In August 2016, we entered into a definitive equity purchase agreement (the "Purchase Agreement") with Compañía de Petróleos de Chile COPEC S.A. and its subsidiary, Copec Inc., a Delaware corporation (collectively, "COPEC"). Under the terms of the Purchase Agreement, Delek agreed to sell, and COPEC agreed to purchase, 100% of the equity interests in Delek's wholly-owned subsidiaries MAPCO Express, Inc. ("MAPCO Express"), MAPCO Fleet, Inc., Delek Transportation, LLC, NTI Investments, LLC and GDK Bearpaw, LLC (collectively, the “Retail Entities”) for cash consideration of $535.0 million, subject to customary adjustments (the “ Retail Transaction”). The Retail Transaction closed in November 2016. As a result of the Purchase Agreement, we met the requirements under the provisions of Accounting Standards Codification ("ASC") 205-20, Presentation of Financial Statements - Discontinued Operations ("ASC 205-20") and ASC 360, Property, Plant and Equipment ("ASC 360"), to report the results of the Retail Entities as discontinued operations and to classify the Retail Entities as a group of assets held for sale. See Note 8 for further information regarding the Retail Entities.

During the third quarter 2017, we committed to a plan to sell certain assets associated with our Paramount and Long Beach, California refineries and Alon's California renewable fuels facility (collectively, the "California Discontinued Entities"), which were acquired as part of the Delek/Alon Merger. As a result of this decision and commitment to a plan, and because it was made within three months of the Delek/Alon Merger, we met the requirements under ASC 205-20 and ASC 360 to report the results of the California Discontinued Entities as discontinued operations and to classify the California Discontinued Entities as a group of assets held for sale. On March 16, 2018, Delek sold to World Energy, LLC (i) all of Delek’s membership interests in AltAir Paramount, LLC (Alon's California renewable fuels facility), (ii) certain refining assets and other related assets located in Paramount, California and (iii) certain associated tank farm and pipeline assets and other related assets located in California. The transaction to dispose of certain assets and liabilities associated with our Long Beach, California refinery, to Bridge Point Long Beach, LLC, closed July 17, 2018. See Note 8 for further information regarding the California Discontinued Entities.

On February 12, 2018, Delek announced it had reached a definitive agreement to sell certain assets and operations of four asphalt terminals (included in Delek's corporate/other segment), as well as an equity method investment in an additional asphalt terminal, to an affiliate of Andeavor. This transaction includes asphalt terminal assets in Bakersfield, Mojave and Elk Grove, California and Phoenix, Arizona, as well as Delek’s 50% equity interest in the Paramount-Nevada Asphalt Company, LLC joint venture that operates an asphalt terminal located in Fernley, Nevada. On May 21, 2018, Delek completed the transaction and received net proceeds of approximately $110.8 million, inclusive of the $75.0 million base proceeds as well as certain preliminary working capital adjustments. These associated assets did not meet the definition of held for sale pursuant to ASC 360 as of December 31, 2017, and therefore were not reflected as held for sale nor as discontinued operations in the consolidated financial statements as of and for the year ended December 31, 2017. See Note 8 for further information regarding the disposal of these assets held for sale.

As of December 31, 2017, our consolidated financial statements included the consolidated financial statements of the following variable interest entities: Delek Logistics Partners, LP ("Delek Logistics"), Alon USA Partners, LP (the "Alon Partnership") and AltAir Paramount LLC ("AltAir"). On February 7, 2018, Delek acquired the non-controlling interest in the Alon Partnership; and on March 16, 2018, we sold the membership interests

in AltAir. Thus, Delek Logistics is Delek's only remaining variable interest entity as of December 31, 2018. As the indirect owner of the general partner of Delek Logistics, we have the ability to direct the activities of this entity that most significantly impact economic performance. We are also considered to be the primary beneficiary for accounting purposes for this entity and are Delek Logistics' primary customer. As Delek Logistics does not derive an amount of gross margin material to us from third parties, there is limited risk to Delek associated with Delek Logistics' operations. However, in the event that Delek Logistics incurs a loss, our operating results will reflect such loss, net of intercompany eliminations, to the extent of our ownership interest in this entity.

The preparation of financial statements in conformity with U.S. generally accepted accounting principles ("GAAP") and in accordance with the rules and regulations of the Securities and Exchange Commission ("SEC") requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. In the opinion of management, all adjustments necessary for a fair presentation of the financial condition and the results of operations have been included. All significant intercompany transactions and account balances have been eliminated in consolidation. All adjustments are of a normal, recurring nature.

