Summary Of Significant Accounting Policies (Policy)	12 Months Ended
Dec. 31, 2011
Summary Of Significant Accounting Policies [Abstract]
Nature Of Operations	Nature of Operations Commerce Bancshares, Inc. and its subsidiaries (the Company) conducts its principal activities from approximately 360 locations throughout Missouri, Illinois, Kansas, Oklahoma and Colorado. Principal activities include retail and commercial banking, investment management, securities brokerage, mortgage banking, credit related insurance and private equity investment activities.
Basis Of Presentation	Basis of Presentation The Company follows accounting principles generally accepted in the United States of America (GAAP) and reporting practices applicable to the banking industry. The preparation of financial statements under GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and notes. These estimates are based on information available to management at the time the estimates are made. While the consolidated financial statements reflect management's best estimates and judgments, actual results could differ from those estimates. The consolidated financial statements include the accounts of the Company and its majority-owned subsidiaries (after elimination of all material intercompany balances and transactions). Certain amounts for prior years have been reclassified to conform to the current year presentation. Such reclassifications had no effect on net income or total assets.
Cash And Cash Equivalent	Cash and Cash Equivalents In the accompanying consolidated statements of cash flows, cash and cash equivalents include "Cash and due from banks", "Short-term federal funds sold and securities purchased under agreements to resell", and "Interest earning deposits with banks" as segregated in the accompanying consolidated balance sheets.
Loans And Related Earnings	Loans and Related Earnings Loans that management has the intent and ability to hold for the foreseeable future or until maturity or pay-off are reported at their outstanding principal balances, net of undisbursed loan proceeds, the allowance for loan losses, and any deferred fees and costs on originated loans. Origination fee income received on loans and amounts representing the estimated direct costs of origination are deferred and amortized to interest income over the life of the loan using the interest method. Prepayment premium or yield maintenance agreements are generally required on all term commercial loans with fixed rate intervals of three years or more. Interest on loans is accrued based upon the principal amount outstanding. Interest income is recognized primarily on the level yield method. Loan and commitment fees, net of costs, are deferred and recognized in income over the term of the loan or commitment as an adjustment of yield. Annual fees charged on credit card loans are capitalized to principal and amortized over 12 months to loan fees and sales in the accompanying consolidated income statements. Other credit card fees, such as cash advance fees and late payment fees, are recognized in income as an adjustment of yield when charged to the cardholder's account.
Non-Accrual Loans	Non-Accrual Loans Loans are placed on non-accrual status when management does not expect to collect payments consistent with acceptable and agreed upon terms of repayment. Business, construction real estate, business real estate, and personal real estate loans that are contractually 90 days past due as to principal and/or interest payments are generally placed on non-accrual, unless they are both well-secured and in the process of collection. Consumer, revolving home equity and credit card loans are exempt under regulatory rules from being classified as non-accrual. When a loan is placed on non-accrual status, any interest previously accrued but not collected is reversed against current income, and the loan is charged off to the extent uncollectible. Principal and interest payments received on non-accrual loans are generally applied to principal. Interest is included in income only after all previous loan charge-offs have been recovered and is recorded only as received. The loan is returned to accrual status only when the borrower has brought all past due principal and interest payments current and, in the opinion of management, the borrower has demonstrated the ability to make future payments of principal and interest as scheduled. A six month history of sustained payment performance is generally required before reinstatement of accrual status.
Restructured Loans	Restructured Loans A loan is accounted for as a troubled debt restructuring if the Company, for economic or legal reasons related to the borrowers' financial difficulties, grants a concession to the borrower that it would not otherwise consider. A troubled debt restructuring typically involves a modification of terms such as a reduction of the stated interest rate or face amount of the loan, a reduction of accrued interest, or an extension of the maturity date at a stated interest rate lower than the current market rate for a new loan with similar risk. The Company measures the impairment loss of a troubled debt restructuring based on the difference between the original loan's carrying amount and the present value of expected future cash flows discounted at the original, contractual rate of the loan. Business, business real estate, construction real estate and personal real estate loans whose terms have been modified in a troubled debt restructuring with impairment charges are generally placed on non-accrual status. Other loans identified as troubled debt restructurings were so designated because they were renewed at interest rates that were not deemed to represent current market rates for debt of similar risk. These loans are performing under their modified terms, and interest continues to be accrued and recognized in income. Troubled debt restructurings also include certain credit card loans which have been modified under various debt management and assistance programs.
Impaired Loans	Impaired Loans Loans are evaluated regularly by management for impairment. Included in impaired loans are all non-accrual loans, as well as loans whose terms have been modified in a troubled debt restructuring, as discussed above. Once a loan has been identified as impaired, impairment is measured based on either the present value of the expected future cash flows at the loan's initial effective interest rate or the fair value of the collateral if collateral dependent. Factors considered in determining impairment include delinquency status, cash flow analysis, credit analysis, and collateral value and availability.
