Summary of Significant Accounting Policies (Policies)	12 Months Ended
May. 31, 2015
Consolidation	Consolidation: The consolidated financial statements include the accounts of Worthington Industries, Inc. and consolidated subsidiaries (collectively, “we,” “our,” “Worthington,” or the “Company”). Investments in unconsolidated affiliates are accounted for using the equity method. Significant intercompany accounts and transactions are eliminated. dHybrid Systems, LLC (“dHybrid”), Spartan Steel Coating, LLC (“Spartan”), TWB Company, L.L.C. (“TWB”), Worthington Aritaş Basinçli Kaplar Sanayi (“Worthington Aritas”), Worthington Energy Innovations, LLC (“WEI”), and Worthington Nitin Cylinders Limited (“Worthington Nitin Cylinders”) in which we own controlling interests of 79.59%, 52%, 55%, 75%, 75%, and 60%, respectively, are consolidated with the equity owned by the other joint venture members shown as noncontrolling interests in our consolidated balance sheets, and the other joint venture members’ portions of net earnings and other comprehensive income shown as net earnings or comprehensive income attributable to noncontrolling interests in our consolidated statements of earnings and consolidated statements of comprehensive income, respectively.
Use of Estimates	Use of Estimates: The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States (“U.S. GAAP”) requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ from those estimates.
Cash and Cash Equivalents	Cash and Cash Equivalents: We consider all highly liquid investments purchased with an original maturity of three months or less to be cash equivalents.
Inventories	Inventories: Inventories are valued at the lower of cost or market. Cost is determined using the first-in, first-out method for all inventories. Due to the decline in steel prices, the replacement cost of our inventory was lower than what was reflected in our records at May 31, 2015. Accordingly, we recorded a lower of cost or market adjustment of $1,716,000 at May 31, 2015 to reflect this lower value. The entire amount related to our Steel Processing operating segment and was recorded in cost of goods sold. We believe our inventories were valued appropriately as of May 31, 2015 and May 31, 2014.
Derivative Financial Instruments	Derivative Financial Instruments: We utilize derivative financial instruments to manage exposure to certain risks related to our ongoing operations. The primary risks managed through the use of derivative instruments include interest rate risk, currency exchange risk and commodity price risk. All derivative instruments are accounted for using mark-to-market accounting. The accounting for changes in the fair value of a derivative instrument depends on whether it has been designated and qualifies as part of a hedging relationship and, if so, the reason for holding it. Gains and losses on fair value hedges are recognized in current period earnings in the same line as the underlying hedged item. The effective portion of gains and losses on cash flow hedges is deferred as a component of accumulated other comprehensive income or loss (“AOCI”) and recognized in earnings at the time the hedged item affects earnings, in the same financial statement caption as the underlying hedged item. Ineffectiveness of the hedges during the fiscal year ended May 31, 2015 (“fiscal 2015”), the fiscal year ended May 31, 2014 (“fiscal 2014”) and the fiscal year ended May 31, 2013 (“fiscal 2013”) was immaterial. Classification in the consolidated statements of earnings of gains and losses related to derivative instruments that do not qualify for hedge accounting is determined based on the underlying intent of the instruments. Cash flows related to derivative instruments are generally classified as operating activities in our consolidated statements of cash flows. In order for hedging relationships to qualify for hedge accounting under current accounting guidance, we formally document each hedging relationship and its risk management objective. This documentation includes the hedge strategy, the hedging instrument, the hedged item, the nature of the risk being hedged, how hedge effectiveness will be assessed prospectively and retrospectively as well as a description of the method used to measure hedge ineffectiveness. Derivative instruments are executed only with highly-rated financial institutions. No credit loss is anticipated on existing instruments, and no such material losses have been experienced to date. We monitor our positions, as well as the credit ratings of counterparties to those positions. We discontinue hedge accounting when it is determined that the derivative instrument is no longer effective in offsetting the hedged risk, expires or is sold, is terminated or is no longer designated as a hedging instrument because it is unlikely that a forecasted transaction will occur or we determine that designation of the hedging instrument is no longer appropriate. In all situations in which hedge accounting is discontinued and the derivative instrument is retained, we continue to carry the derivative instrument at its fair value on the consolidated balance sheet and recognize any subsequent changes in its fair value in net earnings immediately. When it is probable that a forecasted transaction will not occur, we discontinue hedge accounting and immediately recognize the gains and losses that were accumulated in AOCI. Refer to “Note P – Derivative Instruments and Hedging Activities” for additional information regarding the consolidated balance sheet location and the risk classification of our derivative instruments.
