significant discounts associated with certain of the acquired loan portfolios, the Company elected to account for those certain acquired loans under ASC 310-30. In situations where such loans have similar risk characteristics, loans are aggregated into pools to estimate cash flows. A pool is accounted for as a single asset with a single interest rate, cumulative loss rate and cash flow expectation. Expected cash flows at the acquisition date in excess of the fair value of loans are considered to be accretable yield, which is recognized as interest income over the life of the loan pool using a level yield method if the timing and amount of the future cash flows of the pool is reasonably estimable. Subsequent to the acquisition date, any increases in cash flow over those expected at purchase date in excess of fair value are recorded as interest income prospectively. Any subsequent decreases in cash flow over those expected at purchase date due to credit deterioration are recognized by recording an allowance for losses on covered loans. Any disposals of loans, including sales of loans, payments in full or foreclosures result in the removal of the loan from the loan pool at the carrying amount. Covered Loans—The term covered loans refers to acquired loans that are covered under a loss-sharing agreement with the FDIC. Substantially all covered loans are accounted for under ASC 310-30. See Acquired Impaired Loans for further discussion. Unfunded loan commitments—Unfunded commitments are generally related to providing credit facilities to clients of the Bank and are not actively traded financial instruments. These unfunded commitments are disclosed as financial instruments with off-balance sheet risk in Note 17 in the Notes to Consolidated Financial Statements. Allowance for Loan and Lease Losses The Company accounts for the credit risk associated with lending activities through its allowance for loan and lease losses and provision for loan and lease losses. The provision is the expense recognized in the consolidated statements of income to adjust the allowance to the levels deemed appropriate by management, as determined through application of the Company’s allowance methodology procedures. The provision for loan and lease losses reflects management’s judgment of the adequacy of the allowance for loan and lease losses. Loan and lease losses are charged against the allowance when management believes the collectability of a loan balance is unlikely. Subsequent recoveries, if any, are credited to the allowance. The allowance for loan and lease losses is evaluated on a regular basis by management and is based upon management’s periodic review of the collectability of the loans in light of historical experience, the nature and volume of the loan portfolio, adverse situations that may affect the borrower’s ability to repay, estimated value of any underlying collateral and prevailing economic conditions. This evaluation is inherently subjective as it requires estimates that are susceptible to significant revision as more information becomes available. The allowance consists of general, specific, and unallocated components. The general component covers loans not specifically measured for impairment and is based on historical loss experience adjusted for qualitative factors. The specific component relates to loans that are impaired. For impaired loans an allowance is established when the discounted cash flows (or collateral value or observable market price) of the impaired loan is lower than the carrying value of that loan. The unallocated allowance provides for other credit losses inherent in the Company’s loan portfolio that may not have been contemplated in the general and specific components of the allowance. This unallocated amount generally comprises less than 5% of the allowance. The unallocated amount is reviewed periodically based on trends in credit losses, the results of credit reviews and overall economic trends. Allowance for Unfunded Commitments and Letters of Credit The allowance for unfunded commitments is maintained at a level believed by management to be sufficient to absorb estimated probable losses related to these unfunded credit facilities. The determination of the adequacy of the allowance is based on periodic evaluations of the unfunded credit facilities including an assessment of the probability of commitment usage, credit risk factors for loans outstanding to these same customers, and the terms and expiration dates of the unfunded credit facilities. The allowance for unfunded commitments is included in other liabilities on the consolidated balance sheets, with changes to the balance charged against noninterest expense. Allowance for Loan Losses on Covered Loans The Company updates its cash flow projections for covered loans accounted for under ASC 310-30 on a quarterly basis. Assumptions utilized in this process include projections related to probability of default, loss severity, prepayment and recovery lag. Projections related to probability of default and prepayment are calculated utilizing a loan migration analysis. The loan migration analysis is a matrix of probability that specifies the probability of a loan pool transitioning into a particular delinquency state given its delinquency state at the re-measurement date. Loss severity factors are based upon actual charge-off data within the loan pools and recovery lags are based upon the collateral within the loan pools. Any decreases in expected cash flows after the acquisition date and subsequent measurement periods are recognized by recording a provision for loan losses. See Acquired Impaired Loans for further discussion. Premises and Equipment Land, buildings, leasehold improvements and equipment are stated at cost less accumulated depreciation and amortization. Buildings and equipment are depreciated over their estimated useful lives using the straight-line method. Leasehold improvements are amortized over the shorter of their useful lives or lease terms. Gains or losses on dispositions are reflected in current operations. Expenditures for improvements and major renewals are capitalized, and ordinary maintenance, repairs and small purchases are charged to operating expenses. Software Capitalized software is stated at cost, less accumulated amortization. Amortization is computed on a straight-line basis and charged to expense over the estimated useful life of the software which is generally three years. Capitalized software is included in Premises and equipment, net in the Consolidated Balance Sheets. Other Real Estate Owned Other real estate owned (“OREO”) is composed of real estate acquired in satisfaction of loans. Properties acquired by foreclosure or deed in lieu of foreclosure are transferred to OREO and are recorded at fair value less estimated costs to sell, at the date of transfer of the property. If the carrying value exceeds the fair value at the time of the transfer, the difference is charged to the allowance for loan and lease losses. The fair value of the OREO property is based upon current