New Authoritative Accounting Guidance (Policies)	9 Months Ended
Sep. 30, 2020
Accounting Changes and Error Corrections [Abstract]
Basis of Presentation	The unaudited consolidated financial statements of Valley National Bancorp, a New Jersey corporation (Valley), include the accounts of its commercial bank subsidiary, Valley National Bank (the Bank), and all of Valley’s direct or indirect wholly-owned subsidiaries. All inter-company transactions and balances have been eliminated. The accounting and reporting policies of Valley conform to U.S. generally accepted accounting principles (U.S. GAAP) and general practices within the financial services industry. In accordance with applicable accounting standards, Valley does not consolidate statutory trusts established for the sole purpose of issuing trust preferred securities and related trust common securities.
Reclassification	Certain prior period amounts have been reclassified to conform to the current presentation.
Significant Estimates	Significant Estimates. In preparing the unaudited consolidated financial statements in conformity with U.S. GAAP, management has made estimates and assumptions that affect the reported amounts of assets and liabilities as of the date of the consolidated statements of financial condition and results of operations for the periods indicated. Material estimates that require application of management’s most difficult, subjective or complex judgment and are particularly susceptible to change include: the allowance for credit losses, the evaluation of goodwill and other intangible assets for impairment, and income taxes. Estimates and assumptions are reviewed periodically, and the effects of revisions are reflected in the consolidated financial statements in the period they are deemed necessary. While management uses its best judgment, actual amounts or results could differ significantly from those estimates. The current economic environment has increased the degree of uncertainty inherent in these material estimates. Actual results may differ from those estimates. Also, future amounts and values could differ materially from those estimates due to changes in values and circumstances after the balance sheet date.
New Accounting Guidance Adopted and Not Yet Adopted	New Accounting Guidance Adopted in 2020 Accounting Standards Update (ASU) No. 2016-13, "Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments" amends the accounting guidance on the impairment of financial instruments. The FASB issued an amendment to replace the incurred loss impairment methodology under prior accounting guidance with a new current expected credit loss (CECL) model. The measurement of expected credit losses is based on relevant information about past events, including historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. Valley utilizes a two-year reasonable and supportable forecast period followed by a one-year period over which estimated losses revert to historical loss experience for the remaining life of the loan. The measurement of expected credit loss under the CECL methodology is applicable to financial assets measured at amortized cost, including loans, held to maturity investments and purchased financial assets with credit deterioration (PCD) assets. It also applies to certain off-balance sheet credit exposures. Valley adopted ASU No. 2016-13 on January 1, 2020 using the modified retrospective approach for all financial assets measured at amortized cost (except for PCD loans) and off-balance sheet credit exposures. Valley has established a governance structure to implement the CECL accounting guidance and has developed a methodology and set of models to be used. At adoption, Valley recorded a $100.4 million increase to its allowance for credit losses, including reserves of $92.5 million, $7.1 million and $793 thousand related to loans, unfunded credit commitments and held to maturity debt securities, respectively. Of the $92.5 million in loan reserves, $61.6 million represents PCD loan related reserves which were recognized through a gross-up that increases the amortized cost basis of loans with a corresponding increase to the allowance for credit losses, and therefore results in no impact to shareholders' equity. The remaining non-credit discount of $97.7 million related to PCD loans is accreted into interest income over the life of the loans at the effective interest rate effective January 1, 2020. The non-PCD loan related increase to the allowance for credit losses of $38.8 million, including the reserves for unfunded loan commitments and held to maturity debt securities, was offset in shareholders' equity and deferred tax assets. For regulatory capital purposes, in connection with the Federal Reserve Board’s final interim rule as of April 3, 2020, 100 percent of the CECL Day 1 impact to shareholders' equity equaling $28.2 million after-tax will be deferred over a two-year period ending January 1, 2022, at which time it will be phased in on a pro-rata basis over a three-year period ending January 1, 2025. Additionally, 25 percent of the reserve build (i.e., provision for credit losses less net charge-offs) net of taxes will be phased in over the same time frame. ASU No. 2017-04, "Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment" eliminates the requirement to calculate the implied fair value of goodwill (i.e., Step 2 of the current goodwill impairment test guidance) to measure a goodwill impairment charge. Instead, an entity will be required to record an impairment charge based on the excess of a reporting unit’s carrying amount over its fair value (i.e., measure the charge based on Step 1 of the current guidance). In addition, ASU No. 2017-04 eliminates the requirements for any reporting unit with a zero or negative carrying amount to perform a qualitative assessment and, if it fails that qualitative test, to perform Step 2 of the goodwill impairment test. However, an entity will be required to disclose the amount of goodwill allocated to each reporting unit with a zero or negative carrying amount of net assets. An entity still has the option to perform the qualitative assessment for a reporting unit to determine if the quantitative impairment test is necessary. ASU No. 2017-04 was effective for Valley on January 1, 2020 and Valley applied this new guidance in its annual goodwill impairment test performed during the second quarter 2020. New Accounting Guidance issued in 2020 ASU No. 2020-08, "Codification Improvements to Subtopic 310-20, Receivables—Nonrefundable Fees and Other Costs" provides clarification and affects the guidance previously issued by ASU No. 2017-08 “Receivables -Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities.” ASU No. 2020-08 