Risks and Uncertainties	Risks and Uncertainties: As of May 31, 2015, we, together with our unconsolidated affiliates, operated 83 manufacturing facilities in 26 states and 11 countries. A total of 33 of these facilities are operated by wholly-owned and consolidated subsidiaries of the Company. The remaining facilities are operated by our consolidated and unconsolidated joint ventures. As of May 31, 2015, we held equity positions in 13 active joint ventures, of which six are consolidated. Our largest market is the automotive market, which comprised 38% and 36% of consolidated net sales in fiscal 2015 and fiscal 2014, respectively. Our foreign operations represented 6% and 7% of consolidated net sales, (2)% of pre-tax earnings attributable to controlling interest, and 14% and 15% of consolidated net assets as of and for the years ended May 31, 2015 and 2014, respectively. As of May 31, 2015, approximately 6% of our consolidated labor force was represented by collective bargaining agreements. The concentration of credit risks from financial instruments related to the markets we serve is not expected to have a material adverse effect on our consolidated financial position, cash flows or future results of operations. In fiscal 2015, our largest customer accounted for approximately 7% of our consolidated net sales, and our ten largest customers accounted for approximately 29% of our consolidated net sales. A significant loss of, or decrease in, business from any of these customers could have an adverse effect on our sales and financial results if we cannot obtain replacement business. Also, due to consolidation within the industries we serve, including the construction, automotive and retail industries, our sales may be increasingly sensitive to deterioration in the financial condition of, or other adverse developments with respect to, one or more of our largest customers. Our principal raw material is flat-rolled steel, which we purchase from multiple primary steel producers. The steel industry as a whole has been cyclical, and at times availability and pricing can be volatile due to a number of factors beyond our control. This volatility can significantly affect our steel costs. In an environment of increasing prices for steel and other raw materials, in general, competitive conditions may impact how much of the price increases we can pass on to our customers. To the extent we are unable to pass on future price increases in our raw materials to our customers, our financial results could be adversely affected. Also, if steel prices decrease, in general, competitive conditions may impact how quickly we must reduce our prices to our customers and we could be forced to use higher-priced raw materials to complete orders for which the selling prices have decreased. Declining steel prices could also require us to write-down the value of our inventories to reflect current market pricing. Further, the number of suppliers has decreased in recent years due to industry consolidation and the financial difficulties of certain suppliers, and consolidation may continue. Accordingly, if delivery from a major steel supplier is disrupted, it may be more difficult to obtain an alternative supply than in the past.
Receivables	Receivables: We review our receivables on an ongoing basis to ensure that they are properly valued and collectible. This is accomplished through two contra-receivable accounts: returns and allowances and allowance for doubtful accounts. Returns and allowances, including limited warranties on certain products, are used to record estimates of returns or other allowances resulting from quality, delivery, discounts or other issues affecting the value of receivables. This account is estimated based on historical trends and current market conditions, with the offset to net sales. The returns and allowances account increased approximately $626,000 during fiscal 2015 to $6,393,000. The portion of the liability related to product warranties was immaterial at May 31, 2015 and May 31, 2014. The allowance for doubtful accounts is used to record the estimated risk of loss related to the customers’ inability to pay. This allowance is maintained at a level that we consider appropriate based on factors that affect collectability, such as the financial health of our customers, historical trends of charge-offs and recoveries and current economic and market conditions. As we monitor our receivables, we identify customers that may have payment problems, and we adjust the allowance accordingly, with the offset to selling, general and administrative (“SG&A”) expense. Account balances are charged off against the allowance when recovery is considered remote. The allowance for doubtful accounts increased approximately $42,000 during fiscal 2015 to $3,085,000. While we believe our allowances are adequate, changes in economic conditions, the financial health of customers and bankruptcy settlements could impact our future earnings. If the economic environment and market conditions deteriorate, particularly in the automotive and construction end markets where our exposure is greatest, additional reserves may be required.
Property and Depreciation	Property and Depreciation: Property, plant and equipment are carried at cost and depreciated using the straight-line method. Buildings and improvements are depreciated over 10 to 40 years and machinery and equipment over 3 to 20 years. Depreciation expense was $64,666,000, $62,344,000, and $56,002,000 during fiscal 2015, fiscal 2014 and fiscal 2013, respectively. Accelerated depreciation methods are used for income tax purposes.