appraisal. Losses that result from the ongoing periodic valuation of these properties are charged to the net cost of operation of OREO in the period in which they are identified. Improvements to the OREO are capitalized and holding costs are charged to the net cost of operation of OREO as incurred. Covered OREO—Covered OREO includes acquired OREO that is covered under a loss-sharing agreement with the FDIC. These assets were recorded at their fair value on acquisition date. Covered OREO is reported in Other real estate owned in the Consolidated Balance Sheets. Covered OREO is reported exclusive of expected reimbursement cash flows from the FDIC. Upon transferring covered loan collateral to covered OREO status, valuation adjustments arising from acquisition accounting on the related loan are also transferred to covered OREO. Valuation adjustments arising from acquisition accounting on covered OREO result in a reduction of the covered OREO carrying amount and a corresponding increase in the expected FDIC reimbursement, with the estimated net loss to the Company, if any, charged against earnings. FDIC Loss-sharing Asset The acquisition date fair value of the reimbursement the Company expected to receive from the FDIC under loss-sharing agreements was recorded in the FDIC loss-sharing asset on the Consolidated Balance Sheet. Subsequent to initial recognition, the FDIC loss-sharing asset is reviewed quarterly and adjusted for any changes in expected cash flows. These adjustments are measured on the same basis as the related covered assets. Any decrease in expected cash flows due to an increase in expected credit losses will increase the FDIC loss-sharing asset and any increase in expected future cash flows due to a decrease in expected credit losses will decrease the FDIC loss-sharing asset. Increases and decreases to the FDIC loss-sharing asset are recorded as adjustments to noninterest income. Goodwill and Intangibles Net assets of companies acquired in purchase transactions are recorded at fair value at the date of acquisition. Identified intangibles are amortized on an accelerated basis over the period benefited. Goodwill is not amortized but is reviewed for potential impairment during the third quarter on an annual basis or, more frequently, if events or circumstances indicate a potential impairment, at the reporting unit level. A reporting unit is an operating segment or one level below an operating segment for which discrete financial information is available and regularly reviewed by management. If the fair value of the reporting unit, including goodwill, is determined to be less than the carrying amount of the reporting unit, a further test is required to measure the amount of impairment. If an impairment loss exists, the carrying amount of goodwill is adjusted to a new cost basis. Subsequent reversal of a previously recognized goodwill impairment loss is prohibited. Intangible assets are evaluated for impairment if events and circumstances indicate a possible impairment. Such evaluation of other intangible assets is based on undiscounted cash flow projections. At December 31, 2011, intangible assets included on the consolidated balance sheets consist of a core deposit intangible amortized using an accelerated method with an original estimated life of approximately 10 years. Income Taxes The provision for income taxes includes current and deferred income tax expense on net income adjusted for permanent and temporary differences such as interest income on state and municipal securities and affordable housing credits. Deferred tax assets and liabilities are recognized for the expected future tax consequences of existing temporary differences between the financial reporting and tax reporting basis of assets and liabilities using enacted tax laws and rates. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. On a quarterly basis, management evaluates deferred tax assets to determine if these tax benefits are expected to be realized in future periods. This determination is based on facts and circumstances, including the Company’s current and future tax outlook. To the extent a deferred tax asset is no longer considered “more likely than not” to be realized, a valuation allowance is established. Advertising Advertising costs are generally expensed as incurred. Earnings per Common Share The Company calculates earnings per common share (“EPS”) using the two-class method in accordance with the Earnings per Share topic of the FASB ASC. The two-class method requires the Company to present EPS as if all of the earnings for the period are distributed to common shareholders and any participating securities, regardless of whether any actual dividends or distributions are made. Under authoritative guidance, all outstanding unvested share-based payment awards that contain rights to nonforfeitable dividends are considered participating securities. The Company grants restricted shares under a share-based compensation plan that qualifies as participating securities. Restricted shares issued under the Company’s share-based compensation plan are entitled to dividends at the same rate as common stock. Basic EPS are computed by dividing distributed and undistributed earnings available to common shareholders by the weighted average number of common shares outstanding for the period. Distributed and undistributed earnings available to common shareholders represent net income reduced by preferred stock dividends and distributed and undistributed earnings available to participating securities. Common shares outstanding include common stock and vested restricted stock awards. Diluted EPS reflect the assumed conversion of all potential dilutive securities. Share-Based Payment The Company accounts for stock options and stock awards in accordance with the Compensation—Stock Compensation topic of the FASB ASC. Authoritative guidance requires the Company to measure the cost of employee services received in exchange for an award of equity instruments, such as stock options or stock awards, based on the fair value of the award on the grant date. This cost must be recognized in the consolidated statements of income over the vesting period of the award. The Company issues restricted stock awards which generally vest over a four- or five-year period during which time the holder receives dividends and has full voting rights. Restricted stock is valued at the closing price of the Company’s stock on the date of an award. Derivatives and Hedging Activities In accordance with the Derivatives and Hedging topic of the FASB ASC, the Company recognizes derivatives as assets or liabilities on the consolidated balance sheets at their fair value. The treatment of changes in the fair value of derivatives depends on the character of the transaction. The Company enters into derivative contracts to add stability to interest income and to manage its exposure to changes in interest rates. On the date the Company enters into a derivative contract, the derivative instrument is designated as: (1) a hedge of the fair value of