clarifies that an entity should reevaluate whether a debt security with multiple call dates is within the scope of paragraph 310-20-35-33. For each reporting period, to the extent that the amortized cost basis of an individual callable debt security exceeds the amount repayable by the issuer at the next call date, the premium should be amortized to the next call date, unless the guidance to consider estimated prepayments is applied. ASU No. 2020-08 will be effective for Valley for the annual and interim periods beginning January 1, 2021 and early adoption is not permitted. This new guidance is not expected to have a significant impact on Valley’s consolidated financial statements. ASU No. 2020-04, "Reference Rate Reform (Topic 848)" provides optional expedients and exceptions for applying U.S. GAAP to contract modifications and hedging relationships that reference LIBOR or another reference rate expected to be discontinued, subject to meeting certain criteria. Under the new guidance, an entity can elect by accounting topic or industry subtopic to account for the modification of a contract affected by reference rate reform as a continuation of the existing contract, if certain conditions are met. In addition, the new guidance allows an entity to elect on a hedge-by-hedge basis to continue to apply hedge accounting for hedging relationships in which the critical terms change due to reference rate reform, if certain conditions are met. A one-time election to sell and/or transfer held-to-maturity debt securities that reference a rate affected by reference rate reform is also allowed. ASU No. 2020-04 became effective for all entities as of March 12, 2020 and will apply to all LIBOR reference rate modifications through December 31, 2022. Management is currently evaluating the impact of the ASU on Valley’s consolidated financial statements.
Impairment Analysis of Available For Sale Debt Securities and Allowance for Credit Losses for Held to Maturity Debt Securities	Impairment Analysis of Available For Sale Debt Securities Valley's available for sale debt securities portfolio includes corporate bonds and special revenue bonds, among other securities. These type of securities may pose a higher risk of future impairment charges by Valley as a result of the unpredictable nature of the U.S. economy and its potential negative effect on the future performance of the security issuers, including due to the economic effects of COVID-19. Available for sale debt securities in unrealized loss positions are evaluated for impairment related to credit losses on a quarterly basis. In performing an assessment of whether any decline in fair value is due to a credit loss, Valley considers the extent to which the fair value is less than the amortized cost, changes in credit ratings, any adverse economic conditions, as well as all relevant information at the individual security level such as credit deterioration of the issuer or collateral underlying the security. In assessing the impairment, Valley compares the present value of cash flows expected to be collected with the amortized cost basis of the security. If it is determined that the decline in fair value was due to credit losses, an allowance for credit losses is recorded, limited to the amount the fair value is less than amortized cost basis. The non-credit related decrease in the fair value, such as a decline due to changes in market interest rates, is recorded in other comprehensive income, net of tax. Valley also assesses the intent to sell the securities (as well as the likelihood of a near-term recovery). If Valley intends to sell an available for sale debt security or it is more likely than not that Valley will be required to sell the security before recovery of its amortized cost basis, the debt security is written down to its fair value and the write down is charged to the debt security’s fair value at the reporting date with any incremental impairment reported in earnings. The obligations of states and political subdivisions classified as available for sale include special revenue bonds which had an aggregate amortized cost and fair value of $70.6 million and $71.9 million, respectively, at September 30, 2020. The gross unrealized losses associated with the special revenue bonds as of September 30, 2020 were not material. Approximately 41 percent of the special revenue bonds were issued by the states of (or municipalities within) Utah and Illinois. As part of Valley’s pre-purchase analysis and on-going quarterly assessment of impairment of the obligations of states and political subdivisions, the Credit Risk Management Department conducts a financial analysis and risk rating assessment of each security issuer based on the issuer’s most recently issued financial statements and other publicly available information. These investments are a mix of municipal bonds with investment grade ratings or non-rated revenue bonds paying in accordance with their contractual terms. The vast majority of the bonds not rated by the rating agencies are state housing finance agency revenue bonds secured by Ginnie Mae securities that are commonly referred to as Tax Exempt Mortgage Securities (TEMS). Valley continues to monitor the special revenue bond portfolio as part of its quarterly impairment analysis. Valley has evaluated available for sale debt securities that are in an unrealized loss position as of September 30, 2020 included in the table above and has determined that the declines in fair value are mainly attributable to market volatility, not credit quality or other factors. Based on a comparison of the present value of expected cash flows to the amortized cost, management recognized no impairment during the three and nine months ended September 30, 2020 and, as a result, there was no allowance for credit losses for available for sale debt securities at September 30, 2020. During the nine months ended September 30, 2019, Valley recognized a $2.9 million other-than-temporary credit impairment charge on one special revenue bond classified as available for sale (within the obligations of states and state agencies in the tables above). The credit impairment was due to severe credit deterioration disclosed by the issuer in the second quarter 2019, as well as the issuer's default on its contractual payment. At September 30, 2020, the non-accruing impaired security had an adjusted amortized cost and fair value of $680 thousand and $783 thousand, respectively. Valley discontinues the recognition of interest on debt securities if the securities meet both of the following criteria: (i) regularly scheduled interest payments have not been paid or have been deferred by the issuer, and (ii) full collection of all contractual principal