Certain prior period amounts have been reclassified in order to conform to the current year presentation. Additionally, certain changes to presentation of the prior period statements of income have been made in order to conform to the current period presentation, primarily relating to the addition of a subtotal entitled 'cost of sales' which includes all costs directly attributable to the generation of the related revenue, as defined by GAAP, and the retitling of what was previously referred to as 'cost of goods sold' to 'cost of materials and other'. In connection with this change in presentation, we have revised our related accounting policy for 'Cost of Materials and Other and Operating Expenses' presented below.

Our corporate activities, results of certain immaterial operating segments (including our asphalt terminal operations effective with the Delek/ Alon Merger), our non-controlling equity interest of approximately 47% of the outstanding shares in Alon (which was accounted for as an equity method investment) prior to the Delek/Alon Merger, results and assets of discontinued operations and intercompany eliminations are reported in corporate, other and eliminations segment. Decisions concerning the allocation of resources and assessment of operating performance are made based on this segmentation. Management measures the operating performance of each of the reportable segments based on the segment contribution margin.

Prior to the Delek/Alon Merger, the refining segment operated high conversion, independent refineries in Tyler, Texas (the "Tyler refinery") and El Dorado, Arkansas (the "El Dorado refinery") and biodiesel facilities in Cleburne, Texas and Crossett, Arkansas. Effective with the Delek/Alon Merger, the refining segment now also includes the operations of high conversion, independent refineries in Big Spring, Texas (the "Big Spring refinery"), Krotz Springs, Louisiana (the "Krotz Springs refinery") and in Bakersfield, California (the "Bakersfield refinery"). The Bakersfield refinery has not processed crude oil since 2012 due to the high cost of crude oil relative to product yield and low asphalt demand. The logistics segment owns and operates crude oil and refined products logistics and marketing assets. The retail segment markets gasoline, diesel and other refined petroleum products, and convenience merchandise through a network of company-operated retail fuel and convenience stores and includes the assets and results of operations of the retail business acquired in connection with the Delek/Alon Merger. The assets and results of operations related to the Retail Entities disposed in 2016 were classified as discontinued operations and therefore are excluded from our retail segment and included in our corporate, other and eliminations segment.

Delek maintains cash and cash equivalents in accounts with large, U.S. or multi-national financial institutions. All highly liquid investments purchased with a term of three months or less are considered to be cash equivalents. As of December 31, 2018 and 2017, these cash equivalents consisted primarily of bank money market accounts and bank certificates of deposit, as well as overnight investments in U.S. Government or its agencies' obligations and bank repurchase obligations collateralized by U.S. Government or its agencies' obligations.

Refinery crude oil, work-in-process, refined products, blendstocks and asphalt inventory for all of our operations, excluding the refinery located in Tyler, Texas (the "Tyler refinery") and merchandise inventory in our Retail segment, are stated at the lower of cost determined using the first-in, first-out (“FIFO”) basis or net realizable value. Cost of inventory at the Tyler refinery is determined using the last-in, first-out (“LIFO”) inventory valuation method and inventory is stated at the lower of LIFO cost or market. Retail merchandise inventory consists of cigarettes, beer, convenience merchandise and food service merchandise and is stated at estimated cost as determined by the retail inventory method. We are not subject to concentration risk with specific suppliers, since our crude oil and refined products inventory purchases are commodities that are readily available from a large selection of suppliers.

Commodity investments represent those commodities (generally crude oil) physically on hand as a result of trading activities with physical forward contracts where such crude will not be used (either directly in production or indirectly through inventory optimization) in the normal course of our refining business. Such investment stores are maintained on a weighted average cost basis for determining realized gains and losses on physical sales under forward contracts, and ending balances are adjusted to fair value at each reporting date using published market prices of the commodity on the applicable exchange. The commodity investments are included in other current assets on the accompanying consolidated balance sheets and changes in fair value are recorded in other operating income (expense) in the accompanying consolidated statements of income.

Assets acquired by Delek in conjunction with business acquisitions are recorded at estimated fair value at the acquisition date in accordance with the purchase method of accounting as prescribed in ASC 805, Business Combinations ("ASC 805"). Other acquisitions of property and equipment are carried at cost. Betterments, renewals and extraordinary repairs that extend the life of an asset are capitalized. Maintenance and repairs are charged to expense as incurred. Delek owns certain fixed assets on leased locations and depreciates these assets and asset improvements over the lesser of management's estimated useful lives of the assets or the remaining lease term.

Delek has intangible assets associated with third-party fuel supply agreements, fuel trade name, liquor licenses, refinery permits and below market leases resulting from to the Delek/Alon Merger, in addition to a long-term supply contract, capacity contracts, line space history and rights of way. We amortize the definite-lived intangible assets on straight-line bases over the estimated useful lives of five to 15 years. The amortization expense is included in depreciation and amortization on the accompanying consolidated statements of income.