a recognized asset or liability or of an unrecognized firm commitment (a “fair value” hedge); (2) a hedge of the variability in expected future cash flows associated with an existing recognized asset or liability or a probable forecasted transaction (a “cash flow” hedge); or (3) held for other economic purposes (an “economic” hedge) and not formally designated as part of qualifying hedging relationships under authoritative guidance. In a fair value hedge, changes in the fair value of the hedging derivative are recognized in earnings and offset by recognizing changes in the fair value of the hedged item attributable to the risk being hedged. To the extent that the hedge is ineffective, the changes in fair value will not offset and the difference is reflected in earnings. In a cash flow hedge, the effective portion of the change in the fair value of the hedging derivative is recorded in accumulated other comprehensive income and is subsequently reclassified into earnings during the same period in which the hedged item affects earnings. The change in fair value of any ineffective portion of the hedging derivative is recognized immediately in earnings. When a cash flow hedge is discontinued, the net derivative gain or loss continues to be reported in accumulated other comprehensive income unless it is probable that the forecasted transactions will not occur by the end of the originally specified time period. The net derivative gain or loss from a discontinued cash flow hedge is reclassified into earnings during the originally specified time period in which the forecasted transactions were to occur. The Company formally documents the relationship between the hedging instruments and hedged items, as well as its risk management objective and strategy before initiating a hedge. To qualify for hedge accounting, the derivatives and related hedged items must be designated as a hedge. For hedging relationships in which effectiveness is measured, the correlations between the hedging instruments and hedged items are assessed at inception of the hedge and on an ongoing basis, which includes determining whether the hedge relationship is expected to be highly effective in offsetting changes in fair value or cash flows of hedged items. Derivatives used for other economic purposes are used as economic hedges in which the Company has not attempted to achieve the highly effective hedge accounting standard under authoritative guidance. The changes in fair value of these instruments are recognized immediately in earnings. Accounting Pronouncements During the year ended December 31, 2011, the following Accounting Standards Updates (“ASU”) were issued or became effective: In December 2011, the FASB issued ASU 2011-11, Disclosures about Offsetting Assets and Liabilities (Topic 210). ASU 2011-11 requires an entity to disclose information about offsetting and related arrangements to enable users of its financial statements to understand the effect of those arrangements on its financial position. ASU 2011-11 is effective for interim and annual periods beginning on or after January 1, 2013 and should be applied retrospectively for all comparative periods presented. The Company is evaluating the impact this ASU will have on its financial condition and results of operations. In September 2011, the FASB issued ASU 2011-08, Testing Goodwill for Impairment (Topic 350). ASU 2011-08 permits an entity to first assess qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount as a basis for determining whether it is necessary to perform the two-step goodwill impairment test. ASU 2011-08 is effective for interim and annual periods beginning after December 15, 2011. Early adoption is permitted. This ASU did not have any impact on the Company's financial condition or results of operations. In June 2011, the FASB issued ASU 2011-05, Presentation of Comprehensive Income (Topic 220). ASU 2011-05 attempts to improve the comparability, consistency, and transparency of financial reporting and to increase the prominence of items reported in other comprehensive income. The effective date of ASU 2011-05 will be the first interim or fiscal period beginning after December 15, 2011 and should be applied retrospectively. Early adoption is permitted. In December 2011, the FASB issued ASU 2011-11, Deferral of the Effective Date for Amendments to the Presentation of Reclassifications of Items Out of Accumulated Other Comprehensive Income in Accounting Standards Update No. 2011-05. ASU 2011-11 deferred the effective date for certain amendments related to the presentation of reclassification of items out of accumulated other comprehensive income. The Company adopted the remaining applicable amendments in ASU 2011-05 during the current period and the adoption of this ASU had no impact on the Company's financial condition or results of operations. In May 2011, the FASB issued ASU 2011-04, Amendments to Achieve Common Fair Value Measurement and Disclosure Requirements in U.S. Generally Accepted Accounting Principles (“GAAP”) and International Financial Reporting Standards (“IFRS”) (Topic 820). ASU 2011-04 developed common requirements between GAAP and IFRS for measuring fair value and for disclosing information about fair value measurements. The effective date of ASU 2011-04 will be during interim or annual period beginning after December 15, 2011 and should be applied prospectively to transactions or modifications of existing transactions that occur on or after the effective date. Early adoption is not permitted. The Company is evaluating the impact this ASU will have on its financial condition and results of operations. In April 2011, the FASB issued Accounting Standards Update ("ASU") 2011-03, Reconsideration of Effective Control for Repurchase Agreements (Topic 860). ASU 2011-03 attempts to improve the accounting for repurchase agreements and other agreements that both entitle and obligate a transferor to repurchase or redeem financial assets before maturity. The effective date of ASU 2011-03 will be the first interim or annual period beginning after December 15, 2011 and should be applied prospectively to transactions or modifications of existing transactions that occur on or after the effective date. Early adoption is not permitted. The Company is evaluating the impact this ASU will have on its financial condition and results of operations. In April 2011, the Financial Accounting Standards Board issued ASU 2011-02, A Creditor's Determination of Whether a Restructuring is a Troubled Debt Restructuring (Topic 310). ASU 2011-02 clarifies the criteria for a restructuring to be classified as a Troubled Debt Restructuring ("TDR"). The Company adopted this ASU during the current period as well as the related disclosure requirements which were included in ASU 2010-20, Disclosures about the Credit Quality of Financing Receivables and the Allowance for Credit Losses (Topic 310). Adoption of this ASU had no impact on the Company's financial condition or results of operations. See Note 5 for expanded disclosure requirements related to TDR.