and interest payments is not deemed to be the most likely outcome, resulting in the recognition of other-than-temporary impairment of the security. Allowance for Credit Losses for Held to Maturity Debt Securities Valley has a zero loss expectation for certain securities within the held to maturity portfolio, and therefore it is not required to estimate an allowance for credit losses related to these securities under the CECL standard. After an evaluation of qualitative factors, Valley identified the following securities types which it believes qualify for this exclusion: U.S. Treasury securities, U.S. agency securities, residential mortgage-backed securities issued by Ginnie Mae, Fannie Mae and Freddie Mac, and collateralized municipal bonds called TEMS. To measure the expected credit losses on held to maturity debt securities that have loss expectations, Valley estimates the expected credit losses using a discounted cash flow model developed by a third-party. Assumptions used in the model for pools of securities with common risk characteristics include the historical lifetime probability of default and severity of loss in the event of default, with the model incorporating several economic cycles of loss history data to calculate expected credit losses given default at the individual security level. The model is adjusted for a probability weighted multi-scenario economic forecast to estimate future credit losses. Valley uses a two-year reasonable and supportable forecast period followed by a one-year period over which estimated losses revert to historical loss experience for the remaining life of the investment security. The economic forecast methodology and governance for debt securities is aligned with Valley's economic forecast used for the loan portfolio discussed in more detail in Note 8. Allowance for Loan Losses The allowance for loan losses is a valuation account that is deducted from loans' amortized cost basis to present the net amount expected to be collected on loans. Valley's methodology to establish the allowance for loan losses has two basic components: (1) a collective (pooled) reserve component for estimated lifetime expected credit losses for pools of loans that share similar risk characteristics and (2) an individual reserve component for loans that do not share common risk characteristics. Reserves for loans that share common risk characteristics. In estimating the component of the allowance on a collective basis, Valley uses a transition matrix model which calculates an expected life of loan loss percentage for each loan pool by generating probability of default and loss given default metrics. The metrics are based on the migration of loans from performing to loss by credit quality rating or delinquency categories using historical life-of-loan analysis periods for each loan portfolio pool, and the severity of loss, based on the aggregate net lifetime losses incurred. The model's expected losses based on loss history are adjusted for qualitative factors. Among other things, these adjustments include and account for differences in: (i) lending policies and procedures, (ii) current business conditions and economic developments that affect the loan collectability, (iii) concentration risks by size, type, and geography, (iv) the potential volume and migration of loan forbearances to non-performing status, and (v) the effect of external factors such as legal and regulatory requirements on the level of estimated credit losses in the existing portfolio. Valley utilizes a two-year reasonable and supportable forecast period followed by a one-year period over which estimated losses revert to historical loss experience for the remaining life of the loan. The forecasts consist of a multi-scenario economic forecast model to estimate future credit losses that is governed by a cross-functional committee. The committee meets each quarter to determine which economic scenarios developed by Moody's will be incorporated into the model, as well as the relative probability weightings of the selected scenarios, based upon all readily available information. The model projects economic variables under each scenario based on detailed statistical analyses. Valley has identified and selected key variables that most closely correlated to its historical credit performance, which include: GDP, unemployment and the Case-Shiller Home Price Index. Reserves for loans that that do not share common risk characteristics. Valley measures specific reserves for individual loans that do not share common risk characteristics with other loans, consisting of collateral dependent, TDR, and expected TDR loans, based on the amount of lifetime expected credit losses calculated on those loans and charge-offs of those amounts determined to be uncollectible. Factors considered by Valley in measuring the extent of expected credit loss include payment status, collateral value, borrower financial condition, guarantor support and the probability of collecting scheduled principal and interest payments when due. If repayment is based upon future expected cash flows, the present value of the expected future cash flows discounted at the loan’s original effective interest rate is compared to the carrying value of the loan, and any shortfall is recorded as the allowance for credit losses. The effective interest rate used to discount expected cash flows is adjusted to incorporate expected prepayments, if applicable. When Valley determines that foreclosure is probable, collateral dependent loan balances are written down to the estimated current fair value (less estimated selling costs) of each loan’s underlying collateral resulting in an immediate charge-off to the allowance, excluding any consideration for personal guarantees that may be pursued in the Bank’s collection process. Valley elected a practical expedient to use the estimated current fair value (less estimated selling costs) of the collateral to measure expected credit losses on collateral dependent loans when foreclosure is not probable.Allowance for Unfunded Credit CommitmentsThe allowance for unfunded credit commitments generally consists of undisbursed non-cancellable lines of credit, new loan commitments and commercial letters of credit valued using a similar methodology as used for loans. Management's estimate of expected losses inherent in these off-balance sheet credit exposures also incorporates estimated usage factors over the commitment's contractual period or an expected pull-through rate for new loan commitments. The allowance for unfunded credit commitments totaling $10.3 million at September 30, 2020 is included in accrued expenses and other liabilities on the consolidated statements of financial condition.