Property, plant and equipment held and used and definite-life intangibles are evaluated for impairment whenever indicators of impairment exist. In accordance with ASC 360 and ASC 350, Intangibles - Goodwill and Other, Delek evaluates the realizability of these long-lived assets as events occur that might indicate potential impairment. In doing so, Delek assesses whether the carrying amount of the asset is recoverable by estimating the sum of the future cash flows expected to result from the asset, undiscounted and without interest charges. If the carrying amount is more than the recoverable amount, an impairment charge must be recognized based on the fair value of the asset. These impairment charges are included in other operating income in our consolidated statements of income. There were no impairment charges identified for the years ended December 31, 2018, 2017 or 2016 .

For equity investments that are not required to be consolidated under the variable or voting interest model, we evaluate the level of influence we are able to exercise over an entity’s operations to determine whether to use the equity method of accounting. Our judgment regarding the level of influence over an equity method investment includes considering key factors such as our ownership interest, participation in policy-making and other significant decisions and material intercompany transactions. Equity investments for which we determine we have significant influence are accounted for as equity method investments. Amounts recognized for equity method investments are included in equity method investments in our consolidated balance sheets and adjusted for our share of the net earnings and losses of the investee and cash distributions, which are separately stated in our consolidated statements of income and our consolidated statements of cash flows. We evaluate our equity method investments presented for impairment whenever events or changes in circumstances indicate that the carrying amounts of such investments may be impaired. We recorded an impairment charge of $245.3 million on our investment in Alon based on the quoted market price of our ALJ Shares as of September 30, 2016, during the year ended December 31, 2016. This impairment is reflected in the loss on impairment of equity method investment in our consolidated statements of income for the year ended December 31, 2016. There were no impairment losses recorded on equity method investments for the year ended December 31, 2018 or 2017. See Note 7 for further information on our equity method investments.

Refinery turnaround costs are incurred in connection with planned shutdowns and inspections of our refineries' major units to perform necessary repairs and replacements. Refinery turnaround costs are deferred when incurred, classified as property, plant and equipment and amortized on a straight-line basis over that period of time estimated to lapse until the next planned turnaround occurs. Refinery turnaround costs include, among other things, the cost to repair, restore, refurbish or replace refinery equipment such as vessels, tanks, reactors, piping, rotating equipment, instrumentation, electrical equipment, heat exchangers and fired heaters.

Goodwill in an acquisition represents the excess of the aggregate purchase price over the fair value of the identifiable net assets. Goodwill is reviewed at least annually for impairment, or more frequently if indicators of impairment exist, such as disruptions in our business, unexpected significant declines in operating results or a sustained market capitalization decline. Goodwill is evaluated for impairment by comparing the carrying amount of the reporting unit to its estimated fair value. Prior to the adoption of Accounting Standard Update ("ASU") 2017-04, Simplifying the Test for Goodwill Impairment, If a reporting unit's carrying amount exceeds its fair value (Step 1), the impairment assessment leads to the testing of the implied fair value of the reporting unit's goodwill to its carrying amount (Step 2). If the implied fair value is less than the carrying amount, a goodwill impairment charge is recorded. Subsequent to adoption of ASU 2017-04 (which we adopted during the fourth quarter of 2018, as permitted by the ASU), Step 2 is no longer required, but rather any impairment is determined based on the results of Step 1.

In assessing the recoverability of goodwill, assumptions are made with respect to future business conditions and estimated expected future cash flows to determine the fair value of a reporting unit. We may consider inputs such as a market participant weighted average cost of capital, estimated growth rates for revenue, gross profit and capital expenditures based on history and our best estimate of future forecasts, all of which are subject to significant judgment and estimates. We may also estimate the fair values of the reporting units using a multiple of expected future cash flows, such as those used by third-party analysts. If these estimates and assumptions change in the future, due to factors such as a decline in general economic conditions, competitive pressures on sales and margins and other economic and industry factors beyond management's control, an impairment charge may be required. A significant risk to our future results and the potential future impairment of goodwill is the volatility of the crude oil and the refined product markets which is often unpredictable and may negatively impact our results of operations in ways that cannot be anticipated and that are beyond management's control.