Summary of Significant Accounting Policies

Organization

Columbia Banking System, Inc. (the “Corporation”) is the holding company for Columbia State Bank (the “Bank”). The Bank provides a full range of financial services through 102 branch locations, including 77 in the State of Washington and 25 in Oregon. Because the Bank comprises substantially all of the business of the Corporation, references to the “Company” mean the Corporation and the Bank together. The Corporation is approved as a bank holding company pursuant to the Gramm-Leach-Bliley Act of 1999.

The Company’s accounting and reporting policies conform to accounting principles generally accepted in the United States of America (“GAAP”) and practices in the financial services industry. To prepare the financial statements in conformity with GAAP, management must make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements, and income and expenses during the reporting period. Circumstances and events that differ significantly from those underlying our estimates and assumptions could cause actual financial results to differ from our estimates. The most significant estimates included in the financial statements relate to the allowance for loan and lease losses, business combinations, acquired impaired loans, Federal Deposit Insurance Corporation loss sharing asset and goodwill impairment.

The Company has applied its accounting policies and estimation methods consistently in all periods presented in these financial statements (to the periods in which they applied), except for certain estimates related to the measurement of expected future cash flows on acquired impaired loans. For those certain estimates, in 2011 the Company began utilizing actual historical loan data rather than industry data, which had been utilized in 2010. The results of operations reflect any adjustments, all of which are of a normal recurring nature, and which, in the opinion of management, are necessary for a fair presentation of the results of the periods presented.

Consolidation

The consolidated financial statements of the Company include the accounts of the Corporation and the Bank. Intercompany balances and transactions have been eliminated in consolidation.

Cash and cash equivalents

Cash and cash equivalents include cash and due from banks, and interest bearing balances due from correspondent banks and the Federal Reserve Bank. Cash and cash equivalents have a maturity of 90 days or less at the time of purchase.

Securities

Securities are classified based on management’s intention on the date of purchase. All securities are classified as available for sale and are presented at fair value. Unrealized gains or losses on securities available for sale are excluded from net income but are included as separate components of other comprehensive income, net of taxes. Purchase premiums or discounts on securities available for sale are amortized or accreted into income using the interest method over the terms of the individual securities. The Company performs a quarterly assessment to determine whether a decline in fair value below amortized cost is other-than-temporary. Amortized cost includes adjustments made to the cost of an investment for accretion, amortization, collection of cash and previous other-than temporary impairment recognized in earnings. Other-than-temporary impairment exists when it is probable that the Company will be unable to recover the entire amortized cost basis of the security. If the decline in fair value is judged to be other than temporary, the security is written down to fair value which becomes the new cost basis and an impairment loss is recognized.

In performing the quarterly assessment for debt securities, management considers whether or not the Company expects to recover the entire amortized cost basis of the security. In addition, management must determine its position with respect to its intent to sell the security and whether it is more likely than not that it will not have to sell the security before recovery of its cost basis. The total amount recognized in earnings when there are credit losses associated with an impaired debt security and management asserts that it does not have the intent to sell the security and it is more likely than not that it will not have to sell the security before recovery of its cost basis is separated into (a) the amount representing a credit loss and (b) the amount related to non-credit factors. The amount of impairment related to credit losses is recognized in earnings. The credit loss component of other-than-temporary impairment, representing an increase in credit risk, is determined by the Company using its best estimate of the present value of cash flows expected to be collected from the debt security. The amount of impairment related to non-credit factors is recognized in other comprehensive income. The previous cost basis less impairment recognized in earnings becomes the new cost basis of the security and is not adjusted for subsequent recoveries in fair value. However, the difference between the new amortized cost basis and the cash flows expected to be collected is accreted as interest income. The total other-than-temporary impairment is presented in the consolidated statements of income with a reduction for the amount of other-than-temporary impairment that is recognized in other comprehensive income, if any.

Realized gains or losses on sales of securities available for sale are recorded using the specific identification method.