Goodwill and Other Long-Lived Assets	Goodwill and Other Long-Lived Assets: We use the purchase method of accounting for all business combinations and recognize amortizable intangible assets separately from goodwill. The acquired assets and assumed liabilities in an acquisition are measured and recognized based on their estimated fair values at the date of acquisition, with goodwill representing the excess of the purchase price over the fair value of the identifiable net assets. A bargain purchase may occur, wherein the fair value of identifiable net assets exceeds the purchase price, and a gain is then recognized in the amount of that excess. Goodwill and intangible assets with indefinite lives are not amortized, but instead are tested for impairment annually, during the fourth quarter, or more frequently if events or changes in circumstances indicate that impairment may be present. Application of goodwill impairment testing involves judgment, including but not limited to, the identification of reporting units and estimation of the fair value of each reporting unit. A reporting unit is defined as an operating segment or one level below an operating segment. We test goodwill at the operating segment level as we have determined that the characteristics of the reporting units within each operating segment are similar and allow for their aggregation in accordance with the applicable accounting guidance. The goodwill impairment test consists of comparing the fair value of each operating segment, determined using discounted cash flows, to each operating segment’s respective carrying value. If the estimated fair value of an operating segment exceeds its carrying value, there is no impairment. If the carrying amount of the operating segment exceeds its estimated fair value, goodwill impairment is indicated. The amount of the impairment is determined by comparing the fair value of the net assets of the operating segment, excluding goodwill, to its estimated fair value, with the difference representing the implied fair value of the goodwill. If the implied fair value of the goodwill is lower than its carrying value, the difference is recorded as an impairment charge in our consolidated statements of earnings. The impairment test for indefinite-lived intangible assets consists of a comparison of the fair value of the intangible asset to its carrying value. If the carrying value of the intangible asset exceeds its fair value, the difference is recorded as an impairment charge in our consolidated statements of earnings. We review the carrying value of our long-lived assets, including intangible assets with finite useful lives, for impairment whenever events or changes in circumstances indicate that the carrying value of an asset or asset group may not be recoverable. Impairment testing involves a comparison of the sum of the undiscounted future cash flows of the asset or asset group to its respective carrying amount. If the sum of the undiscounted future cash flows exceeds the carrying amount, then no impairment exists. If the carrying amount exceeds the sum of the undiscounted future cash flows, then a second step is performed to determine the amount of impairment, if any, to be recognized. The loss recognized is equal to the amount that the carrying value of the asset or asset group exceeds fair value. Our impairment testing for both goodwill and other long-lived assets, including intangible assets with finite useful lives, is largely based on cash flow models that require significant judgment and require assumptions about future volume trends, revenue and expense growth rates; and, in addition, external factors such as changes in economic trends and cost of capital. Significant changes in any of these assumptions could impact the outcomes of the tests performed. See “Note C – Goodwill and Other Long-Lived Assets” for additional details regarding these assets and related impairment testing.
Leases	Leases: Certain lease agreements contain fluctuating or escalating payments and rent holiday periods. The related rent expense is recorded on a straight-line basis over the length of the lease term. Leasehold improvements made by the lessee, whether funded by the lessee or by landlord allowances or incentives, are recorded as leasehold improvement assets and will be amortized over the shorter of the economic life or the lease term. These incentives are also recorded as deferred rent and amortized as reductions in rent expense over the lease term.
Stock-Based Compensation	Stock-Based Compensation: At May 31, 2015, we had stock-based compensation plans for our employees as well as our non-employee directors as described more fully in “Note J – Stock-Based Compensation.” All share-based awards, including grants of stock options and restricted common shares, are recorded as expense in the consolidated statements of earnings based on their grant-date fair values.
Revenue Recognition	Revenue Recognition: We recognize revenue upon transfer of title and risk of loss, or in the case of toll processing revenue, upon delivery of the goods, provided evidence of an arrangement exists, pricing is fixed and determinable and the ability to collect is probable. We provide, through charges to net sales, for returns and allowances based on experience and current customer activities. We also provide, through charges to net sales, for customer rebates and sales discounts based on specific agreements and recent and anticipated levels of customer activity. In circumstances where the collection of payment is not probable at the time of shipment, we defer recognition of revenue until payment is collected.