The U.S. Environmental Protection Agency (“EPA”) requires certain refiners to blend biofuels into the fuel products they produce pursuant to the EPA’s Renewable Fuel Standard - 2 ("RFS-2"). Alternatively, credits, called Renewable Identification Numbers ("RINs"), which may be generated and/or purchased, can be used to satisfy this obligation instead of physically blending biofuels ("RINs Obligation"). All of our refineries are obligated parties to the RFS-2 (see Note 14 for further discussion of these requirements). To the extent that any of our refineries is unable to blend biofuels at the required rate, it must purchase RINs in the open market to satisfy its annual requirement. Our RINs Obligation is based on the amount of RINs we must purchase and the price of those RINs as of the balance sheet date. The cost of RINs used each period is charged to cost of materials and other in the consolidated statements of income. We recognize a liability at the end of each reporting period in which we do not have sufficient RINs to cover the RINs Obligation. The liability is calculated by multiplying the RINs shortage (based on actual results) by the period end RIN spot price. From time to time, we may hold RINs generated or acquired in excess of our current obligations. We recognize an asset at the end of each reporting period in which we have generated or acquired RINs in excess of our RINs Obligation. The asset is calculated by multiplying the RINs surplus (based on actual results) by the period end RIN spot price. The value of RINs in excess of our RINs Obligation, if any, would be reflected in other current assets on the consolidated balance sheets. RINs generated in excess of our current RINs Obligation may be sold or held to offset future RINs Obligations. Any such sales of excess RINs are recorded in cost of materials and other on the consolidated statements of income. The assets and liabilities associated with our RINs Obligation are considered recurring fair value measurements. See Note 13 for further information.

From time to time, Delek enters into future commitments to purchase or sell RINs at fixed prices and quantities, which are used to manage the costs associated with our RINs Obligation. These future RIN commitment contracts meet the definition of derivative instruments under ASC 815, Derivatives and Hedging ("ASC 815"), and are measured at fair value based on quoted prices from an independent pricing service. Changes in the fair value of these future RIN commitment contracts are recorded in cost of materials and other on the consolidated statements of income. See Note 12 for further information.

Delek records all derivative financial instruments, including any interest rate swap and cap agreements, fuel-related derivatives, over the counter ("OTC") future swaps, forward contracts and future RIN purchase and sales commitments that qualify as derivative instruments, at estimated fair value in accordance with the provisions of ASC 815. Changes in the fair value of the derivative instruments are recognized in operations, unless we elect to apply and qualify for the hedging treatment permitted under the provisions of ASC 815 allowing such changes to be classified as other comprehensive income for cash flow hedges. We validate the fair value of all derivative financial instruments on a periodic basis, utilizing exchange pricing and/or price index developers such as Platts, Argus or OPIS. On a regular basis, Delek enters into commodity contracts with counterparties for the purchase or sale of crude oil, blendstocks, and various finished products. These contracts usually qualify for the normal purchase / normal sale exemption under ASC 815 and, as such, are not measured at fair value.

Delek applies the provisions of ASC 820, Fair Value Measurements and Disclosure ("ASC 820"), which defines fair value, establishes a framework for its measurement and expands disclosures about fair value measurements. ASC 820 applies to our commodity and interest rate derivatives that are measured at fair value on a recurring basis. ASC 820 also applies to the measurement of our equity method investment, goodwill and long-lived tangible and intangible assets when determining whether or not an impairment exists, when circumstances require evaluation. See Note 7 for further information. This standard also requires that we assess the impact of nonperformance risk on our derivatives. Nonperformance risk is not considered material to our financial statements as of December 31, 2018 and 2017.

Delek also applies the provisions of ASC 825 as it pertains to the fair value option. This standard permits the election to carry financial instruments and certain other items similar to financial instruments at fair value on the balance sheet, with all changes in fair value reported in earnings. By electing the fair value option, we can achieve an accounting result similar to a fair value hedge without having to follow the complex hedge accounting rules. As of both December 31, 2018 and 2017, we elected to account for the market-indexed step-out liabilities associated with our applicable Master Supply and Offtake Agreements (the "Supply and Offtake Agreements" or the "J. Aron Agreements") with J. Aron & Company ("J. Aron") at fair value and recognize all changes in the fair value of the step-out liabilities in cost of materials and other in the accompanying statements of income. Additionally, at December 31, 2018 we continue to apply our fair value election to our amended fixed-price step-out liabilities where changes in fair value relate to interest rate risk and therefore are recognized in interest expense in the accompanying statements of income. See Notes 10 and 13 for further discussion.

Delek has varying deductibles or self-insured retentions on our workers’ compensation, general liability, automobile liability insurance and medical claims for certain employees with coverage above the deductibles or self-insured retentions in amounts management considers adequate. We maintain an accrual for these costs based on claims filed and an estimate of claims incurred but not reported. Differences between actual settlements and recorded accruals are recorded in the period identified.