Loans Held For Sale	Loans Held for Sale Loans held for sale include student loans and fixed rate residential mortgage loans. These loans are typically classified as held for sale upon origination based upon management's intent to sell all the production of these loans. They are carried at the lower of aggregate cost or fair value. Fair value is determined based on prevailing market prices for loans with similar characteristics, sale contract prices, or, for those portfolios for which management has concerns about contractual performance, discounted cash flow analyses. Declines in fair value below cost (and subsequent recoveries) are recognized in loan fees and sales. Deferred fees and costs related to these loans are not amortized but are recognized as part of the cost basis of the loan at the time it is sold. Gains or losses on sales are recognized upon delivery and included in loan fees and sales.
Allowance/Provision For Loan Losses	Allowance/Provision for Loan Losses The allowance for loan losses is maintained at a level believed to be appropriate by management to provide for probable loan losses inherent in the portfolio as of the balance sheet date, including losses on known or anticipated problem loans as well as for loans which are not currently known to require specific allowances. Management has established a process to determine the amount of the allowance for loan losses which assesses the risks and losses inherent in its portfolio. Business, construction real estate and business real estate loans are normally larger and more complex, and their collection rates are harder to predict. These loans are more likely to be collateral dependent and are allocated a larger reserve, due to their potential volatility. Personal real estate, credit card, consumer and revolving home equity loans are individually smaller and perform in a more homogenous manner, making loss estimates more predictable. Management's process provides an allowance consisting of a specific allowance component based on certain individually evaluated loans and a general component based on estimates of reserves needed for pools of loans. Loans subject to individual evaluation generally consist of business, construction real estate, business real estate and personal real estate loans on non-accrual status. These impaired loans are evaluated individually for the impairment of repayment potential and collateral adequacy, and in conjunction with current economic conditions and loss experience, allowances are estimated. Certain other impaired loans identified as troubled debt restructurings are collectively evaluated because they have similar risk characteristics. Loans which have not been identified as impaired are segregated by loan type and sub-type and are collectively evaluated. Reserves calculated for these loan pools are estimated using a consistent methodology that considers historical loan loss experience by loan type, delinquencies, current economic factors, loan risk ratings and industry concentrations. The Company's estimate of the allowance for loan losses and the corresponding provision for loan losses is based on various judgments and assumptions made by management. The amount of the allowance for loan losses is highly dependent on management's estimates affecting valuation, appraisal of collateral, evaluation of performance and status, and the amount and timing of future cash flows expected to be received on impaired loans. Factors that influence these judgments include past loan loss experience, current loan portfolio composition and characteristics, trends in portfolio risk ratings, levels of non-performing assets, prevailing regional and national economic conditions, and the Company's ongoing loan review process. The estimates, appraisals, evaluations, and cash flows utilized by management may be subject to frequent adjustments due to changing economic prospects of borrowers or properties. These estimates are reviewed periodically and adjustments, if necessary, are recorded in the provision for loan losses in the periods in which they become known. Loans, or portions of loans, are charged off to the extent deemed uncollectible. Loan charge-offs reduce the allowance for loan losses, and recoveries of loans previously charged off are added back to the allowance. Business, business real estate, construction real estate and personal real estate loans are generally charged down to estimated collectible balances when they are placed on non-accrual status. Consumer loans and related accrued interest are normally charged down to the fair value of related collateral (or are charged off in full if no collateral) once the loans are more than 120 days delinquent. Credit card loans are charged off against the allowance for loan losses when the receivable is more than 180 days past due. The interest and fee income previously capitalized but not collected on credit card charge-offs is reversed against interest income.
Operating, Direct Financing And Sales Type Leases	Operating, Direct Financing and Sales Type Leases The net investment in direct financing and sales type leases is included in loans on the Company's consolidated balance sheets, and consists of the present values of the sum of the future minimum lease payments and estimated residual value of the leased asset. Revenue consists of interest earned on the net investment and is recognized over the lease term as a constant percentage return thereon. The net investment in operating leases is included in other assets on the Company's consolidated balance sheets. It is carried at cost, less the amount depreciated to date. Depreciation is recognized, on the straight-line basis, over the lease term to the estimated residual value. Operating lease revenue consists of the contractual lease payments and is recognized over the lease term in other non-interest income. Estimated residual values are established at lease inception utilizing contract terms, past customer experience, and general market data and are reviewed and adjusted, if necessary, on an annual basis.
Investments In Debt And Equity Securities	Investments in Debt and Equity Securities The Company has classified the majority of its investment portfolio as available for sale. From time to time, the Company sells securities and utilizes the proceeds to reduce borrowings, fund loan growth, or modify its interest rate profile. Securities classified as available for sale are carried at fair value. Changes in fair value, excluding certain losses associated with other-than-temporary impairment (OTTI), are reported in other comprehensive income (loss), a component of stockholders' equity. Securities are periodically evaluated for OTTI in accordance with guidance provided in ASC 320-10-35. For securities with OTTI, the entire loss in fair value is required to be recognized in current earnings if the Company intends to sell the securities or believes it likely that it will be required to sell the security before the anticipated recovery. If neither condition is met, but the Company does not expect to recover the amortized cost basis, the