Advertising Expense	Advertising Expense: We expense advertising costs as incurred. Advertising expense was $11,153,000, $6,788,000, and $6,179,000 for fiscal 2015, fiscal 2014, and fiscal 2013, respectively.
Shipping and Handling Fees and Costs	Shipping and Handling Fees and Costs: Shipping and handling fees billed to customers are included in net sales, and shipping and handling costs incurred are included in cost of goods sold.
Environmental Costs	Environmental Costs: Environmental costs are capitalized if the costs extend the life of the property, increase its capacity, and/or mitigate or prevent contamination from future operations. Costs related to environmental contamination treatment and clean up are charged to expense.
Income Taxes	Income Taxes: We account for income taxes using the asset and liability method. The asset and liability method requires the recognition of deferred tax assets and liabilities for expected future tax consequences of temporary differences that currently exist between the tax basis and the financial reporting basis of our assets and liabilities. In assessing the realizability of deferred tax assets, we consider whether it is more likely than not that all, or a portion, of the deferred tax assets will not be realized. We provide a valuation allowance for deferred income tax assets when it is more likely than not that a portion of such deferred income tax assets will not be realized. Tax benefits from uncertain tax positions that are recognized in the consolidated financial statements are measured based on the largest benefit that has a greater than fifty percent likelihood of being realized upon ultimate settlement. We have reserves for taxes and associated interest and penalties that may become payable in future years as a result of audits by taxing authorities. It is our policy to record these in income tax expense. While we believe the positions taken on previously filed tax returns are appropriate, we have established the tax and interest reserves in recognition that various taxing authorities may challenge our positions. The tax reserves are analyzed periodically, and adjustments are made as events occur to warrant adjustment to the reserves, such as lapsing of applicable statutes of limitations, conclusion of tax audits, additional exposure based on current calculations, identification of new issues and release of administrative guidance or court decisions affecting a particular tax issue.
Self-Insurance Reserves	Self-Insurance Reserves: We are largely self-insured with respect to workers’ compensation, general and automobile liability, property damage, employee medical claims and other potential losses. In order to reduce risk and better manage our overall loss exposure, we purchase stop-loss insurance that covers individual claims in excess of the deductible amounts. We maintain reserves for the estimated cost to settle open claims, which includes estimates of legal costs expected to be incurred, as well as an estimate of the cost of claims that have been incurred but not reported. These estimates are based on actuarial valuations that take into consideration the historical average claim volume, the average cost for settled claims, current trends in claim costs, changes in our business and workforce, general economic factors and other assumptions believed to be reasonable under the circumstances. The estimated reserves for these liabilities could be affected if future occurrences and claims differ from assumptions used and historical trends.
Recently Issued Accounting Standards	Recently Issued Accounting Standards: In May 2014, amended accounting guidance was issued that replaces most existing revenue recognition guidance under U.S. GAAP. The amended guidance requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. The amended guidance is effective for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period. Early application is not permitted. We are in the process of evaluating the effect this guidance will have on our consolidated financial position and results of operations. The amended guidance permits the use of either the retrospective or cumulative effect transition method. We have not selected a transition method nor have we determined the effect of the amended guidance on our ongoing financial reporting.
Economic (Non-designated) Hedges	Economic (Non-designated) Hedges We enter into foreign currency contracts to manage our foreign exchange exposure related to inter-company and financing transactions that do not meet the requirements for hedge accounting treatment. We also enter into certain commodity contracts that do not qualify for hedge accounting treatment. Accordingly, these derivative instruments are adjusted to current market value at the end of each period through earnings.
Cash Flow Hedges
Cash Flow Hedges	Cash Flow Hedges We enter into derivative instruments to hedge our exposure to changes in cash flows attributable to interest rate and commodity price fluctuations associated with certain forecasted transactions. These derivative instruments are designated and qualify as cash flow hedges. Accordingly, the effective portion of the gain or loss on the derivative instrument is reported as a component of other comprehensive income (“OCI”) and reclassified into earnings in the same line associated with the forecasted transaction and in the same period during which the hedged transaction affects earnings. The ineffective portion of the gain or loss on the derivative instrument is recognized in earnings immediately.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

