Summary of Significant Accounting Policies and Related Data	12 Months Ended
Feb. 27, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies and Related Data	Summary of Significant Accounting Policies and Related Data Basis of consolidation The consolidated financial statements include the balances of Apogee Enterprises, Inc. and its subsidiaries (Apogee, we, us, our or the Company) after elimination of intercompany balances and transactions. We consolidate variable interest entities related to our New Market Tax Credit transactions as it has been determined that the Company is the primary beneficiary of those entities' operations (refer to Note 10 for more information). Fiscal year Our fiscal year ends on the Saturday closest to the last day of February, or as determined by the Board of Directors. Fiscal 2021, 2020 and 2019 each consisted of 52 weeks. Accounting estimates The preparation of the consolidated financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts in the consolidated financial statements and accompanying notes. Actual results could differ significantly from those estimates. Reclassifications Certain reclassifications of amounts previously reported have been made to the accompanying consolidated results of operations to maintain consistency and comparability between periods presented. These reclassifications had no impact on previously reported operating income or net earnings within the consolidated results of operations. Cash equivalents Highly liquid investments with an original maturity of three months or less are included in cash equivalents and are stated at cost, which approximates fair value. Marketable securities To the extent the amortized cost basis of the available-for-sale securities exceeds the fair value, the Company assesses the debt securities for credit loss. When assessing the risk of credit loss, the Company considers factors such as the severity and the reason of the decline in value, such as any changes to the rating of the security by a rating agency or other adverse conditions specifically related to the security, and management's intended holding period and time horizon for selling. During fiscal 2021, 2020, and 2019, the Company did not recognize any credit losses related to its available-for-sale securities. Further, as of February 27, 2021 and February 29, 2020, the Company did not record an allowance for credit losses related to its available-for-sale securities. Marketable securities are included in other current and non-current assets on the consolidated balance sheets and gross realized gains and losses are included in other income (expense), net in our consolidated results of operations. Inventories Inventories, which consist primarily of purchased glass and aluminum, are valued at lower of cost or market using the first-in, first-out (FIFO) method. Property, plant and equipment Property, plant and equipment (PP&E) is recorded at cost. Significant improvements and renewals that extend the useful life of the asset are capitalized. Repairs and maintenance are charged to expense as incurred. When an asset is retired or otherwise disposed of, the cost and related accumulated depreciation are removed from the accounts and any related gains or losses are included in selling, general and administrative expenses. Long-lived assets to be held and used, such as PP&E, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. Depreciation is computed on a straight-line basis, based on estimated useful lives of 10 to 25 years for buildings and improvements; 3 to 10 years for machinery and equipment; and 3 to 7 years for office equipment and furniture. Impairment of long-lived assets Long-lived assets or asset groups, including definite-lived intangible assets ("intangible assets") subject to amortization and property and equipment, are reviewed for impairment whenever events or changes in circumstances such as asset utilization, physical change, legal factors or other matters indicate that the carrying value of those assets may not be recoverable. When this review indicates the carrying value of an asset or asset group exceeds the sum of the undiscounted cash flows expected to result from the use and eventual disposition of the asset or asset group, an asset impairment expense is recognized in earnings in the period such a determination is made. The amount of the impairment expense recorded is the amount by which the carrying value of the impaired asset or asset group exceeds its fair value based on discounted cash flows. Goodwill and intangible assets Goodwill Goodwill represents the excess of the cost over the net tangible and identified intangible assets of acquired businesses. We have historically evaluated goodwill for impairment annually at our year-end, or more frequently if events or changes in circumstances indicate the carrying value of the goodwill may not be recoverable. In the third quarter of fiscal 2021, we changed the date of our annual goodwill impairment testing from our fiscal year-end to the first day in our fiscal fourth quarter. This change results in better alignment of the annual impairment test with our strategic and annual planning processes. This change was determined to not be material to and had no impact on our current or historical consolidated financial statements. Evaluating goodwill for impairment involves the determination of the fair value of each reporting unit in which goodwill is recorded using a qualitative or quantitative analysis. A reporting unit is an operating segment or a component of an operating segment for which discrete financial information is available and reviewed by segment management on a regular basis. During the third quarter of fiscal 2021, we combined two reporting units into one reporting unit, following certain structural and leadership changes at the Company, specifically within the Architectural Framing Systems segment. Within this segment, as a result of integration efforts that are ongoing, leadership over the Tubelite and Alumicor reporting units has been combined and functional leaders in areas