Company determines whether a credit loss has occurred, and the loss is then recognized in current earnings. The noncredit-related portion of the overall loss is reported in other comprehensive income (loss). Mortgage and asset-backed securities whose credit ratings are below AA at their purchase date are evaluated for OTTI under ASC 325-40-35, which requires evaluations for OTTI at purchase date and in subsequent periods. Gains and losses realized upon sales of securities are calculated using the specific identification method and are included in Investment securities gains (losses), net in the consolidated statements of income. Premiums and discounts are amortized to interest income over the estimated lives of the securities. Prepayment experience is continually evaluated to determine the appropriate estimate of the future rate of prepayment. When a change in a bond's estimated remaining life is necessary, a corresponding adjustment is made in the related amortization of premium or discount accretion. Non-marketable securities include certain private equity investments, consisting of both debt and equity instruments. These securities are carried at fair value in accordance with ASC 946-10-15, with changes in fair value reported in current earnings. In the absence of readily ascertainable market values, fair value is estimated using internally developed models. Changes in fair value and gains and losses from sales are included in Investment securities gains (losses), net. Other non-marketable securities acquired for debt and regulatory purposes are accounted for at cost. Trading account securities, which are bought and held principally for the purpose of resale in the near term, are carried at fair value. Gains and losses, both realized and unrealized, are recorded in non-interest income. Purchases and sales of securities are recognized on a trade date basis. A receivable or payable is recognized for pending transaction settlements.
Securities Purchased Under Agreements To Resell And Securities Sold Under Agreements To Repurchase	Securities Purchased under Agreements to Resell and Securities Sold under Agreements to Repurchase The Company periodically enters into investments of securities under agreements to resell with large financial institutions. These agreements are accounted for as collateralized financing transactions. Securities pledged by the counterparties to secure these agreements are delivered to a third party custodian. Collateral is valued daily, and the Company may require counterparties to deposit additional collateral, or the Company may return collateral pledged when appropriate to maintain full collateralization for these transactions. At December 31, 2011, the Company had entered into $850.0 million of long-term agreements to resell and had accepted securities valued at $894.4 million as collateral. Securities sold under agreements to repurchase are offered to cash management customers as an automated, collateralized investment account and totaled $702.8 million at December 31, 2011. Securities sold are also used by the Bank to obtain additional borrowed funds at favorable rates, and at December 31, 2011, such securities sold totaled $400.0 million of long-term structured repurchase agreements. As of December 31, 2011, the Company had pledged $2.0 billion of available for sale securities as collateral for repurchase agreements.
Land, Buildings And Equipment	Land, Buildings and Equipment Land is stated at cost, and buildings and equipment are stated at cost, including capitalized interest when appropriate, less accumulated depreciation. Depreciation is computed using straight-line and accelerated methods. The Company generally assigns depreciable lives of 30 years for buildings, 10 years for building improvements, and 3 to 8 years for equipment. Leasehold improvements are amortized over the shorter of their estimated useful lives or remaining lease terms. Maintenance and repairs are charged to non-interest expense as incurred.
Foreclosed Assets	Foreclosed Assets Foreclosed assets consist of property that has been repossessed and is comprised of commercial and residential real estate and other non-real estate property, including auto and recreational and marine vehicles. The assets are initially recorded at fair value less estimated selling costs, with any valuation adjustments charged to the allowance for loan losses. Fair values are estimated primarily based on appraisals when available or quoted market prices of liquid assets. After their initial recognition, foreclosed assets are valued at the lower of the amount recorded at acquisition date or the current fair value less estimated costs to sell. Any resulting valuation adjustments, in addition to gains and losses realized on sales and net operating expenses, are recorded in other non-interest expense.
Derivatives	Derivatives The Company is exposed to market risk, including changes in interest rates and currency exchange rates. To manage the volatility relating to these exposures, the Company's risk management policies permit its use of derivative products. The Company manages potential credit exposure through established credit approvals, risk control limits and other monitoring procedures. The Company uses derivatives on a limited basis mainly to stabilize interest rate margins and hedge against interest rate movements. The Company more often manages normal asset and liability positions by altering the products it offers and by selling portions of specific loan or investment portfolios as necessary. Derivative accounting guidance requires that all derivative financial instruments be recorded on the balance sheet at fair value, with the adjustment to fair value recorded in current earnings. Derivatives that are part of a qualifying hedging relationship under ASC 815-20-25 can be designated, based on the exposure being hedged, as fair value or cash flow hedges. Under the fair value hedging model, gains or losses attributable to the change in fair value of the derivative, as well as gains and losses attributable to the change in fair value of the hedged item, are recognized in current earnings. Under the cash flow hedging model, the effective portion of the gain or loss related to the derivative is recognized as a component of other comprehensive income. The ineffective portion is recognized in current earnings. The Company formally documents all hedging relationships between hedging instruments and the hedged item, as well as its risk management objective. At December 31, 2011, the Company had three interest rate swaps designated as fair value hedges. The Company performs quarterly assessments, using the regression method, to determine whether the hedging relationship has been highly effective in offsetting changes in fair values. Derivative contracts are also offered to customers to assist in hedging their risks of