Federal Home Loan Bank Stock

The Company’s investment in Federal Home Loan Bank (“FHLB”) stock is carried at par value because the shares can only be redeemed with the FHLB at par. The Company is required to maintain a minimum level of investment in FHLB stock based on specific percentages of its outstanding mortgages and FHLB advances. Stock redemptions are at the discretion of the FHLB or of the Company, upon five years’ prior notice for FHLB Class B stock or six months notice for FHLB Class A stock to the FHLB. FHLB stock is carried at cost and is subject to recoverability testing per the Financial Services—Depository and Lending topic of the FASB Accounting Standards Codification (“ASC”).

Loans

Loans are generally carried at the unpaid principal balance, net of premiums, unearned discounts and net deferred loan fees. Net deferred loan fees include deferred unamortized fees less direct incremental loan origination costs. Net deferred loan fees, premiums and unearned discounts on loans are recognized in interest income using either the interest method or straight-line method over the terms of the loans, adjusted for actual prepayments. Interest income is accrued as earned. Fees related to lending activities other than the origination or purchase of loans are recognized as noninterest income during the period the related services are performed.

Nonaccrual loans—Loans are placed on nonaccrual status when a loan becomes contractually past due 90 days with respect to interest or principal unless the loan is both well secured and in the process of collection, or if full collection of interest or principal becomes uncertain. When a loan is placed on nonaccrual status, any accrued and unpaid interest receivable is reversed and the recognition of net deferred loan fees, premiums and unearned discounts ceases. Thereafter, interest collected on the loan is accounted for on the cash collection or cost recovery method until qualifying for return to accrual status. Generally, a loan may be returned to accrual status when the delinquent principal and interest are brought current in accordance with the terms of the loan agreement and future payments are reasonably assured.

Impaired loans—Loans are considered impaired when based on current information and events, it is probable that the Company will be unable to collect all amounts due according to the contractual terms of the loan agreement or when a loan has been modified in a troubled debt restructuring. The assessment for impairment occurs when and while such loans are designated as classified per the Company’s internal risk rating system or when and while such loans are on nonaccrual. All nonaccrual loans greater than $250,000 are considered impaired and analyzed individually on a quarterly basis. Classified loans with an outstanding balance greater than $250,000 are evaluated for potential impairment on a quarterly basis.

When a loan with unique risk characteristics has been identified as being impaired, the amount of impairment will be measured by the Company using discounted cash flows, except when it is determined that the primary (remaining) source of repayment for the loan is the operation or liquidation of the underlying collateral. In these cases, the current fair value of the collateral, reduced by costs to sell, will be used in place of discounted cash flows. As a final alternative, the observable market price of the debt may be used to assess impairment. Predominantly, the Company uses the fair value of collateral approach based upon a reliable valuation.

When the measurement of the impaired loan is less than the recorded amount of the loan, an impairment is recognized by recording a charge-off to the allowance for loan and lease losses or by designating a specific reserve. The Company’s policy is to record cash receipts received on impaired loans first as reductions to principal and then to interest income.

Restructured Loans—A loan is classified as a troubled debt restructuring when a borrower is experiencing financial difficulties that lead to a restructuring of the loan, and the Company grants concessions to the borrower in the restructuring that it would not otherwise consider. These concessions may include interest rate reductions, principal forgiveness, extension of maturity date and other actions intended to minimize potential losses. Generally, a nonaccrual loan that is restructured remains on nonaccrual status for a period of six months to demonstrate that the borrower can meet the restructured terms. If the borrower's performance under the new terms is not reasonably assured, the loan remains classified as a nonaccrual loan.

Acquired Impaired Loans—Loans acquired with evidence of credit deterioration since origination for which it is probable that all contractually required payments will not be collected are accounted for under Accounting Standards Codification (“ASC”) 310-30, Loans and Debt Securities Acquired with Deteriorated Credit Quality, formerly SOP 03-3 Accounting for Certain Loans or Debt Securities Acquired in a Transfer. In addition, because of the significant discounts associated with certain of the acquired loan portfolios, the Company elected to account for those certain acquired loans under ASC 310-30.

In situations where such loans have similar risk characteristics, loans are aggregated into pools to estimate cash flows. A pool is accounted for as a single asset with a single interest rate, cumulative loss rate and cash flow expectation. Expected cash flows at the acquisition date in excess of the fair value of loans are considered to be accretable yield, which is recognized as interest income over the life of the loan pool using a level yield method if the timing and amount of the future cash flows of the pool is reasonably estimable. Subsequent to the acquisition date, any increases in cash flow over those expected at purchase date in excess of fair value are recorded as interest income prospectively. Any subsequent decreases in cash flow over those expected at purchase date due to credit deterioration are recognized by recording an allowance for losses on covered loans. Any disposals of loans, including sales of loans, payments in full or foreclosures result in the removal of the loan from the loan pool at the carrying amount.

Covered Loans—The term covered loans refers to acquired loans that are covered under a loss-sharing agreement with the FDIC. Substantially all covered loans are accounted for under ASC 310-30. See Acquired Impaired Loans for further discussion.