such as operations, sales, marketing and administration are responsible for allocating resources and reviewing results of the combined business. The goodwill of the individual reporting units was therefore aggregated to the combined reporting unit. We evaluated goodwill on a qualitative basis prior to and subsequent to this change and concluded that no adjustment to the carrying value of goodwill was necessary as a result of this change. In addition, no qualitative indicators of impairment were identified during the third quarter of fiscal 2021, and therefore, no interim quantitative goodwill impairment evaluation was performed. Following this change, we have eight reporting units, six of which have goodwill. If the fair value of a reporting unit exceeds the carrying value, goodwill impairment is not indicated. If the carrying amount of a reporting unit is determined to be higher than its estimated fair value, the excess is recognized as an impairment expense. We estimate the fair value of a reporting unit using both the income approach and the market approach. The income approach uses a discounted cash flow methodology that involves significant judgment and projections of future performance. Assumptions about future revenues and future operating expenses, capital expenditures and changes in working capital are based on the annual operating plan and other business plans for each reporting unit. These plans take into consideration numerous factors, including historical experience, current and future operational plans, anticipated future economic conditions and growth expectations for the industries and end markets in which we participate. These projections are discounted using a weighted-average cost of capital, which considers the risk inherent in our projections of future cash flows. We determine the weighted-average cost of capital for this analysis by weighting the required returns on interest bearing debt and common equity capital in proportion to their estimated percentages in an expected capital structure, using published data where possible. We used discount rates that are commensurate with the risks and uncertainties inherent in the respective businesses and in the internally developed forecasts. The market approach uses a multiple of earnings and revenue based on guidelines for publicly traded companies. Intangible assets We have intangible assets for certain acquired trade names and trademarks which are determined to have indefinite useful lives. We test indefinite-lived intangible assets for impairment annually at the same measurement date as goodwill, the first day of our fiscal fourth quarter, or more frequently if events or changes in circumstances indicate that it is more likely than not that the asset is impaired. If the carrying amount of an indefinite-lived intangible asset exceeds its fair value, an impairment expense is recognized in an amount equal to that excess. If an impairment expense is recognized, the adjusted carrying amount becomes the asset's new accounting basis. Fair value of indefinite-lived intangible assets is measured using the relief-from-royalty method. This method assumes the trade name or trademark has value to the extent that the owner is relieved of the obligation to pay royalties for the benefits received from the asset. This method requires estimation of future revenue from the related asset, the appropriate royalty rate, and the weighted average cost of capital. The assessment of fair value involves significant judgment and projections about future performance. Definite-lived intangible assets are amortized based on estimated useful lives ranging from 18 months to 30 years and are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. The estimated useful lives of all intangible assets are reviewed annually, and we have determined that the remaining lives were appropriate. Leases On March 3, 2019, we adopted ASU 2016-02, Leases, which results in recognizing a right-of-use asset and lease liability on our consolidated balance sheet at lease commencement for leases with terms greater than twelve months. The initial lease liability is recognized at the present value of remaining lease payments over the lease term. Leases with an initial term of twelve months or less are not recorded on our consolidated balance sheet. We recognize lease expense for operating leases on a straight-line basis over the lease term. We combine lease and non-lease components, such as common area maintenance costs, in calculating the related asset and lease liabilities for all underlying asset groups. Refer to additional information in Note 8. Self-Insurance We obtain commercial insurance to provide coverage for potential losses in areas such as employment practices, workers' compensation, directors and officers, automobile, architect's and engineer's errors and omissions, product rework and general liability. A substantial portion of this risk is retained on a self-insured basis through our wholly-owned insurance subsidiary. We establish a reserve for estimated ultimate losses on reported claims and those incurred but not yet reported utilizing actuarial projections. Reserves are classified within other current liabilities or long-term self-insurance reserves based on expectations of when the estimated loss will be paid. Additionally, we maintain a self-insurance reserve for health insurance programs offered to eligible employees, included within accrued self-insurance reserves. The reserve includes an estimate for losses on reported claims as well as for amounts incurred but not yet reported, based on historical trends. Warranty and project-related contingencies We are subject to claims associated with our products and services, principally as a result of disputes with our customers involving the performance or aesthetics of our architectural products and services. We reserve estimated exposures on known claims, as well as on a portion of anticipated claims for product warranty and rework costs, based on historical product liability claims as a ratio of sales. We also reserve for