adverse changes in interest rates and foreign exchange rates. The Company serves as an intermediary between its customers and the markets. Each contract between the Company and its customers is offset by a contract between the Company and various counterparties. These contracts do not qualify for hedge accounting. They are carried at fair value, with changes in fair value recorded in other non-interest income. As each customer contract is paired with an offsetting contract, the impact to net income is minimized. The Company enters into interest rate lock commitments on mortgage loans, which are commitments to originate loans whereby the interest rate on the loan is determined prior to funding. The Company also has corresponding forward sales contracts related to these interest rate lock commitments. Both the mortgage loan commitments and the related sales contracts are accounted for as derivatives and carried at fair value, with changes in fair value recorded in loan fees and sales. Fair values are based upon quoted prices, and fair value measurements of mortgage loan commitments include the value of loan servicing rights.
Income Taxes	Income Taxes Amounts provided for income tax expense are based on income reported for financial statement purposes and do not necessarily represent amounts currently payable under tax laws. Deferred income taxes are provided for temporary differences between the financial reporting bases and income tax bases of the Company's assets and liabilities, net operating losses, and tax credit carryforwards. Deferred tax assets and liabilities are measured using the enacted tax rates that are expected to apply to taxable income when such assets and liabilities are anticipated to be settled or realized. The effect on deferred tax assets and liabilities of a change in tax rates is recognized as tax expense or benefit in the period that includes the enactment date of the change. In determining the amount of deferred tax assets to recognize in the financial statements, the Company evaluates the likelihood of realizing such benefits in future periods. A valuation allowance is established if it is more likely than not that all or some portion of the deferred tax asset will not be realized. The Company recognizes interest and penalties related to income taxes within income tax expense in the consolidated statements of income. The Company and its eligible subsidiaries file a consolidated federal income tax return. State and local income tax returns are filed on a combined, consolidated or separate return basis based upon each jurisdiction's laws and regulations.
Intangible Assets	Intangible Assets Goodwill and intangible assets that have indefinite useful lives are not amortized, but are tested annually for impairment. Intangible assets that have finite useful lives, such as core deposit intangibles and mortgage servicing rights, are amortized over their estimated useful lives. Core deposit intangibles are amortized over periods of 8 to 14 years, representing their estimated lives, using accelerated methods. Mortgage servicing rights are amortized in proportion to and over the period of estimated net servicing income, considering appropriate prepayment assumptions. When facts and circumstances indicate potential impairment of amortizable intangible assets, the Company evaluates the recoverability of the asset carrying value, using estimates of undiscounted future cash flows over the remaining asset life. Any impairment loss is measured by the excess of carrying value over fair value. Goodwill impairment tests are performed on an annual basis or when events or circumstances dictate. In these tests, the fair value of each reporting unit, or segment, is compared to the carrying amount of that reporting unit in order to determine if impairment is indicated. If so, the implied fair value of the reporting unit's goodwill is compared to its carrying amount, and the impairment loss is measured by the excess of the carrying value over fair value. There has been no impairment resulting from goodwill impairment tests. However, adverse changes in the economic environment, operations of the reporting unit, or other factors could result in a decline in the implied fair value.
Pension Plan	Pension Plan The Company's pension plan is described in Note 9, Employee Benefit Plans. The funded status of the plan is recognized as an asset or liability in the balance sheet, and changes in that funded status are recognized in the year in which the changes occur through other comprehensive income. Plan assets and benefit obligations are measured as of fiscal year end. The measurement of the projected benefit obligation and pension expense involve actuarial valuation methods and the use of various actuarial and economic assumptions. The Company monitors the assumptions and updates them periodically. Due to the long-term nature of the pension plan obligation, actual results may differ significantly from estimations. Such differences are adjusted over time as the assumptions are replaced by facts and values are recalculated.
Stock-Based Compensation	Stock-Based Compensation The Company's stock-based employee compensation plan is described in Note 10, Stock-Based Compensation and Directors Stock Purchase Plan. In accordance with the requirements of ASC 718-10-30-3 and 35-2, the Company measures the cost of stock-based compensation based on the grant-date fair value of the award, recognizing the cost over the requisite service period. The fair value of an award is estimated using the Black-Scholes option-pricing model. The expense recognized is based on an estimation of the number of awards for which the requisite service is expected to be rendered and is included in salaries and employee benefits in the accompanying consolidated statements of income.
Treasury Stock	Treasury Stock Purchases of the Company's common stock are recorded at cost. Upon re-issuance for acquisitions, exercises of stock-based awards or other corporate purposes, treasury stock is reduced based upon the average cost basis of shares held.
Income Per Share	Income per Share Basic income per share is computed using the weighted average number of common shares outstanding during each year. Diluted income per share includes the effect of all dilutive potential common shares (primarily stock options and stock appreciation rights) outstanding during each year. The Company applies the two-class method of computing income per share. The two-class method is an earnings allocation formula that determines income per share for common stock and for participating securities, according to dividends declared and participation rights in undistributed earnings. The Company's restricted share awards are considered to be a class of participating security. All per share data has been restated to reflect the 5% stock dividend distributed in December 2011.