May. 31, 2015

Consolidation: The consolidated financial statements include the accounts of Worthington Industries, Inc. and consolidated subsidiaries (collectively, “we,” “our,” “Worthington,” or the “Company”). Investments in unconsolidated affiliates are accounted for using the equity method. Significant intercompany accounts and transactions are eliminated.

dHybrid Systems, LLC (“dHybrid”), Spartan Steel Coating, LLC (“Spartan”), TWB Company, L.L.C. (“TWB”), Worthington Aritaş Basinçli Kaplar Sanayi (“Worthington Aritas”), Worthington Energy Innovations, LLC (“WEI”), and Worthington Nitin Cylinders Limited (“Worthington Nitin Cylinders”) in which we own controlling interests of 79.59%, 52%, 55%, 75%, 75%, and 60%, respectively, are consolidated with the equity owned by the other joint venture members shown as noncontrolling interests in our consolidated balance sheets, and the other joint venture members’ portions of net earnings and other comprehensive income shown as net earnings or comprehensive income attributable to noncontrolling interests in our consolidated statements of earnings and consolidated statements of comprehensive income, respectively.

Use of Estimates

Use of Estimates: The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States (“U.S. GAAP”) requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ from those estimates.

Cash and Cash Equivalents

Cash and Cash Equivalents: We consider all highly liquid investments purchased with an original maturity of three months or less to be cash equivalents.

Inventories

Inventories: Inventories are valued at the lower of cost or market. Cost is determined using the first-in, first-out method for all inventories. Due to the decline in steel prices, the replacement cost of our inventory was lower than what was reflected in our records at May 31, 2015. Accordingly, we recorded a lower of cost or market adjustment of $1,716,000 at May 31, 2015 to reflect this lower value. The entire amount related to our Steel Processing operating segment and was recorded in cost of goods sold. We believe our inventories were valued appropriately as of May 31, 2015 and May 31, 2014.

Derivative Financial Instruments

Derivative Financial Instruments: We utilize derivative financial instruments to manage exposure to certain risks related to our ongoing operations. The primary risks managed through the use of derivative instruments include interest rate risk, currency exchange risk and commodity price risk. All derivative instruments are accounted for using mark-to-market accounting. The accounting for changes in the fair value of a derivative instrument depends on whether it has been designated and qualifies as part of a hedging relationship and, if so, the reason for holding it. Gains and losses on fair value hedges are recognized in current period earnings in the same line as the underlying hedged item. The effective portion of gains and losses on cash flow hedges is deferred as a component of accumulated other comprehensive income or loss (“AOCI”) and recognized in earnings at the time the hedged item affects earnings, in the same financial statement caption as the underlying hedged item. Ineffectiveness of the hedges during the fiscal year ended May 31, 2015 (“fiscal 2015”), the fiscal year ended May 31, 2014 (“fiscal 2014”) and the fiscal year ended May 31, 2013 (“fiscal 2013”) was immaterial. Classification in the consolidated statements of earnings of gains and losses related to derivative instruments that do not qualify for hedge accounting is determined based on the underlying intent of the instruments. Cash flows related to derivative instruments are generally classified as operating activities in our consolidated statements of cash flows.

In order for hedging relationships to qualify for hedge accounting under current accounting guidance, we formally document each hedging relationship and its risk management objective. This documentation includes the hedge strategy, the hedging instrument, the hedged item, the nature of the risk being hedged, how hedge effectiveness will be assessed prospectively and retrospectively as well as a description of the method used to measure hedge ineffectiveness.

Derivative instruments are executed only with highly-rated financial institutions. No credit loss is anticipated on existing instruments, and no such material losses have been experienced to date. We monitor our positions, as well as the credit ratings of counterparties to those positions.

We discontinue hedge accounting when it is determined that the derivative instrument is no longer effective in offsetting the hedged risk, expires or is sold, is terminated or is no longer designated as a hedging instrument because it is unlikely that a forecasted transaction will occur or we determine that designation of the hedging instrument is no longer appropriate. In all situations in which hedge accounting is discontinued and the derivative instrument is retained, we continue to carry the derivative instrument at its fair value on the consolidated balance sheet and recognize any subsequent changes in its fair value in net earnings immediately. When it is probable that a forecasted transaction will not occur, we discontinue hedge accounting and immediately recognize the gains and losses that were accumulated in AOCI.