Unfunded loan commitments—Unfunded commitments are generally related to providing credit facilities to clients of the Bank and are not actively traded financial instruments. These unfunded commitments are disclosed as financial instruments with off-balance sheet risk in Note 17 in the Notes to Consolidated Financial Statements.

Allowance for Loan and Lease Losses

The Company accounts for the credit risk associated with lending activities through its allowance for loan and lease losses and provision for loan and lease losses. The provision is the expense recognized in the consolidated statements of income to adjust the allowance to the levels deemed appropriate by management, as determined through application of the Company’s allowance methodology procedures. The provision for loan and lease losses reflects management’s judgment of the adequacy of the allowance for loan and lease losses. Loan and lease losses are charged against the allowance when management believes the collectability of a loan balance is unlikely. Subsequent recoveries, if any, are credited to the allowance.

The allowance for loan and lease losses is evaluated on a regular basis by management and is based upon management’s periodic review of the collectability of the loans in light of historical experience, the nature and volume of the loan portfolio, adverse situations that may affect the borrower’s ability to repay, estimated value of any underlying collateral and prevailing economic conditions. This evaluation is inherently subjective as it requires estimates that are susceptible to significant revision as more information becomes available.

The allowance consists of general, specific, and unallocated components. The general component covers loans not specifically measured for impairment and is based on historical loss experience adjusted for qualitative factors. The specific component relates to loans that are impaired. For impaired loans an allowance is established when the discounted cash flows (or collateral value or observable market price) of the impaired loan is lower than the carrying value of that loan. The unallocated allowance provides for other credit losses inherent in the Company’s loan portfolio that may not have been contemplated in the general and specific components of the allowance. This unallocated amount generally comprises less than 5% of the allowance. The unallocated amount is reviewed periodically based on trends in credit losses, the results of credit reviews and overall economic trends.

Allowance for Unfunded Commitments and Letters of Credit

The allowance for unfunded commitments is maintained at a level believed by management to be sufficient to absorb estimated probable losses related to these unfunded credit facilities. The determination of the adequacy of the allowance is based on periodic evaluations of the unfunded credit facilities including an assessment of the probability of commitment usage, credit risk factors for loans outstanding to these same customers, and the terms and expiration dates of the unfunded credit facilities. The allowance for unfunded commitments is included in other liabilities on the consolidated balance sheets, with changes to the balance charged against noninterest expense.

Allowance for Loan Losses on Covered Loans

The Company updates its cash flow projections for covered loans accounted for under ASC 310-30 on a quarterly basis. Assumptions utilized in this process include projections related to probability of default, loss severity, prepayment and recovery lag. Projections related to probability of default and prepayment are calculated utilizing a loan migration analysis. The loan migration analysis is a matrix of probability that specifies the probability of a loan pool transitioning into a particular delinquency state given its delinquency state at the re-measurement date. Loss severity factors are based upon actual charge-off data within the loan pools and recovery lags are based upon the collateral within the loan pools.

Any decreases in expected cash flows after the acquisition date and subsequent measurement periods are recognized by recording a provision for loan losses. See Acquired Impaired Loans for further discussion.

Premises and Equipment

Land, buildings, leasehold improvements and equipment are stated at cost less accumulated depreciation and amortization. Buildings and equipment are depreciated over their estimated useful lives using the straight-line method. Leasehold improvements are amortized over the shorter of their useful lives or lease terms. Gains or losses on dispositions are reflected in current operations. Expenditures for improvements and major renewals are capitalized, and ordinary maintenance, repairs and small purchases are charged to operating expenses.

Software

Capitalized software is stated at cost, less accumulated amortization. Amortization is computed on a straight-line basis and charged to expense over the estimated useful life of the software which is generally three years. Capitalized software is included in Premises and equipment, net in the Consolidated Balance Sheets.

Other Real Estate Owned

Other real estate owned (“OREO”) is composed of real estate acquired in satisfaction of loans. Properties acquired by foreclosure or deed in lieu of foreclosure are transferred to OREO and are recorded at fair value less estimated costs to sell, at the date of transfer of the property. If the carrying value exceeds the fair value at the time of the transfer, the difference is charged to the allowance for loan and lease losses. The fair value of the OREO property is based upon current appraisal. Losses that result from the ongoing periodic valuation of these properties are charged to the net cost of operation of OREO in the period in which they are identified. Improvements to the OREO are capitalized and holding costs are charged to the net cost of operation of OREO as incurred.

Covered OREO—Covered OREO includes acquired OREO that is covered under a loss-sharing agreement with the FDIC. These assets were recorded at their fair value on acquisition date. Covered OREO is reported in Other real estate owned in the Consolidated Balance Sheets. Covered OREO is reported exclusive of expected reimbursement cash flows from the FDIC. Upon transferring covered loan collateral to covered OREO status, valuation adjustments arising from acquisition accounting on the related loan are also transferred to covered OREO. Valuation adjustments arising from acquisition accounting on covered OREO result in a reduction of the covered OREO carrying amount and a corresponding increase in the expected FDIC reimbursement, with the estimated net loss to the Company, if any, charged against earnings.