estimated exposures on other claims as they are known and reasonably estimable. Reserves are included in other current and non-current liabilities based on the estimated timing of dispute resolution. Foreign currency Local currencies are considered the functional currencies for our subsidiaries outside of the United States. Assets and liabilities of these subsidiaries are translated at the exchange rates at the balance sheet date. Income and expense items are translated using average monthly exchange rates. Translation adjustments are included in accumulated other comprehensive loss in the consolidated balance sheets. Derivatives and hedging activities We are exposed to, among other risks, the impact of changes in aluminum prices, foreign currency exchange rates, and interest rates in the normal course of business. In order to manage the exposure and volatility arising from these risks, we utilize derivative financial instruments to offset a portion of these risks. We use derivative financial instruments only to the extent necessary to hedge identified business risks, and do not hold or issue derivative financial instruments for trading purposes and are not a party to leveraged derivatives. All derivative instruments within the scope of ASC 815, Derivatives and Hedging, are recorded as either assets or liabilities at fair value on the consolidated balance sheets. All hedging instruments that qualify for hedge accounting are designated and effective as hedges with changes recognized in other comprehensive earnings (loss). Instruments that do not qualify for hedge accounting are marked to market with changes recognized in current earnings. Cash flows from derivative instruments are classified in the statements of cash flows in the same category as the cash flows from the items subject to designated hedge or undesignated (economic) hedge relationships. Please refer to Note 4 for further disclosure on derivatives. Revenue recognition On March 4, 2018, we adopted ASC 606, Revenue from Contracts with Customers, and as a result, made updates to our significant accounting policy for revenue recognition. We generate revenue from the design, engineering and fabrication of architectural glass, curtainwall, window, storefront and entrance systems, and from installing those products on commercial buildings. We also manufacture value-added glass and acrylic products. Due to the diverse nature of our operations and various types of contracts with customers, we have businesses that recognize revenue over time and businesses that recognize revenue at a point in time. During fiscal 2021, approximately 41 percent of our total revenue is recognized at the time products are shipped from our manufacturing facilities, which is when control is transferred to our customer, consistent with past practices. These businesses do not generate contract-related assets or liabilities. Variable consideration associated with these contracts and orders, generally related to early pay discounts or volume rebates, is not considered significant. We also have three businesses which operate under long-term, fixed-price contracts, representing approximately 36 percent of our total revenue in the current year. The contracts for these businesses have a single, bundled performance obligation, as these businesses generally provide interrelated products and services and integrate these products and services into a combined output specified by the customer. The customer obtains control of this combined output, generally integrated window systems or installed window and curtainwall systems, over time. We measure progress on these contracts following an input method, by comparing total costs incurred to-date to the total estimated costs for the contract, and record that proportion of the total contract price as revenue in the period. Contract costs include materials, labor and other direct costs related to contract performance. We believe this method of recognizing revenue is consistent with our progress in satisfying our contract obligations. Due to the nature of the work required under these long-term contracts, the estimation of total revenue and costs incurred throughout a project is subject to many variables and requires significant judgment. It is common for these contracts to contain potential bonuses or penalties which are generally awarded or charged upon certain project milestones or cost or timing targets, and these can be based on customer discretion. We estimate variable consideration at the most likely amount to which we expect to be entitled. We include estimated amounts in the transaction price to the extent that it is probable that a significant reversal of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is resolved. Our estimates of variable consideration and determination of whether to include estimated amounts in the transaction price are based largely on our assessments of anticipated performance and all information (historical, current and forecasted) that is reasonably available to us. Long-term contracts are often modified to account for changes in contract specifications and requirements of work to be performed. We consider contract modifications to exist when the modification, generally through a change order, either creates new or changes existing enforceable rights and obligations, and we evaluate these types of modifications to determine whether they may be considered distinct performance obligations. In most cases, these contract modifications are for goods or services that are not distinct from the existing contract, due to the significant integration service provided in the context of the contract. Therefore, these modifications are accounted for as part of the existing contract. The effect of a contract modification on the transaction price and our measure of progress is recognized as an adjustment to revenue, generally on a cumulative catch-up basis. Typically, under these fixed-price contracts, we bill our customers following an agreed-upon schedule based on work performed. Because the progress billings do not