Refer to “Note P – Derivative Instruments and Hedging Activities” for additional information regarding the consolidated balance sheet location and the risk classification of our derivative instruments.

Risks and Uncertainties

Risks and Uncertainties: As of May 31, 2015, we, together with our unconsolidated affiliates, operated 83 manufacturing facilities in 26 states and 11 countries. A total of 33 of these facilities are operated by wholly-owned and consolidated subsidiaries of the Company. The remaining facilities are operated by our consolidated and unconsolidated joint ventures. As of May 31, 2015, we held equity positions in 13 active joint ventures, of which six are consolidated. Our largest market is the automotive market, which comprised 38% and 36% of consolidated net sales in fiscal 2015 and fiscal 2014, respectively. Our foreign operations represented 6% and 7% of consolidated net sales, (2)% of pre-tax earnings attributable to controlling interest, and 14% and 15% of consolidated net assets as of and for the years ended May 31, 2015 and 2014, respectively. As of May 31, 2015, approximately 6% of our consolidated labor force was represented by collective bargaining agreements. The concentration of credit risks from financial instruments related to the markets we serve is not expected to have a material adverse effect on our consolidated financial position, cash flows or future results of operations.

In fiscal 2015, our largest customer accounted for approximately 7% of our consolidated net sales, and our ten largest customers accounted for approximately 29% of our consolidated net sales. A significant loss of, or decrease in, business from any of these customers could have an adverse effect on our sales and financial results if we cannot obtain replacement business. Also, due to consolidation within the industries we serve, including the construction, automotive and retail industries, our sales may be increasingly sensitive to deterioration in the financial condition of, or other adverse developments with respect to, one or more of our largest customers.

Our principal raw material is flat-rolled steel, which we purchase from multiple primary steel producers. The steel industry as a whole has been cyclical, and at times availability and pricing can be volatile due to a number of factors beyond our control. This volatility can significantly affect our steel costs. In an environment of increasing prices for steel and other raw materials, in general, competitive conditions may impact how much of the price increases we can pass on to our customers. To the extent we are unable to pass on future price increases in our raw materials to our customers, our financial results could be adversely affected. Also, if steel prices decrease, in general, competitive conditions may impact how quickly we must reduce our prices to our customers and we could be forced to use higher-priced raw materials to complete orders for which the selling prices have decreased. Declining steel prices could also require us to write-down the value of our inventories to reflect current market pricing. Further, the number of suppliers has decreased in recent years due to industry consolidation and the financial difficulties of certain suppliers, and consolidation may continue. Accordingly, if delivery from a major steel supplier is disrupted, it may be more difficult to obtain an alternative supply than in the past.

Receivables

Receivables: We review our receivables on an ongoing basis to ensure that they are properly valued and collectible. This is accomplished through two contra-receivable accounts: returns and allowances and allowance for doubtful accounts. Returns and allowances, including limited warranties on certain products, are used to record estimates of returns or other allowances resulting from quality, delivery, discounts or other issues affecting the value of receivables. This account is estimated based on historical trends and current market conditions, with the offset to net sales. The returns and allowances account increased approximately $626,000 during fiscal 2015 to $6,393,000. The portion of the liability related to product warranties was immaterial at May 31, 2015 and May 31, 2014.

The allowance for doubtful accounts is used to record the estimated risk of loss related to the customers’ inability to pay. This allowance is maintained at a level that we consider appropriate based on factors that affect collectability, such as the financial health of our customers, historical trends of charge-offs and recoveries and current economic and market conditions. As we monitor our receivables, we identify customers that may have payment problems, and we adjust the allowance accordingly, with the offset to selling, general and administrative (“SG&A”) expense. Account balances are charged off against the allowance when recovery is considered remote. The allowance for doubtful accounts increased approximately $42,000 during fiscal 2015 to $3,085,000.

While we believe our allowances are adequate, changes in economic conditions, the financial health of customers and bankruptcy settlements could impact our future earnings. If the economic environment and market conditions deteriorate, particularly in the automotive and construction end markets where our exposure is greatest, additional reserves may be required.