FDIC Loss-sharing Asset

The acquisition date fair value of the reimbursement the Company expected to receive from the FDIC under loss-sharing agreements was recorded in the FDIC loss-sharing asset on the Consolidated Balance Sheet. Subsequent to initial recognition, the FDIC loss-sharing asset is reviewed quarterly and adjusted for any changes in expected cash flows. These adjustments are measured on the same basis as the related covered assets. Any decrease in expected cash flows due to an increase in expected credit losses will increase the FDIC loss-sharing asset and any increase in expected future cash flows due to a decrease in expected credit losses will decrease the FDIC loss-sharing asset. Increases and decreases to the FDIC loss-sharing asset are recorded as adjustments to noninterest income.

Goodwill and Intangibles

Net assets of companies acquired in purchase transactions are recorded at fair value at the date of acquisition. Identified intangibles are amortized on an accelerated basis over the period benefited. Goodwill is not amortized but is reviewed for potential impairment during the third quarter on an annual basis or, more frequently, if events or circumstances indicate a potential impairment, at the reporting unit level. A reporting unit is an operating segment or one level below an operating segment for which discrete financial information is available and regularly reviewed by management. If the fair value of the reporting unit, including goodwill, is determined to be less than the carrying amount of the reporting unit, a further test is required to measure the amount of impairment. If an impairment loss exists, the carrying amount of goodwill is adjusted to a new cost basis. Subsequent reversal of a previously recognized goodwill impairment loss is prohibited.

Intangible assets are evaluated for impairment if events and circumstances indicate a possible impairment. Such evaluation of other intangible assets is based on undiscounted cash flow projections. At December 31, 2011, intangible assets included on the consolidated balance sheets consist of a core deposit intangible amortized using an accelerated method with an original estimated life of approximately 10 years.

Income Taxes

The provision for income taxes includes current and deferred income tax expense on net income adjusted for permanent and temporary differences such as interest income on state and municipal securities and affordable housing credits. Deferred tax assets and liabilities are recognized for the expected future tax consequences of existing temporary differences between the financial reporting and tax reporting basis of assets and liabilities using enacted tax laws and rates. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. On a quarterly basis, management evaluates deferred tax assets to determine if these tax benefits are expected to be realized in future periods. This determination is based on facts and circumstances, including the Company’s current and future tax outlook. To the extent a deferred tax asset is no longer considered “more likely than not” to be realized, a valuation allowance is established.

Advertising

Advertising costs are generally expensed as incurred.

Earnings per Common Share

The Company calculates earnings per common share (“EPS”) using the two-class method in accordance with the Earnings per Share topic of the FASB ASC. The two-class method requires the Company to present EPS as if all of the earnings for the period are distributed to common shareholders and any participating securities, regardless of whether any actual dividends or distributions are made. Under authoritative guidance, all outstanding unvested share-based payment awards that contain rights to nonforfeitable dividends are considered participating securities. The Company grants restricted shares under a share-based compensation plan that qualifies as participating securities. Restricted shares issued under the Company’s share-based compensation plan are entitled to dividends at the same rate as common stock.

Basic EPS are computed by dividing distributed and undistributed earnings available to common shareholders by the weighted average number of common shares outstanding for the period. Distributed and undistributed earnings available to common shareholders represent net income reduced by preferred stock dividends and distributed and undistributed earnings available to participating securities. Common shares outstanding include common stock and vested restricted stock awards. Diluted EPS reflect the assumed conversion of all potential dilutive securities.

Share-Based Payment

The Company accounts for stock options and stock awards in accordance with the Compensation—Stock Compensation topic of the FASB ASC. Authoritative guidance requires the Company to measure the cost of employee services received in exchange for an award of equity instruments, such as stock options or stock awards, based on the fair value of the award on the grant date. This cost must be recognized in the consolidated statements of income over the vesting period of the award.

The Company issues restricted stock awards which generally vest over a four- or five-year period during which time the holder receives dividends and has full voting rights. Restricted stock is valued at the closing price of the Company’s stock on the date of an award.

Derivatives and Hedging Activities

In accordance with the Derivatives and Hedging topic of the FASB ASC, the Company recognizes derivatives as assets or liabilities on the consolidated balance sheets at their fair value. The treatment of changes in the fair value of derivatives depends on the character of the transaction.

The Company enters into derivative contracts to add stability to interest income and to manage its exposure to changes in interest rates. On the date the Company enters into a derivative contract, the derivative instrument is designated as: (1) a hedge of the fair value of a recognized asset or liability or of an unrecognized firm commitment (a “fair value” hedge); (2) a hedge of the variability in expected future cash flows associated with an existing recognized asset or liability or a probable forecasted transaction (a “cash flow” hedge); or (3) held for other economic purposes (an “economic” hedge) and not formally designated as part of qualifying hedging relationships under authoritative guidance.

In a fair value hedge, changes in the fair value of the hedging derivative are recognized in earnings and offset by recognizing changes in the fair value of the hedged item attributable to the risk being hedged. To the extent that the hedge is ineffective, the changes in fair value will not offset and the difference is reflected in earnings.