It is Delek's policy to accrue environmental and clean-up related costs of a non-capital nature when it is both probable that a liability has been incurred and the amount can be reasonably estimated. Environmental liabilities represent the current estimated costs to investigate and remediate contamination at our properties. This estimate is based on internal and third-party assessments of the extent of the contamination, the selected remediation technology and review of applicable environmental regulations, typically considering estimated activities and costs for 15 years, and up to 30 years if a longer period is believed reasonably necessary. Accruals for estimated costs from environmental remediation obligations generally are recognized no later than completion of the remedial feasibility study and include, but are not limited to, costs to perform remedial actions and costs of machinery and equipment that are dedicated to the remedial actions and that do not have an alternative use. Such accruals are adjusted as further information develops or circumstances change. We discount environmental liabilities to their present value if payments are fixed and determinable. Expenditures for equipment necessary for environmental issues relating to ongoing operations are capitalized.

In the refining segment, we have asset retirement obligations with respect to our refineries due to various legal obligations to clean and/or dispose of these assets at the time they are retired. However, the majority of these assets can be used for extended and indeterminate periods of time provided that they are properly maintained and/or upgraded. It is our practice and intent to continue to maintain these assets and make improvements based on technological advances. In the logistics segment, these obligations relate to the required cleanout of the pipeline and terminal tanks and removal of certain above-grade portions of the pipeline situated on right-of-way property. In the retail segment, we have asset retirement obligations related to the removal of underground storage tanks and the removal of brand signage at owned and leased retail sites which are legally required under the applicable leases. The asset retirement obligation for storage tank removal on leased retail sites is accreted over the expected life of the owned retail site or the average retail site lease term.

In order to determine fair value, management must make certain estimates and assumptions including, among other things, projected cash flows, a credit-adjusted risk-free rate and an assessment of market conditions that could significantly impact the estimated fair value of the asset retirement obligations. We believe the estimates selected, in each instance, represent our best estimate of future outcomes, but the actual outcomes could differ from the estimates selected.

The Company recognizes revenue when it satisfies a performance obligation by transferring control over a product or by providing services to a customer. The adoption of ASC 606, Revenue from Contracts with Customers ("ASC 606"), did not materially change our revenue recognition patterns, which are described below by reportable segment. The principles for recognizing revenue as codified in ASC 605, Revenue Recognition ("ASC 605"), were applied during the years ended December 31, 2017 and 2016. No restatements to revenues or expenses were required to be made to our consolidated statements of income, as we applied the modified retrospective transition method in adopting ASC 606, as described below under "—New Accounting Pronouncements Adopted During 2018—ASU 2014-09, Revenue - Revenue from Contracts with Customers."

Revenues for products sold are recorded at the point of sale upon delivery of product, which is the point at which title to the product is transferred, the customer has accepted the product and the customer has significant risks and rewards of owning the product. We typically have a right to payment once control of the product is transferred to the customer. Transaction prices for these products are typically at market rates for the product at the time of delivery. Payment terms require customers to pay shortly after delivery and do not contain significant financing components.

Revenues for products sold are generally recognized upon delivery of the product, which is when title and control of the product is transferred. Transaction prices for these products are typically at market rates for the product at the time of delivery. Service revenues are recognized as crude oil, intermediate and refined product are shipped through, delivered by or stored in our pipelines, trucks, terminals and storage facility assets, as

Fuel and merchandise revenue is recognized at the point of sale, which is when control of the product is transferred to the customer. Payments from customers are received at the time sales occur in cash or by credit or debit card. We derive service revenues from the sale of lottery tickets, money orders, car washes and other ancillary product and service offerings. Service revenue and related costs are recorded at gross amounts or net amounts, as appropriate, in accordance with the principal versus agent provisions in ASC 606.

For the refining segment, cost of materials and other includes (i) the direct cost of materials (such as crude oil and other refinery feedstocks, refined petroleum products and blendstocks, and ethanol feedstocks and products) that are a component of our products sold; (ii) costs related to the delivery (such as shipping and handling costs) or products sold; (iii) costs related to our environmental credit obligations to comply with various governmental and regulatory programs (such as the cost of renewable identification numbers as required by the EPA's Renewable Fuel Standard and emission credits under various cap-and-trade systems); and (iv) gains and losses on our commodity derivative instruments.

For the logistics segment, cost of materials and other includes (i) all costs of purchased refined products, additives and related transportation of such products, (ii) it also includes costs associated with the operation of our trucking assets, which primarily include allocated employee costs and other costs related to fuel, truck leases and repairs and maintenance, (iii) the cost of pipeline capacity leased from a third-party, and (iv) gains and losses related to our commodity hedging activities.

Operating expenses for the logistics segment include the costs associated with the operation of owned terminals and pipelines and terminalling expenses at third-party locations, excluding depreciation and amortization. These costs primarily include outside services, allocated employee costs, repairs and maintenance costs and energy and utility costs. Operating expenses related to the wholesale business are excluded from cost of sales because they primarily relate to costs associated with selling the products through our wholesale business.