Summary Of Significant Accounting Policies (Policy)

12 Months Ended

Dec. 31, 2011

Summary Of Significant Accounting Policies [Abstract]

Nature of Operations

Commerce Bancshares, Inc. and its subsidiaries (the Company) conducts its principal activities from approximately 360 locations throughout Missouri, Illinois, Kansas, Oklahoma and Colorado. Principal activities include retail and commercial banking, investment management, securities brokerage, mortgage banking, credit related insurance and private equity investment activities.

Basis Of Presentation

Basis of Presentation

The Company follows accounting principles generally accepted in the United States of America (GAAP) and reporting practices applicable to the banking industry. The preparation of financial statements under GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and notes. These estimates are based on information available to management at the time the estimates are made. While the consolidated financial statements reflect management's best estimates and judgments, actual results could differ from those estimates. The consolidated financial statements include the accounts of the Company and its majority-owned subsidiaries (after elimination of all material intercompany balances and transactions). Certain amounts for prior years have been reclassified to conform to the current year presentation. Such reclassifications had no effect on net income or total assets.

Cash And Cash Equivalent

Cash and Cash Equivalents

In the accompanying consolidated statements of cash flows, cash and cash equivalents include "Cash and due from banks", "Short-term federal funds sold and securities purchased under agreements to resell", and "Interest earning deposits with banks" as segregated in the accompanying consolidated balance sheets.

Loans And Related Earnings

Loans and Related Earnings

Loans that management has the intent and ability to hold for the foreseeable future or until maturity or pay-off are reported at their outstanding principal balances, net of undisbursed loan proceeds, the allowance for loan losses, and any deferred fees and costs on originated loans. Origination fee income received on loans and amounts representing the estimated direct costs of origination are deferred and amortized to interest income over the life of the loan using the interest method. Prepayment premium or yield maintenance agreements are generally required on all term commercial loans with fixed rate intervals of three years or more.

Interest on loans is accrued based upon the principal amount outstanding. Interest income is recognized primarily on the level yield method. Loan and commitment fees, net of costs, are deferred and recognized in income over the term of the loan or commitment as an adjustment of yield. Annual fees charged on credit card loans are capitalized to principal and amortized over 12 months to loan fees and sales in the accompanying consolidated income statements. Other credit card fees, such as cash advance fees and late payment fees, are recognized in income as an adjustment of yield when charged to the cardholder's account.

Non-Accrual Loans

Loans are placed on non-accrual status when management does not expect to collect payments consistent with acceptable and agreed upon terms of repayment. Business, construction real estate, business real estate, and personal real estate loans that are contractually 90 days past due as to principal and/or interest payments are generally placed on non-accrual, unless they are both well-secured and in the process of collection. Consumer, revolving home equity and credit card loans are exempt under regulatory rules from being classified as non-accrual. When a loan is placed on non-accrual status, any interest previously accrued but not collected is reversed against current income, and the loan is charged off to the extent uncollectible. Principal and interest payments received on non-accrual loans are generally applied to principal. Interest is included in income only after all previous loan charge-offs have been recovered and is recorded only as received. The loan is returned to accrual status only when the borrower has brought all past due principal and interest payments current and, in the opinion of management, the borrower has demonstrated the ability to make future payments of principal and interest as scheduled. A six month history of sustained payment performance is generally required before reinstatement of accrual status.

Restructured Loans

A loan is accounted for as a troubled debt restructuring if the Company, for economic or legal reasons related to the borrowers' financial difficulties, grants a concession to the borrower that it would not otherwise consider. A troubled debt restructuring typically involves a modification of terms such as a reduction of the stated interest rate or face amount of the loan, a reduction of accrued interest, or an extension of the maturity date at a stated interest rate lower than the current market rate for a new loan with similar risk. The Company measures the impairment loss of a troubled debt restructuring based on the difference between the original loan's carrying amount and the present value of expected future cash flows discounted at the original, contractual rate of the loan. Business, business real estate, construction real estate and personal real estate loans whose terms have been modified in a troubled debt restructuring with impairment charges are generally placed on non-accrual status. Other loans identified as troubled debt restructurings were so designated because they were renewed at interest rates that were not deemed to represent current market rates for debt of similar risk. These loans are performing under their modified terms, and interest continues to be accrued and recognized in income. Troubled debt restructurings also include certain credit card loans which have been modified under various debt management and assistance programs.

Impaired Loans

Loans are evaluated regularly by management for impairment. Included in impaired loans are all non-accrual loans, as well as loans whose terms have been modified in a troubled debt restructuring, as discussed above. Once a loan has been identified as impaired, impairment is measured based on either the present value of the expected future cash flows at the loan's initial effective interest rate or the fair value of the collateral if collateral dependent. Factors considered in determining impairment include delinquency status, cash flow analysis, credit analysis, and collateral value and availability.