generally correspond to our measurement of revenue on a contract, we generate contract assets when we have recognized revenue in excess of the amount billed to the customer. We generate contract liabilities when we have billed the customer in excess of revenue recognized on a contract. Finally, we have one business, making up approximately 23 percent of our total revenue in the current year, that recognizes revenue following an over-time output method based upon units produced. The customer is considered to have control over the products at the time of production, as the products are highly customized with no alternative use, and we have an enforceable right to payment for performance completed over the production period. We believe this over-time output method of recognizing revenue reasonably depicts the fulfillment of our performance obligations under our contracts. Billings still occur upon shipment. Therefore, contract assets are generated for the unbilled amounts on contracts when production is complete. Variable consideration associated with these orders, generally related to early pay discounts, is not considered significant. Additionally, we have made the following policy elections associated with revenue recognition: •We account for shipping and handling activities that occur after control of the related goods transfers to the customer as fulfillment activities, instead of assessing such activities as performance obligations. •We exclude from the transaction price all sales taxes related to revenue-producing transactions that are collected from the customer for a government authority. We are considered a pass-through conduit for collecting and remitting sales taxes. •We generally expense incremental costs of obtaining a contract when incurred because the amortization period would be less than one year. These costs primarily relate to sales commissions and are included in selling, general and administrative expenses. •We do not adjust contract price for a significant financing component, as we expect the period between when our goods and services are transferred to the customer and when the customer pays for those goods and services to be less than a year. Shipping and handling Amounts billed to a customer in a sales transaction related to shipping and handling are reported as revenue. Costs we incur for shipping and handling are reported as cost of sales. Research and development Research and development costs are expensed as incurred and were $15.3 million, $16.6 million and $19.5 million for fiscal 2021, 2020 and 2019, respectively. Of these amounts, $9.9 million, $8.0 million and $6.5 million, respectively, were focused primarily upon design of custom window and curtainwall systems in accordance with customer specifications and are included in cost of sales. The remainder of the expense is included within selling, general and administrative expenses. Advertising Advertising costs are expensed as incurred within selling, general and administrative expenses, and were $1.1 million in fiscal 2021, $1.4 million in fiscal 2020 and $1.5 million in fiscal 2019. Income taxes The Company recognizes deferred tax assets and liabilities based upon the future tax consequences of temporary differences between financial statement carrying amounts of assets and liabilities and their respective tax bases. See Note 13 for additional information regarding income taxes. Subsequent events We have evaluated subsequent events for potential recognition and disclosure through the date of this filing. Subsequent to the end of the year, we purchased 173,000 shares of stock under our authorized share repurchase program, at a total cost of $6.2 million. Adoption of new accounting standards In June 2016, the FASB issued ASU 2016-13, Measurement of Credit Losses on Financial Instruments, which revises guidance for the accounting for credit losses on financial instruments within its scope. The new standard introduces an approach, based on expected losses, to estimate credit losses on certain types of financial instruments, including accounts receivable, and modifies the impairment model for available-for-sale debt securities. We adopted this standard at the beginning of fiscal 2021, following the modified retrospective application approach. Additionally, the new guidance makes targeted improvements to the impairment model for certain available-for-sale debt securities, including eliminating the concept of "other than temporary" from that model. The portion of the guidance related to available-for-sale debt securities was adopted following a prospective approach. The adoption of this ASU did not have a significant impact on earnings or financial condition. Refer to additional disclosures in Notes 2 and 4. Accounting standards not yet adopted In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. The amendments in this ASU removed exceptions on intraperiod tax allocations and reporting and provided simplification on accounting for franchise taxes, tax basis goodwill and tax law changes. We are evaluating the expected impact these amendments will have on our consolidated financial statements, but the impact is not expected to be significant. In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting. The amendments in this ASU provide optional guidance for a limited period of time to ease the potential burden in accounting for (or recognizing the effects of) reference rate reform on financial reporting. The amendments in this ASU provide optional expedients and exceptions for applying U.S. GAAP to contracts, hedging relationships, and other transactions affected by reference rate reform if certain criteria are met. The amendments in this ASU apply only to contracts, hedging relationships, and other transactions that reference LIBOR or another reference rate expected to be discontinued because of reference rate reform. We are evaluating the expected impact these amendments and reference rate reform will have on our consolidated financial statements and various contracts but the impact is not expected to be significant.