For the retail segment, cost of materials and other comprises the costs related to specific products sold at retail sites, primarily consisting of motor fuels and merchandise. Retail fuel cost of sales represents the cost of purchased fuel, including transportation costs. Merchandise cost of sales includes the delivered cost of merchandise purchases, net of merchandise rebates and commissions. Operating expenses related to the retail business include costs such as wages of employees, lease expense, utility expense and other costs of operating the stores, excluding depreciation and amortization, and are excluded from cost of sales because they primarily relate to costs associated with selling the products through our retail sites.

Interest expense includes interest expense on debt, letters of credit, financing fees (including certain J. Aron fees associated with our Supply and Offtake Agreements), the amortization, net of accretion, of debt discounts or premium and amortization of deferred debt issuance costs, and interest rate swap settlements, but excludes capitalized interest. Original issuance discount and debt issuance costs are amortized ratably over the term of the related debt when it is not materially different from the effective interest method.

Prior to the adoption of ASC 606, Delek's policy was to exclude sales, use and excise taxes from revenue when we are an agent of the taxing authority, in accordance with the applicable guidance in ASC 605, Revenue Recognition. Upon the adoption of ASC 606, we made the accounting policy election to exclude from revenue all taxes assessed by a governmental authority, including sales, use and excise taxes, that are both imposed on and concurrent with a specific revenue-producing transaction and collected from a customer.

Deferred financing costs associated with our revolving credit facilities are included in other non-current assets in the accompanying consolidated balance sheets. Deferred financing costs associated with our term loan facilities are included as a reduction to the associated debt balance in the accompanying consolidated balance sheets. These costs represent expenses related to issuing our long-term debt and obtaining our lines of credit and are amortized ratably over the remaining term of the respective financing when it is not materially different from the effective interest method and included in interest expense in the accompanying consolidated statements of income. See Note 11 for further information.

In accordance with ASC 840-20, Leases - Operating Leases ("ASC 840-20"), for all leases that include fixed rental rate increases, Delek calculates the total rent expense for the entire lease period, considering renewals for all periods for which failure to renew the lease imposes economic penalty, and records rental expense on a straight-line basis in the accompanying consolidated statements of income. See Note 14 for further information.

Income taxes are accounted for under the provisions of ASC 740, Income Taxes ("ASC 740"). This statement generally requires Delek to record deferred income taxes for the differences between the book and tax bases of its assets and liabilities, which are measured using enacted tax rates and laws that will be in effect when the differences are expected to reverse. Deferred income tax expense or benefit represents the net change during the year in our deferred income tax assets and liabilities, exclusive of the amounts held in other comprehensive income.

ASC 740 also prescribes a comprehensive model for how companies should recognize, measure, present and disclose in their financial statements uncertain tax positions taken or expected to be taken on a tax return and prescribes the minimum recognition threshold a tax position is required to meet before being recognized in the financial statements. Finally, ASC 740 requires an annual tabular roll-forward of unrecognized tax benefits.

The Tax Cuts and Jobs Act (the "Tax Reform Act") was enacted on December 22, 2017. The Tax Reform Act reduces the US federal corporate tax rate from 35% to 21%, provides for immediate deduction of qualified capital assets placed in service, requires companies to pay a one-time transition tax on earnings of certain foreign subsidiaries that were previously tax deferred and creates new taxes on certain foreign sourced earnings. At December 31, 2018, we have finalized our accounting analysis based on the guidance, interpretations, and data available. Adjustments made in the fourth quarter of fiscal 2018 upon finalization of our accounting analysis were not material to our Consolidated Financial Statements. See Note 15 for further discussion.

ASC 718, Compensation - Stock Compensation ("ASC 718"), requires the cost of all share-based payments to employees, including grants of employee stock options, to be recognized in the income statement and establishes fair value as the measurement objective in accounting for share-based payment arrangements. ASC 718 requires the use of a valuation model to calculate the fair value of stock-based awards on the date of grant. Delek uses the Black-Scholes-Merton option-pricing model to determine the fair value of stock option and stock appreciation right (SAR) awards.

Restricted stock units ("RSUs") are valued based on the fair market value of the underlying stock on the date of grant. Performance-based RSUs ("PRSUs") include a market condition based on the Company's total shareholder return over the performance period and are valued using a Monte-Carlo simulation model. We record compensation expense for these awards based on the grant date fair value of the award, recognized ratably over the measurement period. Vested RSUs and PRSUs are not issued until the minimum statutory withholding requirements have been remitted to us for payment to the taxing authority. As a result, the actual number of shares accounted for as issued may be less than the number of RSUs vested, due to any withholding amounts which have not been remitted.