Loans Held For Sale

Loans Held for Sale

Loans held for sale include student loans and fixed rate residential mortgage loans. These loans are typically classified as held for sale upon origination based upon management's intent to sell all the production of these loans. They are carried at the lower of aggregate cost or fair value. Fair value is determined based on prevailing market prices for loans with similar characteristics, sale contract prices, or, for those portfolios for which management has concerns about contractual performance, discounted cash flow analyses. Declines in fair value below cost (and subsequent recoveries) are recognized in loan fees and sales. Deferred fees and costs related to these loans are not amortized but are recognized as part of the cost basis of the loan at the time it is sold. Gains or losses on sales are recognized upon delivery and included in loan fees and sales.

Allowance/Provision For Loan Losses

Allowance/Provision for Loan Losses

The allowance for loan losses is maintained at a level believed to be appropriate by management to provide for probable loan losses inherent in the portfolio as of the balance sheet date, including losses on known or anticipated problem loans as well as for loans which are not currently known to require specific allowances. Management has established a process to determine the amount of the allowance for loan losses which assesses the risks and losses inherent in its portfolio. Business, construction real estate and business real estate loans are normally larger and more complex, and their collection rates are harder to predict. These loans are more likely to be collateral dependent and are allocated a larger reserve, due to their potential volatility. Personal real estate, credit card, consumer and revolving home equity loans are individually smaller and perform in a more homogenous manner, making loss estimates more predictable. Management's process provides an allowance consisting of a specific allowance component based on certain individually evaluated loans and a general component based on estimates of reserves needed for pools of loans.

Loans subject to individual evaluation generally consist of business, construction real estate, business real estate and personal real estate loans on non-accrual status. These impaired loans are evaluated individually for the impairment of repayment potential and collateral adequacy, and in conjunction with current economic conditions and loss experience, allowances are estimated. Certain other impaired loans identified as troubled debt restructurings are collectively evaluated because they have similar risk characteristics. Loans which have not been identified as impaired are segregated by loan type and sub-type and are collectively evaluated. Reserves calculated for these loan pools are estimated using a consistent methodology that considers historical loan loss experience by loan type, delinquencies, current economic factors, loan risk ratings and industry concentrations.

The Company's estimate of the allowance for loan losses and the corresponding provision for loan losses is based on various judgments and assumptions made by management. The amount of the allowance for loan losses is highly dependent on management's estimates affecting valuation, appraisal of collateral, evaluation of performance and status, and the amount and timing of future cash flows expected to be received on impaired loans. Factors that influence these judgments include past loan loss experience, current loan portfolio composition and characteristics, trends in portfolio risk ratings, levels of non-performing assets, prevailing regional and national economic conditions, and the Company's ongoing loan review process.

The estimates, appraisals, evaluations, and cash flows utilized by management may be subject to frequent adjustments due to changing economic prospects of borrowers or properties. These estimates are reviewed periodically and adjustments, if necessary, are recorded in the provision for loan losses in the periods in which they become known.

Loans, or portions of loans, are charged off to the extent deemed uncollectible. Loan charge-offs reduce the allowance for loan losses, and recoveries of loans previously charged off are added back to the allowance. Business, business real estate, construction real estate and personal real estate loans are generally charged down to estimated collectible balances when they are placed on non-accrual status. Consumer loans and related accrued interest are normally charged down to the fair value of related collateral (or are charged off in full if no collateral) once the loans are more than 120 days delinquent. Credit card loans are charged off against the allowance for loan losses when the receivable is more than 180 days past due. The interest and fee income previously capitalized but not collected on credit card charge-offs is reversed against interest income.

Operating, Direct Financing And Sales Type Leases

Operating, Direct Financing and Sales Type Leases

The net investment in direct financing and sales type leases is included in loans on the Company's consolidated balance sheets, and consists of the present values of the sum of the future minimum lease payments and estimated residual value of the leased asset. Revenue consists of interest earned on the net investment and is recognized over the lease term as a constant percentage return thereon. The net investment in operating leases is included in other assets on the Company's consolidated balance sheets. It is carried at cost, less the amount depreciated to date. Depreciation is recognized, on the straight-line basis, over the lease term to the estimated residual value. Operating lease revenue consists of the contractual lease payments and is recognized over the lease term in other non-interest income. Estimated residual values are established at lease inception utilizing contract terms, past customer experience, and general market data and are reviewed and adjusted, if necessary, on an annual basis.

Investments In Debt And Equity Securities

Investments in Debt and Equity Securities

The Company has classified the majority of its investment portfolio as available for sale. From time to time, the Company sells securities and utilizes the proceeds to reduce borrowings, fund loan growth, or modify its interest rate profile. Securities classified as available for sale are carried at fair value. Changes in fair value, excluding certain losses associated with other-than-temporary impairment (OTTI), are reported in other comprehensive income (loss), a component of stockholders' equity. Securities are periodically evaluated for OTTI in accordance with guidance provided in ASC 320-10-35. For securities with OTTI, the entire loss in fair value is required to be recognized in current earnings if the Company intends to sell the securities or believes it likely that it will be required to sell the security before the anticipated recovery. If neither condition is met, but the Company does not expect to recover the amortized cost basis, the Company determines whether a credit loss has occurred, and the loss is then recognized in current earnings. The noncredit-related portion of the overall loss is reported in other comprehensive income (loss). Mortgage and asset-backed securities whose credit ratings are below AA at their purchase date are evaluated for OTTI under ASC 325-40-35, which requires evaluations for OTTI at purchase date and in subsequent periods. Gains and losses realized upon sales of securities are calculated using the specific identification method and are included in Investment securities gains (losses), net in the consolidated statements of income. Premiums and discounts are amortized to interest income over the estimated lives of the securities. Prepayment experience is continually evaluated to determine the appropriate estimate of the future rate of prepayment. When a change in a bond's estimated remaining life is necessary, a corresponding adjustment is made in the related amortization of premium or discount accretion.