The consolidated financial statements include the balances of Apogee Enterprises, Inc. and its subsidiaries (Apogee, we, us, our or the Company) after elimination of intercompany balances and transactions. We consolidate variable interest entities related to our New Market Tax Credit transactions as it has been determined that the Company is the primary beneficiary of those entities' operations (refer to Note 10 for more information).

To the extent the amortized cost basis of the available-for-sale securities exceeds the fair value, the Company assesses the debt securities for credit loss. When assessing the risk of credit loss, the Company considers factors such as the severity and the reason of the decline in value, such as any changes to the rating of the security by a rating agency or other adverse conditions specifically related to the security, and management's intended holding period and time horizon for selling. During fiscal 2021, 2020, and 2019, the Company did not recognize any credit losses related to its available-for-sale securities. Further, as of February 27, 2021 and February 29, 2020, the Company did not record an allowance for credit losses related to its available-for-sale securities. Marketable securities are included in other current and non-current assets on the consolidated balance sheets and gross realized gains and losses are included in other income (expense), net in our consolidated results of operations.

Property, plant and equipment (PP&E) is recorded at cost. Significant improvements and renewals that extend the useful life of the asset are capitalized. Repairs and maintenance are charged to expense as incurred. When an asset is retired or otherwise disposed of, the cost and related accumulated depreciation are removed from the accounts and any related gains or losses are included in selling, general and administrative expenses. Long-lived assets to be held and used, such as PP&E, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount may not be recoverable.