In a cash flow hedge, the effective portion of the change in the fair value of the hedging derivative is recorded in accumulated other comprehensive income and is subsequently reclassified into earnings during the same period in which the hedged item affects earnings. The change in fair value of any ineffective portion of the hedging derivative is recognized immediately in earnings. When a cash flow hedge is discontinued, the net derivative gain or loss continues to be reported in accumulated other comprehensive income unless it is probable that the forecasted transactions will not occur by the end of the originally specified time period. The net derivative gain or loss from a discontinued cash flow hedge is reclassified into earnings during the originally specified time period in which the forecasted transactions were to occur.

The Company formally documents the relationship between the hedging instruments and hedged items, as well as its risk management objective and strategy before initiating a hedge. To qualify for hedge accounting, the derivatives and related hedged items must be designated as a hedge. For hedging relationships in which effectiveness is measured, the correlations between the hedging instruments and hedged items are assessed at inception of the hedge and on an ongoing basis, which includes determining whether the hedge relationship is expected to be highly effective in offsetting changes in fair value or cash flows of hedged items.

Derivatives used for other economic purposes are used as economic hedges in which the Company has not attempted to achieve the highly effective hedge accounting standard under authoritative guidance. The changes in fair value of these instruments are recognized immediately in earnings.

Accounting Pronouncements

During the year ended December 31, 2011, the following Accounting Standards Updates (“ASU”) were issued or became effective:

In December 2011, the FASB issued ASU 2011-11, Disclosures about Offsetting Assets and Liabilities (Topic 210). ASU 2011-11 requires an entity to disclose information about offsetting and related arrangements to enable users of its financial statements to understand the effect of those arrangements on its financial position. ASU 2011-11 is effective for interim and annual periods beginning on or after January 1, 2013 and should be applied retrospectively for all comparative periods presented. The Company is evaluating the impact this ASU will have on its financial condition and results of operations.

In September 2011, the FASB issued ASU 2011-08, Testing Goodwill for Impairment (Topic 350). ASU 2011-08 permits an entity to first assess qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount as a basis for determining whether it is necessary to perform the two-step goodwill impairment test. ASU 2011-08 is effective for interim and annual periods beginning after December 15, 2011. Early adoption is permitted. This ASU did not have any impact on the Company's financial condition or results of operations.

In June 2011, the FASB issued ASU 2011-05, Presentation of Comprehensive Income (Topic 220). ASU 2011-05 attempts to improve the comparability, consistency, and transparency of financial reporting and to increase the prominence of items reported in other comprehensive income. The effective date of ASU 2011-05 will be the first interim or fiscal period beginning after December 15, 2011 and should be applied retrospectively. Early adoption is permitted. In December 2011, the FASB issued ASU 2011-11, Deferral of the Effective Date for Amendments to the Presentation of Reclassifications of Items Out of Accumulated Other Comprehensive Income in Accounting Standards Update No. 2011-05. ASU 2011-11 deferred the effective date for certain amendments related to the presentation of reclassification of items out of accumulated other comprehensive income. The Company adopted the remaining applicable amendments in ASU 2011-05 during the current period and the adoption of this ASU had no impact on the Company's financial condition or results of operations.

In May 2011, the FASB issued ASU 2011-04, Amendments to Achieve Common Fair Value Measurement and Disclosure Requirements in U.S. Generally Accepted Accounting Principles (“GAAP”) and International Financial Reporting Standards (“IFRS”) (Topic 820). ASU 2011-04 developed common requirements between GAAP and IFRS for measuring fair value and for disclosing information about fair value measurements. The effective date of ASU 2011-04 will be during interim or annual period beginning after December 15, 2011 and should be applied prospectively to transactions or modifications of existing transactions that occur on or after the effective date. Early adoption is not permitted. The Company is evaluating the impact this ASU will have on its financial condition and results of operations.

In April 2011, the FASB issued Accounting Standards Update ("ASU") 2011-03, Reconsideration of Effective Control for Repurchase Agreements (Topic 860). ASU 2011-03 attempts to improve the accounting for repurchase agreements and other agreements that both entitle and obligate a transferor to repurchase or redeem financial assets before maturity. The effective date of ASU 2011-03 will be the first interim or annual period beginning after December 15, 2011 and should be applied prospectively to transactions or modifications of existing transactions that occur on or after the effective date. Early adoption is not permitted. The Company is evaluating the impact this ASU will have on its financial condition and results of operations.

In April 2011, the Financial Accounting Standards Board issued ASU 2011-02, A Creditor's Determination of Whether a Restructuring is a Troubled Debt Restructuring (Topic 310). ASU 2011-02 clarifies the criteria for a restructuring to be classified as a Troubled Debt Restructuring ("TDR"). The Company adopted this ASU during the current period as well as the related disclosure requirements which were included in ASU 2010-20, Disclosures about the Credit Quality of Financing Receivables and the Allowance for Credit Losses (Topic 310). Adoption of this ASU had no impact on the Company's financial condition or results of operations. See Note 5 for expanded disclosure requirements related to TDR.