New Authoritative Accounting Guidance (Policies)

9 Months Ended

Sep. 30, 2020

Accounting Changes and Error Corrections [Abstract]

The unaudited consolidated financial statements of Valley National Bancorp, a New Jersey corporation (Valley), include the accounts of its commercial bank subsidiary, Valley National Bank (the Bank), and all of Valley’s direct or indirect wholly-owned subsidiaries. All inter-company transactions and balances have been eliminated. The accounting and reporting policies of Valley conform to U.S. generally accepted accounting principles (U.S. GAAP) and general practices within the financial services industry. In accordance with applicable accounting standards, Valley does not consolidate statutory trusts established for the sole purpose of issuing trust preferred securities and related trust common securities.

Reclassification

Certain prior period amounts have been reclassified to conform to the current presentation.

Significant Estimates

Significant Estimates. In preparing the unaudited consolidated financial statements in conformity with U.S. GAAP, management has made estimates and assumptions that affect the reported amounts of assets and liabilities as of the date of the consolidated statements of financial condition and results of operations for the periods indicated. Material estimates that require application of management’s most difficult, subjective or complex judgment and are particularly susceptible to change include: the allowance for credit losses, the evaluation of goodwill and other intangible assets for impairment, and income taxes. Estimates and assumptions are reviewed periodically, and the effects of revisions are reflected in the consolidated financial statements in the period they are deemed necessary. While management uses its best judgment, actual amounts or results could differ significantly from those estimates. The current economic environment has increased the degree of uncertainty inherent in these material estimates. Actual results may differ from those estimates. Also, future amounts and values could differ materially from those estimates due to changes in values and circumstances after the balance sheet date.

New Accounting Guidance Adopted and Not Yet Adopted

New Accounting Guidance Adopted in 2020

Accounting Standards Update (ASU) No. 2016-13, "Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments" amends the accounting guidance on the impairment of financial instruments. The FASB issued an amendment to replace the incurred loss impairment methodology under prior accounting guidance with a new current expected credit loss (CECL) model. The measurement of expected credit losses is based on relevant information about past events, including historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. Valley utilizes a two-year reasonable and supportable forecast period followed by a one-year period over which estimated losses revert to historical loss experience for the remaining life of the loan. The measurement of expected credit loss under the CECL methodology is applicable to financial assets measured at amortized cost, including loans, held to maturity investments and purchased financial assets with credit deterioration (PCD) assets. It also applies to certain off-balance sheet credit exposures.