Non-marketable securities include certain private equity investments, consisting of both debt and equity instruments. These securities are carried at fair value in accordance with ASC 946-10-15, with changes in fair value reported in current earnings. In the absence of readily ascertainable market values, fair value is estimated using internally developed models. Changes in fair value and gains and losses from sales are included in Investment securities gains (losses), net. Other non-marketable securities acquired for debt and regulatory purposes are accounted for at cost.

Trading account securities, which are bought and held principally for the purpose of resale in the near term, are carried at fair value. Gains and losses, both realized and unrealized, are recorded in non-interest income.

Purchases and sales of securities are recognized on a trade date basis. A receivable or payable is recognized for pending transaction settlements.

Securities Purchased Under Agreements To Resell And Securities Sold Under Agreements To Repurchase

Securities Purchased under Agreements to Resell and Securities Sold under Agreements to Repurchase

The Company periodically enters into investments of securities under agreements to resell with large financial institutions. These agreements are accounted for as collateralized financing transactions. Securities pledged by the counterparties to secure these agreements are delivered to a third party custodian. Collateral is valued daily, and the Company may require counterparties to deposit additional collateral, or the Company may return collateral pledged when appropriate to maintain full collateralization for these transactions. At December 31, 2011, the Company had entered into $850.0 million of long-term agreements to resell and had accepted securities valued at $894.4 million as collateral.

Securities sold under agreements to repurchase are offered to cash management customers as an automated, collateralized investment account and totaled $702.8 million at December 31, 2011. Securities sold are also used by the Bank to obtain additional borrowed funds at favorable rates, and at December 31, 2011, such securities sold totaled $400.0 million of long-term structured repurchase agreements. As of December 31, 2011, the Company had pledged $2.0 billion of available for sale securities as collateral for repurchase agreements.

Land, Buildings And Equipment

Land, Buildings and Equipment

Land is stated at cost, and buildings and equipment are stated at cost, including capitalized interest when appropriate, less accumulated depreciation. Depreciation is computed using straight-line and accelerated methods. The Company generally assigns depreciable lives of 30 years for buildings, 10 years for building improvements, and 3 to 8 years for equipment. Leasehold improvements are amortized over the shorter of their estimated useful lives or remaining lease terms. Maintenance and repairs are charged to non-interest expense as incurred.

Foreclosed Assets

Foreclosed assets consist of property that has been repossessed and is comprised of commercial and residential real estate and other non-real estate property, including auto and recreational and marine vehicles. The assets are initially recorded at fair value less estimated selling costs, with any valuation adjustments charged to the allowance for loan losses. Fair values are estimated primarily based on appraisals when available or quoted market prices of liquid assets. After their initial recognition, foreclosed assets are valued at the lower of the amount recorded at acquisition date or the current fair value less estimated costs to sell. Any resulting valuation adjustments, in addition to gains and losses realized on sales and net operating expenses, are recorded in other non-interest expense.

Derivatives

The Company is exposed to market risk, including changes in interest rates and currency exchange rates. To manage the volatility relating to these exposures, the Company's risk management policies permit its use of derivative products. The Company manages potential credit exposure through established credit approvals, risk control limits and other monitoring procedures. The Company uses derivatives on a limited basis mainly to stabilize interest rate margins and hedge against interest rate movements. The Company more often manages normal asset and liability positions by altering the products it offers and by selling portions of specific loan or investment portfolios as necessary.

Derivative accounting guidance requires that all derivative financial instruments be recorded on the balance sheet at fair value, with the adjustment to fair value recorded in current earnings. Derivatives that are part of a qualifying hedging relationship under ASC 815-20-25 can be designated, based on the exposure being hedged, as fair value or cash flow hedges. Under the fair value hedging model, gains or losses attributable to the change in fair value of the derivative, as well as gains and losses attributable to the change in fair value of the hedged item, are recognized in current earnings. Under the cash flow hedging model, the effective portion of the gain or loss related to the derivative is recognized as a component of other comprehensive income. The ineffective portion is recognized in current earnings.

The Company formally documents all hedging relationships between hedging instruments and the hedged item, as well as its risk management objective. At December 31, 2011, the Company had three interest rate swaps designated as fair value hedges. The Company performs quarterly assessments, using the regression method, to determine whether the hedging relationship has been highly effective in offsetting changes in fair values.