Long-lived assets or asset groups, including definite-lived intangible assets ("intangible assets") subject to amortization and property and equipment, are reviewed for impairment whenever events or changes in circumstances such as asset utilization, physical change, legal factors or other matters indicate that the carrying value of those assets may not be recoverable. When this review indicates the carrying value of an asset or asset group exceeds the sum of the undiscounted cash flows expected to result from the use and eventual disposition of the asset or asset group, an asset impairment expense is recognized in earnings in the

Goodwill represents the excess of the cost over the net tangible and identified intangible assets of acquired businesses. We have historically evaluated goodwill for impairment annually at our year-end, or more frequently if events or changes in circumstances indicate the carrying value of the goodwill may not be recoverable. In the third quarter of fiscal 2021, we changed the date of our annual goodwill impairment testing from our fiscal year-end to the first day in our fiscal fourth quarter. This change results in better alignment of the annual impairment test with our strategic and annual planning processes. This change was determined to not be material to and had no impact on our current or historical consolidated financial statements.

Evaluating goodwill for impairment involves the determination of the fair value of each reporting unit in which goodwill is recorded using a qualitative or quantitative analysis. A reporting unit is an operating segment or a component of an operating segment for which discrete financial information is available and reviewed by segment management on a regular basis. During the third quarter of fiscal 2021, we combined two reporting units into one reporting unit, following certain structural and leadership changes at the Company, specifically within the Architectural Framing Systems segment. Within this segment, as a result of integration efforts that are ongoing, leadership over the Tubelite and Alumicor reporting units has been combined and functional leaders in areas such as operations, sales, marketing and administration are responsible for allocating resources and reviewing results of the combined business. The goodwill of the individual reporting units was therefore aggregated to the combined reporting unit. We evaluated goodwill on a qualitative basis prior to and subsequent to this change and concluded that no adjustment to the carrying value of goodwill was necessary as a result of this change. In addition, no qualitative indicators of impairment were identified during the third quarter of fiscal 2021, and therefore, no interim quantitative goodwill impairment evaluation was performed. Following this change, we have eight reporting units, six of which have goodwill. If the fair value of a reporting unit exceeds the carrying value, goodwill impairment is not indicated. If the carrying amount of a reporting unit is determined to be higher than its estimated fair value, the excess is recognized as an impairment expense.

We estimate the fair value of a reporting unit using both the income approach and the market approach. The income approach uses a discounted cash flow methodology that involves significant judgment and projections of future performance. Assumptions about future revenues and future operating expenses, capital expenditures and changes in working capital are based on the annual operating plan and other business plans for each reporting unit. These plans take into consideration numerous factors, including historical experience, current and future operational plans, anticipated future economic conditions and growth expectations for the industries and end markets in which we participate. These projections are discounted using a weighted-average cost of capital, which considers the risk inherent in our projections of future cash flows. We determine the weighted-average cost of capital for this analysis by weighting the required returns on interest bearing debt and common equity capital in proportion to their estimated percentages in an expected capital structure, using published data where possible. We used discount rates that are commensurate with the risks and uncertainties inherent in the respective businesses and in the internally developed forecasts. The market approach uses a multiple of earnings and revenue based on guidelines for publicly traded companies.

We have intangible assets for certain acquired trade names and trademarks which are determined to have indefinite useful lives. We test indefinite-lived intangible assets for impairment annually at the same measurement date as goodwill, the first day of our fiscal fourth quarter, or more frequently if events or changes in circumstances indicate that it is more likely than not that the asset is impaired. If the carrying amount of an indefinite-lived intangible asset exceeds its fair value, an impairment expense is recognized in an amount equal to that excess. If an impairment expense is recognized, the adjusted carrying amount becomes the asset's new accounting basis.

Fair value of indefinite-lived intangible assets is measured using the relief-from-royalty method. This method assumes the trade name or trademark has value to the extent that the owner is relieved of the obligation to pay royalties for the benefits received from the asset. This method requires estimation of future revenue from the related asset, the appropriate royalty rate, and the weighted average cost of capital. The assessment of fair value involves significant judgment and projections about future performance.