Valley adopted ASU No. 2016-13 on January 1, 2020 using the modified retrospective approach for all financial assets measured at amortized cost (except for PCD loans) and off-balance sheet credit exposures. Valley has established a governance structure to implement the CECL accounting guidance and has developed a methodology and set of models to be used. At adoption, Valley recorded a $100.4 million increase to its allowance for credit losses, including reserves of $92.5 million, $7.1 million and $793 thousand related to loans, unfunded credit commitments and held to maturity debt securities, respectively. Of the $92.5 million in loan reserves, $61.6 million represents PCD loan related reserves which were recognized through a gross-up that increases the amortized cost basis of loans with a corresponding increase to the allowance for credit losses, and therefore results in no impact to shareholders' equity. The remaining non-credit discount of $97.7 million related to PCD loans is accreted into interest income over the life of the loans at the effective interest rate effective January 1, 2020. The non-PCD loan related increase to the allowance for credit losses of $38.8 million, including the reserves for unfunded loan commitments and held to maturity debt securities, was offset in shareholders' equity and deferred tax assets.

For regulatory capital purposes, in connection with the Federal Reserve Board’s final interim rule as of April 3, 2020, 100 percent of the CECL Day 1 impact to shareholders' equity equaling $28.2 million after-tax will be deferred over a two-year period ending January 1, 2022, at which time it will be phased in on a pro-rata basis over a three-year period ending January 1, 2025. Additionally, 25 percent of the reserve build (i.e., provision for credit losses less net charge-offs) net of taxes will be phased in over the same time frame.

ASU No. 2017-04, "Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment" eliminates the requirement to calculate the implied fair value of goodwill (i.e., Step 2 of the current goodwill impairment test guidance) to measure a goodwill impairment charge. Instead, an entity will be required to record an impairment charge based on the excess of a reporting unit’s carrying amount over its fair value (i.e., measure the charge based on Step 1 of the current guidance). In addition, ASU No. 2017-04 eliminates the requirements for any reporting unit with a zero or negative carrying amount to perform a qualitative assessment and, if it fails that qualitative test, to perform Step 2 of the goodwill impairment test. However, an entity will be required to disclose the amount of goodwill allocated to each reporting unit with a zero or negative carrying amount of net assets. An entity still has the option to perform the qualitative assessment for a reporting unit to determine if the quantitative impairment test is necessary. ASU No. 2017-04 was effective for Valley on January 1, 2020 and Valley applied this new guidance in its annual goodwill impairment test performed during the second quarter 2020.

New Accounting Guidance issued in 2020

ASU No. 2020-08, "Codification Improvements to Subtopic 310-20, Receivables—Nonrefundable Fees and Other Costs" provides clarification and affects the guidance previously issued by ASU No. 2017-08 “Receivables -Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities.” ASU No. 2020-08 clarifies that an entity should reevaluate whether a debt security with multiple call

dates is within the scope of paragraph 310-20-35-33. For each reporting period, to the extent that the amortized cost basis of an individual callable debt security exceeds the amount repayable by the issuer at the next call date, the premium should be amortized to the next call date, unless the guidance to consider estimated prepayments is applied. ASU No. 2020-08 will be effective for Valley for the annual and interim periods beginning January 1, 2021 and early adoption is not permitted. This new guidance is not expected to have a significant impact on Valley’s consolidated financial statements.

ASU No. 2020-04, "Reference Rate Reform (Topic 848)" provides optional expedients and exceptions for applying U.S. GAAP to contract modifications and hedging relationships that reference LIBOR or another reference rate expected to be discontinued, subject to meeting certain criteria. Under the new guidance, an entity can elect by accounting topic or industry subtopic to account for the modification of a contract affected by reference rate reform as a continuation of the existing contract, if certain conditions are met. In addition, the new guidance allows an entity to elect on a hedge-by-hedge basis to continue to apply hedge accounting for hedging relationships in which the critical terms change due to reference rate reform, if certain conditions are met. A one-time election to sell and/or transfer held-to-maturity debt securities that reference a rate affected by reference rate reform is also allowed. ASU No. 2020-04 became effective for all entities as of March 12, 2020 and will apply to all LIBOR reference rate modifications through December 31, 2022. Management is currently evaluating the impact of the ASU on Valley’s consolidated financial statements.