Property and Depreciation

Property and Depreciation: Property, plant and equipment are carried at cost and depreciated using the straight-line method. Buildings and improvements are depreciated over 10 to 40 years and machinery and equipment over 3 to 20 years. Depreciation expense was $64,666,000, $62,344,000, and $56,002,000 during fiscal 2015, fiscal 2014 and fiscal 2013, respectively. Accelerated depreciation methods are used for income tax purposes.

Goodwill and Other Long-Lived Assets

Goodwill and Other Long-Lived Assets: We use the purchase method of accounting for all business combinations and recognize amortizable intangible assets separately from goodwill. The acquired assets and assumed liabilities in an acquisition are measured and recognized based on their estimated fair values at the date of acquisition, with goodwill representing the excess of the purchase price over the fair value of the identifiable net assets. A bargain purchase may occur, wherein the fair value of identifiable net assets exceeds the purchase price, and a gain is then recognized in the amount of that excess. Goodwill and intangible assets with indefinite lives are not amortized, but instead are tested for impairment annually, during the fourth quarter, or more frequently if events or changes in circumstances indicate that impairment may be present. Application of goodwill impairment testing involves judgment, including but not limited to, the identification of reporting units and estimation of the fair value of each reporting unit. A reporting unit is defined as an operating segment or one level below an operating segment. We test goodwill at the operating segment level as we have determined that the characteristics of the reporting units within each operating segment are similar and allow for their aggregation in accordance with the applicable accounting guidance.

The goodwill impairment test consists of comparing the fair value of each operating segment, determined using discounted cash flows, to each operating segment’s respective carrying value. If the estimated fair value of an operating segment exceeds its carrying value, there is no impairment. If the carrying amount of the operating segment exceeds its estimated fair value, goodwill impairment is indicated. The amount of the impairment is determined by comparing the fair value of the net assets of the operating segment, excluding goodwill, to its estimated fair value, with the difference representing the implied fair value of the goodwill. If the implied fair value of the goodwill is lower than its carrying value, the difference is recorded as an impairment charge in our consolidated statements of earnings. The impairment test for indefinite-lived intangible assets consists of a comparison of the fair value of the intangible asset to its carrying value. If the carrying value of the intangible asset exceeds its fair value, the difference is recorded as an impairment charge in our consolidated statements of earnings.

We review the carrying value of our long-lived assets, including intangible assets with finite useful lives, for impairment whenever events or changes in circumstances indicate that the carrying value of an asset or asset group may not be recoverable. Impairment testing involves a comparison of the sum of the undiscounted future cash flows of the asset or asset group to its respective carrying amount. If the sum of the undiscounted future cash flows exceeds the carrying amount, then no impairment exists. If the carrying amount exceeds the sum of the undiscounted future cash flows, then a second step is performed to determine the amount of impairment, if any, to be recognized. The loss recognized is equal to the amount that the carrying value of the asset or asset group exceeds fair value.

Our impairment testing for both goodwill and other long-lived assets, including intangible assets with finite useful lives, is largely based on cash flow models that require significant judgment and require assumptions about future volume trends, revenue and expense growth rates; and, in addition, external factors such as changes in economic trends and cost of capital. Significant changes in any of these assumptions could impact the outcomes of the tests performed. See “Note C – Goodwill and Other Long-Lived Assets” for additional details regarding these assets and related impairment testing.

Leases

Leases: Certain lease agreements contain fluctuating or escalating payments and rent holiday periods. The related rent expense is recorded on a straight-line basis over the length of the lease term. Leasehold improvements made by the lessee, whether funded by the lessee or by landlord allowances or incentives, are recorded as leasehold improvement assets and will be amortized over the shorter of the economic life or the lease term. These incentives are also recorded as deferred rent and amortized as reductions in rent expense over the lease term.

Stock-Based Compensation

Stock-Based Compensation: At May 31, 2015, we had stock-based compensation plans for our employees as well as our non-employee directors as described more fully in “Note J – Stock-Based Compensation.” All share-based awards, including grants of stock options and restricted common shares, are recorded as expense in the consolidated statements of earnings based on their grant-date fair values.

Revenue Recognition

Revenue Recognition: We recognize revenue upon transfer of title and risk of loss, or in the case of toll processing revenue, upon delivery of the goods, provided evidence of an arrangement exists, pricing is fixed and determinable and the ability to collect is probable. We provide, through charges to net sales, for returns and allowances based on experience and current customer activities. We also provide, through charges to net sales, for customer rebates and sales discounts based on specific agreements and recent and anticipated levels of customer activity. In circumstances where the collection of payment is not probable at the time of shipment, we defer recognition of revenue until payment is collected.