On March 3, 2019, we adopted ASU 2016-02, Leases, which results in recognizing a right-of-use asset and lease liability on our consolidated balance sheet at lease commencement for leases with terms greater than twelve months. The initial lease liability is recognized at the present value of remaining lease payments over the lease term. Leases with an initial term of twelve months or less are not recorded on our consolidated balance sheet. We recognize lease expense for operating leases on a straight-line basis over the lease term. We combine lease and non-lease components, such as common area maintenance costs, in calculating the related asset and lease liabilities for all underlying asset groups. Refer to additional information in Note 8.

We obtain commercial insurance to provide coverage for potential losses in areas such as employment practices, workers' compensation, directors and officers, automobile, architect's and engineer's errors and omissions, product rework and general liability. A substantial portion of this risk is retained on a self-insured basis through our wholly-owned insurance subsidiary. We establish a reserve for estimated ultimate losses on reported claims and those incurred but not yet reported utilizing actuarial projections. Reserves are classified within other current liabilities or long-term self-insurance reserves based on expectations of when the estimated loss will be paid.

We are subject to claims associated with our products and services, principally as a result of disputes with our customers involving the performance or aesthetics of our architectural products and services. We reserve estimated exposures on known claims, as well as on a portion of anticipated claims for product warranty and rework costs, based on historical product liability claims as a ratio of sales. We also reserve for estimated exposures on other claims as they are known and reasonably estimable. Reserves are included in other current and non-current liabilities based on the estimated timing of dispute resolution.

Local currencies are considered the functional currencies for our subsidiaries outside of the United States. Assets and liabilities of these subsidiaries are translated at the exchange rates at the balance sheet date. Income and expense items are translated using average monthly exchange rates. Translation adjustments are included in accumulated other comprehensive loss in the consolidated balance sheets.

We are exposed to, among other risks, the impact of changes in aluminum prices, foreign currency exchange rates, and interest rates in the normal course of business. In order to manage the exposure and volatility arising from these risks, we utilize derivative financial instruments to offset a portion of these risks. We use derivative financial instruments only to the extent necessary to hedge identified business risks, and do not hold or issue derivative financial instruments for trading purposes and are not a party to leveraged derivatives.

All derivative instruments within the scope of ASC 815, Derivatives and Hedging, are recorded as either assets or liabilities at fair value on the consolidated balance sheets. All hedging instruments that qualify for hedge accounting are designated and effective as hedges with changes recognized in other comprehensive earnings (loss). Instruments that do not qualify for hedge accounting are marked to market with changes recognized in current earnings. Cash flows from derivative instruments are classified in the statements of cash flows in the same category as the cash flows from the items subject to designated hedge or undesignated (economic) hedge relationships. Please refer to Note 4 for further disclosure on derivatives.

On March 4, 2018, we adopted ASC 606, Revenue from Contracts with Customers, and as a result, made updates to our significant accounting policy for revenue recognition. We generate revenue from the design, engineering and fabrication of architectural glass, curtainwall, window, storefront and entrance systems, and from installing those products on commercial buildings. We also manufacture value-added glass and acrylic products. Due to the diverse nature of our operations and various types of contracts with customers, we have businesses that recognize revenue over time and businesses that recognize revenue at a point in time.

We also have three businesses which operate under long-term, fixed-price contracts, representing approximately 36 percent of our total revenue in the current year. The contracts for these businesses have a single, bundled performance obligation, as these businesses generally provide interrelated products and services and integrate these products and services into a combined output specified by the customer. The customer obtains control of this combined output, generally integrated window systems or installed window and curtainwall systems, over time. We measure progress on these contracts following an input method, by comparing total costs incurred to-date to the total estimated costs for the contract, and record that proportion of the total contract price as revenue in the period. Contract costs include materials, labor and other direct costs related to contract performance. We believe this method of recognizing revenue is consistent with our progress in satisfying our contract obligations.