Impairment Analysis of Available For Sale Debt Securities and Allowance for Credit Losses for Held to Maturity Debt Securities

Impairment Analysis of Available For Sale Debt Securities

Valley's available for sale debt securities portfolio includes corporate bonds and special revenue bonds, among other securities. These type of securities may pose a higher risk of future impairment charges by Valley as a result of the unpredictable nature of the U.S. economy and its potential negative effect on the future performance of the security issuers, including due to the economic effects of COVID-19.

Available for sale debt securities in unrealized loss positions are evaluated for impairment related to credit losses on a quarterly basis. In performing an assessment of whether any decline in fair value is due to a credit loss, Valley considers the extent to which the fair value is less than the amortized cost, changes in credit ratings, any adverse economic conditions, as well as all relevant information at the individual security level such as credit deterioration of the issuer or collateral underlying the security. In assessing the impairment, Valley compares the present value of cash flows expected to be collected with the amortized cost basis of the security. If it is determined that the decline in fair value was due to credit losses, an allowance for credit losses is recorded, limited to the amount the fair value is less than amortized cost basis. The non-credit related decrease in the fair value, such as a decline due to changes in market interest rates, is recorded in other comprehensive income, net of tax. Valley also assesses the intent to sell the securities (as well as the likelihood of a near-term recovery). If Valley intends to sell an available for sale debt security or it is more likely than not that Valley will be required to sell the security before recovery of its amortized cost basis, the debt security is written down to its fair value and the write down is charged to the debt security’s fair value at the reporting date with any incremental impairment reported in earnings.

The obligations of states and political subdivisions classified as available for sale include special revenue bonds which had an aggregate amortized cost and fair value of $70.6 million and $71.9 million, respectively, at September 30, 2020. The gross unrealized losses associated with the special revenue bonds as of September 30, 2020 were not material. Approximately 41 percent of the special revenue bonds were issued by the states of (or municipalities within) Utah and Illinois. As part of Valley’s pre-purchase analysis and on-going quarterly assessment of impairment of the obligations of states and political subdivisions, the Credit Risk Management Department conducts a financial analysis and risk rating assessment of each security issuer based on the issuer’s most recently issued financial statements and other publicly available information. These investments are a mix of municipal bonds with investment grade ratings or non-rated revenue bonds paying in accordance with their contractual terms. The vast majority of the bonds not rated by the rating agencies are state housing finance agency

revenue bonds secured by Ginnie Mae securities that are commonly referred to as Tax Exempt Mortgage Securities (TEMS). Valley continues to monitor the special revenue bond portfolio as part of its quarterly impairment analysis.

Valley has evaluated available for sale debt securities that are in an unrealized loss position as of September 30, 2020 included in the table above and has determined that the declines in fair value are mainly attributable to market volatility, not credit quality or other factors. Based on a comparison of the present value of expected cash flows to the amortized cost, management recognized no impairment during the three and nine months ended September 30, 2020 and, as a result, there was no allowance for credit losses for available for sale debt securities at September 30, 2020.

During the nine months ended September 30, 2019, Valley recognized a $2.9 million other-than-temporary credit impairment charge on one special revenue bond classified as available for sale (within the obligations of states and state agencies in the tables above). The credit impairment was due to severe credit deterioration disclosed by the issuer in the second quarter 2019, as well as the issuer's default on its contractual payment. At September 30, 2020, the non-accruing impaired security had an adjusted amortized cost and fair value of $680 thousand and $783 thousand, respectively.

Valley discontinues the recognition of interest on debt securities if the securities meet both of the following criteria: (i) regularly scheduled interest payments have not been paid or have been deferred by the issuer, and (ii) full collection of all contractual principal and interest payments is not deemed to be the most likely outcome, resulting in the recognition of other-than-temporary impairment of the security.

Allowance for Credit Losses for Held to Maturity Debt Securities

Valley has a zero loss expectation for certain securities within the held to maturity portfolio, and therefore it is not required to estimate an allowance for credit losses related to these securities under the CECL standard. After an evaluation of qualitative factors, Valley identified the following securities types which it believes qualify for this exclusion: U.S. Treasury securities, U.S. agency securities, residential mortgage-backed securities issued by Ginnie Mae, Fannie Mae and Freddie Mac, and collateralized municipal bonds called TEMS.