Advertising Expense

Advertising Expense: We expense advertising costs as incurred. Advertising expense was $11,153,000, $6,788,000, and $6,179,000 for fiscal 2015, fiscal 2014, and fiscal 2013, respectively.

Shipping and Handling Fees and Costs

Shipping and Handling Fees and Costs: Shipping and handling fees billed to customers are included in net sales, and shipping and handling costs incurred are included in cost of goods sold.

Environmental Costs

Environmental Costs: Environmental costs are capitalized if the costs extend the life of the property, increase its capacity, and/or mitigate or prevent contamination from future operations. Costs related to environmental contamination treatment and clean up are charged to expense.

Income Taxes

Income Taxes: We account for income taxes using the asset and liability method. The asset and liability method requires the recognition of deferred tax assets and liabilities for expected future tax consequences of temporary differences that currently exist between the tax basis and the financial reporting basis of our assets and liabilities. In assessing the realizability of deferred tax assets, we consider whether it is more likely than not that all, or a portion, of the deferred tax assets will not be realized. We provide a valuation allowance for deferred income tax assets when it is more likely than not that a portion of such deferred income tax assets will not be realized.

Tax benefits from uncertain tax positions that are recognized in the consolidated financial statements are measured based on the largest benefit that has a greater than fifty percent likelihood of being realized upon ultimate settlement.

We have reserves for taxes and associated interest and penalties that may become payable in future years as a result of audits by taxing authorities. It is our policy to record these in income tax expense. While we believe the positions taken on previously filed tax returns are appropriate, we have established the tax and interest reserves in recognition that various taxing authorities may challenge our positions. The tax reserves are analyzed periodically, and adjustments are made as events occur to warrant adjustment to the reserves, such as lapsing of applicable statutes of limitations, conclusion of tax audits, additional exposure based on current calculations, identification of new issues and release of administrative guidance or court decisions affecting a particular tax issue.

Self-Insurance Reserves

Self-Insurance Reserves: We are largely self-insured with respect to workers’ compensation, general and automobile liability, property damage, employee medical claims and other potential losses. In order to reduce risk and better manage our overall loss exposure, we purchase stop-loss insurance that covers individual claims in excess of the deductible amounts. We maintain reserves for the estimated cost to settle open claims, which includes estimates of legal costs expected to be incurred, as well as an estimate of the cost of claims that have been incurred but not reported. These estimates are based on actuarial valuations that take into consideration the historical average claim volume, the average cost for settled claims, current trends in claim costs, changes in our business and workforce, general economic factors and other assumptions believed to be reasonable under the circumstances. The estimated reserves for these liabilities could be affected if future occurrences and claims differ from assumptions used and historical trends.

Recently Issued Accounting Standards

Recently Issued Accounting Standards: In May 2014, amended accounting guidance was issued that replaces most existing revenue recognition guidance under U.S. GAAP. The amended guidance requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. The amended guidance is effective for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period. Early application is not permitted. We are in the process of evaluating the effect this guidance will have on our consolidated financial position and results of operations. The amended guidance permits the use of either the retrospective or cumulative effect transition method. We have not selected a transition method nor have we determined the effect of the amended guidance on our ongoing financial reporting.

Economic (Non-designated) Hedges

Economic (Non-designated) Hedges

We enter into foreign currency contracts to manage our foreign exchange exposure related to inter-company and financing transactions that do not meet the requirements for hedge accounting treatment. We also enter into certain commodity contracts that do not qualify for hedge accounting treatment. Accordingly, these derivative instruments are adjusted to current market value at the end of each period through earnings.

Cash Flow Hedges

Cash Flow Hedges

We enter into derivative instruments to hedge our exposure to changes in cash flows attributable to interest rate and commodity price fluctuations associated with certain forecasted transactions. These derivative instruments are designated and qualify as cash flow hedges. Accordingly, the effective portion of the gain or loss on the derivative instrument is reported as a component of other comprehensive income (“OCI”) and reclassified into earnings in the same line associated with the forecasted transaction and in the same period during which the hedged transaction affects earnings. The ineffective portion of the gain or loss on the derivative instrument is recognized in earnings immediately.