Derivative contracts are also offered to customers to assist in hedging their risks of adverse changes in interest rates and foreign exchange rates. The Company serves as an intermediary between its customers and the markets. Each contract between the Company and its customers is offset by a contract between the Company and various counterparties. These contracts do not qualify for hedge accounting. They are carried at fair value, with changes in fair value recorded in other non-interest income. As each customer contract is paired with an offsetting contract, the impact to net income is minimized.

The Company enters into interest rate lock commitments on mortgage loans, which are commitments to originate loans whereby the interest rate on the loan is determined prior to funding. The Company also has corresponding forward sales contracts related to these interest rate lock commitments. Both the mortgage loan commitments and the related sales contracts are accounted for as derivatives and carried at fair value, with changes in fair value recorded in loan fees and sales. Fair values are based upon quoted prices, and fair value measurements of mortgage loan commitments include the value of loan servicing rights.

Income Taxes

Amounts provided for income tax expense are based on income reported for financial statement purposes and do not necessarily represent amounts currently payable under tax laws. Deferred income taxes are provided for temporary differences between the financial reporting bases and income tax bases of the Company's assets and liabilities, net operating losses, and tax credit carryforwards. Deferred tax assets and liabilities are measured using the enacted tax rates that are expected to apply to taxable income when such assets and liabilities are anticipated to be settled or realized. The effect on deferred tax assets and liabilities of a change in tax rates is recognized as tax expense or benefit in the period that includes the enactment date of the change. In determining the amount of deferred tax assets to recognize in the financial statements, the Company evaluates the likelihood of realizing such benefits in future periods. A valuation allowance is established if it is more likely than not that all or some portion of the deferred tax asset will not be realized. The Company recognizes interest and penalties related to income taxes within income tax expense in the consolidated statements of income.

The Company and its eligible subsidiaries file a consolidated federal income tax return. State and local income tax returns are filed on a combined, consolidated or separate return basis based upon each jurisdiction's laws and regulations.

Intangible Assets

Goodwill and intangible assets that have indefinite useful lives are not amortized, but are tested annually for impairment. Intangible assets that have finite useful lives, such as core deposit intangibles and mortgage servicing rights, are amortized over their estimated useful lives. Core deposit intangibles are amortized over periods of 8 to 14 years, representing their estimated lives, using accelerated methods. Mortgage servicing rights are amortized in proportion to and over the period of estimated net servicing income, considering appropriate prepayment assumptions.

When facts and circumstances indicate potential impairment of amortizable intangible assets, the Company evaluates the recoverability of the asset carrying value, using estimates of undiscounted future cash flows over the remaining asset life. Any impairment loss is measured by the excess of carrying value over fair value. Goodwill impairment tests are performed on an annual basis or when events or circumstances dictate. In these tests, the fair value of each reporting unit, or segment, is compared to the carrying amount of that reporting unit in order to determine if impairment is indicated. If so, the implied fair value of the reporting unit's goodwill is compared to its carrying amount, and the impairment loss is measured by the excess of the carrying value over fair value. There has been no impairment resulting from goodwill impairment tests. However, adverse changes in the economic environment, operations of the reporting unit, or other factors could result in a decline in the implied fair value.

Pension Plan

The Company's pension plan is described in Note 9, Employee Benefit Plans. The funded status of the plan is recognized as an asset or liability in the balance sheet, and changes in that funded status are recognized in the year in which the changes occur through other comprehensive income. Plan assets and benefit obligations are measured as of fiscal year end. The measurement of the projected benefit obligation and pension expense involve actuarial valuation methods and the use of various actuarial and economic assumptions. The Company monitors the assumptions and updates them periodically. Due to the long-term nature of the pension plan obligation, actual results may differ significantly from estimations. Such differences are adjusted over time as the assumptions are replaced by facts and values are recalculated.

Stock-Based Compensation

The Company's stock-based employee compensation plan is described in Note 10, Stock-Based Compensation and Directors Stock Purchase Plan. In accordance with the requirements of ASC 718-10-30-3 and 35-2, the Company measures the cost of stock-based compensation based on the grant-date fair value of the award, recognizing the cost over the requisite service period. The fair value of an award is estimated using the Black-Scholes option-pricing model. The expense recognized is based on an estimation of the number of awards for which the requisite service is expected to be rendered and is included in salaries and employee benefits in the accompanying consolidated statements of income.

Treasury Stock

Purchases of the Company's common stock are recorded at cost. Upon re-issuance for acquisitions, exercises of stock-based awards or other corporate purposes, treasury stock is reduced based upon the average cost basis of shares held.

Income Per Share

Income per Share

Basic income per share is computed using the weighted average number of common shares outstanding during each year. Diluted income per share includes the effect of all dilutive potential common shares (primarily stock options and stock appreciation rights) outstanding during each year. The Company applies the two-class method of computing income per share. The two-class method is an earnings allocation formula that determines income per share for common stock and for participating securities, according to dividends declared and participation rights in undistributed earnings. The Company's restricted share awards are considered to be a class of participating security. All per share data has been restated to reflect the 5% stock dividend distributed in December 2011.