To measure the expected credit losses on held to maturity debt securities that have loss expectations, Valley estimates the expected credit losses using a discounted cash flow model developed by a third-party. Assumptions used in the model for pools of securities with common risk characteristics include the historical lifetime probability of default and severity of loss in the event of default, with the model incorporating several economic cycles of loss history data to calculate expected credit losses given default at the individual security level. The model is adjusted for a probability weighted multi-scenario economic forecast to estimate future credit losses. Valley uses a two-year reasonable and supportable forecast period followed by a one-year period over which estimated losses revert to historical loss experience for the remaining life of the investment security. The economic forecast methodology and governance for debt securities is aligned with Valley's economic forecast used for the loan portfolio discussed in more detail in Note 8.

Allowance for Loan Losses

The allowance for loan losses is a valuation account that is deducted from loans' amortized cost basis to present the net amount expected to be collected on loans. Valley's methodology to establish the allowance for loan losses has two basic components: (1) a collective (pooled) reserve component for estimated lifetime expected credit losses for pools of loans that share similar risk characteristics and (2) an individual reserve component for loans that do not share common risk characteristics.

Reserves for loans that share common risk characteristics. In estimating the component of the allowance on a collective basis, Valley uses a transition matrix model which calculates an expected life of loan loss percentage for each loan pool by generating probability of default and loss given default metrics. The metrics are based on the migration of loans from performing to loss by credit quality rating or delinquency categories using historical life-of-loan analysis periods for each loan portfolio pool, and the severity of loss, based on the aggregate net lifetime losses incurred. The model's expected losses based on loss history are adjusted for qualitative factors. Among other things, these adjustments include and account for differences in: (i) lending policies and procedures, (ii) current business conditions and economic developments that affect the loan collectability, (iii) concentration risks by size, type, and geography, (iv) the potential volume and migration of loan forbearances to non-performing status, and (v) the effect of external factors such as legal and regulatory requirements on the level of estimated credit losses in the existing portfolio.

Valley utilizes a two-year reasonable and supportable forecast period followed by a one-year period over which estimated losses revert to historical loss experience for the remaining life of the loan. The forecasts consist of a multi-scenario economic forecast model to estimate future credit losses that is governed by a cross-functional committee. The committee meets each quarter to determine which economic scenarios developed by Moody's will be incorporated into the model, as well as the relative probability weightings of the selected scenarios, based upon all readily available information. The model projects economic variables under each scenario based on detailed statistical analyses. Valley has identified and selected key variables that most closely correlated to its historical credit performance, which include: GDP, unemployment and the Case-Shiller Home Price Index.

Reserves for loans that that do not share common risk characteristics. Valley measures specific reserves for individual loans that do not share common risk characteristics with other loans, consisting of collateral dependent, TDR, and expected TDR loans, based on the amount of lifetime expected credit losses calculated on those loans and charge-offs of those amounts determined to be uncollectible. Factors considered by Valley in measuring the extent of expected credit loss include payment status, collateral value, borrower financial condition, guarantor support and the probability of collecting scheduled principal and interest payments when due. If repayment is based upon future expected cash flows, the present value of the expected future cash flows discounted at the loan’s original effective interest rate is compared to the carrying value of the loan, and any shortfall is recorded as the allowance for credit losses. The effective interest rate used to discount expected cash flows is adjusted to incorporate expected prepayments, if applicable.

When Valley determines that foreclosure is probable, collateral dependent loan balances are written down to the estimated current fair value (less estimated selling costs) of each loan’s underlying collateral resulting in an immediate charge-off to the allowance, excluding any consideration for personal guarantees that may be pursued in

the Bank’s collection process. Valley elected a practical expedient to use the estimated current fair value (less estimated selling costs) of the collateral to measure expected credit losses on collateral dependent loans when foreclosure is not probable.Allowance for Unfunded Credit CommitmentsThe allowance for unfunded credit commitments generally consists of undisbursed non-cancellable lines of credit, new loan commitments and commercial letters of credit valued using a similar methodology as used for loans. Management's estimate of expected losses inherent in these off-balance sheet credit exposures also incorporates estimated usage factors over the commitment's contractual period or an expected pull-through rate for new loan commitments. The allowance for unfunded credit commitments totaling $10.3 million at September 30, 2020 is included in accrued expenses and other liabilities on the consolidated statements of financial condition.