Due to the nature of the work required under these long-term contracts, the estimation of total revenue and costs incurred throughout a project is subject to many variables and requires significant judgment. It is common for these contracts to contain potential bonuses or penalties which are generally awarded or charged upon certain project milestones or cost or timing targets, and these can be based on customer discretion. We estimate variable consideration at the most likely amount to which we expect to be entitled. We include estimated amounts in the transaction price to the extent that it is probable that a significant reversal of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is resolved. Our estimates of variable consideration and determination of whether to include estimated amounts in the transaction price are based largely on our assessments of anticipated performance and all information (historical, current and forecasted) that is reasonably available to us.

Long-term contracts are often modified to account for changes in contract specifications and requirements of work to be performed. We consider contract modifications to exist when the modification, generally through a change order, either creates new or changes existing enforceable rights and obligations, and we evaluate these types of modifications to determine whether they may be considered distinct performance obligations. In most cases, these contract modifications are for goods or services that are not distinct from the existing contract, due to the significant integration service provided in the context of the contract. Therefore, these modifications are accounted for as part of the existing contract. The effect of a contract modification on the transaction price and our measure of progress is recognized as an adjustment to revenue, generally on a cumulative catch-up basis.

Typically, under these fixed-price contracts, we bill our customers following an agreed-upon schedule based on work performed. Because the progress billings do not generally correspond to our measurement of revenue on a contract, we generate contract assets when we have recognized revenue in excess of the amount billed to the customer. We generate contract liabilities when we have billed the customer in excess of revenue recognized on a contract.

Finally, we have one business, making up approximately 23 percent of our total revenue in the current year, that recognizes revenue following an over-time output method based upon units produced. The customer is considered to have control over the products at the time of production, as the products are highly customized with no alternative use, and we have an enforceable right to payment for performance completed over the production period. We believe this over-time output method of recognizing revenue reasonably depicts the fulfillment of our performance obligations under our contracts. Billings still occur upon shipment. Therefore, contract assets are generated for the unbilled amounts on contracts when production is complete. Variable consideration associated with these orders, generally related to early pay discounts, is not considered significant.

Research and development costs are expensed as incurred and were $15.3 million, $16.6 million and $19.5 million for fiscal 2021, 2020 and 2019, respectively. Of these amounts, $9.9 million, $8.0 million and $6.5 million, respectively, were focused primarily upon design of custom window and curtainwall systems in accordance with customer specifications and are included in cost of sales. The remainder of the expense is included within selling, general and administrative expenses.

In June 2016, the FASB issued ASU 2016-13, Measurement of Credit Losses on Financial Instruments, which revises guidance for the accounting for credit losses on financial instruments within its scope. The new standard introduces an approach, based on expected losses, to estimate credit losses on certain types of financial instruments, including accounts receivable, and modifies the impairment model for available-for-sale debt securities.

We adopted this standard at the beginning of fiscal 2021, following the modified retrospective application approach. Additionally, the new guidance makes targeted improvements to the impairment model for certain available-for-sale debt securities, including eliminating the concept of "other than temporary" from that model. The portion of the guidance related to available-for-sale debt securities was adopted following a prospective approach. The adoption of this ASU did not have a significant impact on earnings or financial condition. Refer to additional disclosures in Notes 2 and 4.

In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. The amendments in this ASU removed exceptions on intraperiod tax allocations and reporting and provided simplification on accounting for franchise taxes, tax basis goodwill and tax law changes. We are evaluating the expected impact these amendments will have on our consolidated financial statements, but the impact is not expected to be significant.

In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting. The amendments in this ASU provide optional guidance for a limited period of time to ease the potential burden in accounting for (or recognizing the effects of) reference rate reform on financial reporting. The amendments in this ASU provide optional expedients and exceptions for applying U.S. GAAP to contracts, hedging relationships, and other transactions affected by reference rate reform if certain criteria are met. The amendments in this ASU apply only to contracts, hedging relationships, and other transactions that reference LIBOR or another reference rate expected to be discontinued because of reference rate reform. We are evaluating the expected impact these amendments and reference rate reform will have on our consolidated financial statements and various contracts but the impact is not expected to be significant.