We generally recognize compensation expense related to stock-based awards with graded or cliff vesting on a straight-line basis over the vesting period. It is our practice to issue new shares when share-based awards are exercised. Our equity-based compensation expense includes estimates for forfeitures and volatility based on our historical experience. If actual forfeitures differ from our estimates, we adjust equity-based compensation expense accordingly.

In connection with the Delek/Alon Merger, we assumed defined benefit pension and postretirement medical plans for certain former Alon employees. We recognize the underfunded status of our defined benefit pension and postretirement medical plans as a liability. Changes in the funded status of our defined benefit pension and postretirement medical plans are recognized in other comprehensive income in the period when the changes occur. The funded status represents the difference between the projected benefit obligation and the fair value of the plan assets. The projected benefit obligation is the present value of benefits earned to date by plan participants, including the effect of assumed future salary increases. Plan assets are measured at fair value. We use December 31 of each year, or more frequently as necessary, as the measurement date for plan assets and obligations for all of our defined benefit pension and postretirement medical plans. We straight-line amortize prior service costs and actuarial gains and losses over the average future service of members expected to receive benefits and use a 10% corridor in regards to the actuarial gains and losses. See Note 22 for more information regarding our postretirement benefits.

In February 2018, the FASB issued guidance that allows a reclassification from accumulated other comprehensive income ("AOCI") to retained earnings for stranded tax effects resulting from the Tax Reform Act, which was signed into law on December 22, 2017. Consequently, the amendments eliminate the stranded tax effects related to items in accumulated other comprehensive income resulting from the Tax Reform Act. The new guidance may be applied retrospectively to each period in which the effect of the Tax Reform Act is recognized, or in the period of adoption. This guidance is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted. We elected to early adopt this guidance effective January 1, 2018. As a result of adopting this guidance, we reclassified $1.6 million from AOCI to retained earnings. See Note 15 for further discussion.

In May 2017, the FASB issued guidance that clarifies when changes to the terms or conditions of a share-based payment award must be accounted for as modifications. The modification accounting guidance applies if the value, vesting conditions or classification of the award changes. This guidance is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. This guidance should be applied prospectively to an award modified on or after the adoption date. We adopted this guidance on January 1, 2018 and the adoption did not have a material impact on our business, financial condition or results of operations.

In March 2017, the FASB issued guidance that will require that an employer disaggregate the service cost component from the other components of net benefit cost with respect to defined benefit postretirement employee benefit plans. Service cost is required to be reported in the same line item or items as other compensation costs arising from services rendered by the pertinent employees during the period. The other components of net periodic benefit cost are required to be reported outside the subtotal for operating income. Additionally, only the service cost component of net benefit costs are eligible for capitalization. The guidance became effective January 1, 2018. We adopted this guidance on January 1, 2018, which retrospectively impacted the presentation of our third and fourth quarter 2017 statements of income as a result of the pension and postretirement obligations assumed in the Delek/Alon Merger. As further discussed in Note 22, only the service cost component of net periodic benefit costs are included as part of general and administrative expenses in the accompanying consolidated statements of income. The other components of net periodic benefit costs are included as part of other non-operating expenses (income), net. As a practical expedient, we used the amounts disclosed regarding our pension and other postretirement benefit plans for the prior comparative periods as the estimation basis for applying the retrospective presentation requirements. The following table details the impact of the retrospective adoption of this standard for the year ended December 31, 2017:

In February 2017, the FASB issued guidance clarifying the scope of asset derecognition guidance and accounting for partial sales of nonfinancial assets. The amendments in this guidance should be applied using either i) a modified retrospective basis through a cumulative-effect adjustment directly to retained earnings as of the beginning of the period of adoption or ii) a retrospective basis to each period presented in the financial statements. This guidance is effective for annual reporting periods beginning after December 15, 2017, including interim reporting periods within

In January 2017, the FASB issued guidance concerning the goodwill impairment test that eliminates Step 2, which required a comparison of the implied fair value of goodwill of the reporting unit with the carrying amount of that goodwill for that reporting unit. It also 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 assessment, to perform Step 2 of the goodwill impairment test. An entity still has the option to perform the qualitative assessment for a reporting unit to determine if the quantitative impairment test is necessary. This guidance is effective for annual or any interim goodwill impairment tests in fiscal years beginning after December 15, 2019. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. As permitted under ASU 2017-04, we adopted this guidance in the fourth quarter of 2018 in connection with our 2018 goodwill impairment tests. The adoption did not have a material impact on our business, financial condition or results of operations.

In October 2016, the FASB issued guidance that requires an entity to recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. This guidance is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. We adopted this guidance on January 1, 2018. As a result of adopting this guidance, we decreased retained earnings by $44.4 million for the cumulative effect as of January 1, 2018.

In August 2016, the FASB issued guidance that clarifies eight cash flow classification issues pertaining to cash receipts and cash payments. This guidance is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. We adopted this guidance on January 1, 2018 and the adoption did not have a material impact on our business, financial condition or results of operations, except for reclassifications of certain distributions received from equity method investees, due to Delek making an accounting policy election to classify distributions received from equity method investees using the cumulative earnings approach. Under this approach, distributions received are considered returns on investment and classified as cash inflows from operating activities, unless the investor’s cumulative distributions received less distributions received in prior periods that were determined to be returns of investment exceed cumulative equity in earnings (as adjusted for amortization of basis differences) recognized by the investor. When such an excess occurs, the current-period distribution up to this excess should be considered a return of investment and classified as cash inflows from investing activities. This resulted in a reclassification of $12.4 million and $20.2 million of distributions received for the years ended December 31, 2017 and 2016, respectively, from the line item entitled dividends from equity method investments in net cash provided by (used in) operating activities to the line item entitled distributions from equity method investments in net cash provided by (used in) investing activities in the consolidated statements of cash flows.

In January 2016, the FASB issued guidance that affects the accounting for equity investments, financial liabilities accounted for under the fair value option and the presentation and disclosure requirements for financial instruments. Under the new guidance, all equity investments in unconsolidated entities (other than those accounted for using the equity method of accounting) will generally be measured at fair value through earnings. There will no longer be an available-for-sale classification for equity securities with readily determinable fair values. For financial liabilities when the fair value option has been elected, changes in fair value due to instrument-specific credit risk will be recognized separately in other comprehensive income. It will require public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes and separate presentation of financial assets and financial liabilities by measurement category and form of financial asset, and will eliminate the requirement for public business entities to disclose the method and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost. The new guidance is effective for annual reporting periods beginning after December 15, 2017, including interim reporting periods within that reporting period. We adopted this guidance on January 1, 2018 and the adoption did not have a material impact on our business, financial condition or results of operations.

In May 2014, the FASB issued guidance as codified in ASC 606 to clarify the principles for recognizing revenue. The core principle of the new guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The guidance also requires improved interim and annual disclosures that enable the users of financial statements to better understand the nature, amount, timing, and uncertainty of revenues and cash flows arising from contracts with customers. The new guidance is effective for annual reporting periods beginning after December 15, 2017, including interim reporting periods within that reporting period, and can be adopted retrospectively. We adopted this guidance on January 1, 2018, using the modified retrospective transition method applied to contracts which were not completed as of January 1, 2018, and the adoption did not have a material impact on our business, financial condition or results of operations.

In August 2018, the Financial Accounting Standards Board (the "FASB") issued guidance related to customers’ accounting for implementation costs incurred in a cloud computing arrangement that is considered a service contract. This pronouncement aligns the requirements for capitalizing implementation costs in such arrangements with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. This pronouncement is effective for fiscal years, and for interim periods within those fiscal years, beginning after December 15, 2019. Early adoption is permitted, including adoption in any interim period for which financial statements have not been issued. Entities can choose to adopt the new guidance prospectively or retrospectively. We expect to adopt this guidance on or before the effective date and are currently evaluating the impact that adopting this new guidance will have on our business, financial condition and results of operations.

In August 2018, the FASB issued guidance related to disclosure requirements for defined benefit plans. The pronouncement eliminates, modifies and adds disclosure requirements for defined benefit plans. The pronouncement is effective for fiscal years ending after December 15, 2020, and early adoption is permitted. We expect to adopt this guidance on or before the effective date and do not expect adopting this new guidance will have a material impact on our business, financial condition or results of operations.

In August 2018, the FASB issued guidance related to disclosure requirements for fair value measurements. The pronouncement eliminates, modifies and adds disclosure requirements for fair value measurements. The pronouncement is effective for fiscal years, and for interim periods within those fiscal years, beginning after December 15, 2019, with early adoption permitted. We expect to adopt this guidance on or before the effective date and do not expect adopting this new guidance will have a material impact on our business, financial condition or results of operations.

In August 2017, the FASB issued guidance to better align financial reporting for hedging activities with the economic objectives of those activities for both financial (e.g., interest rate) and commodity risks. The guidance was intended to create more transparency in the presentation of financial results, both on the face of the financial statements and in the footnotes, and simplify the application of hedge accounting guidance. This guidance is effective for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Companies are required to apply the guidance on a modified retrospective transition method in which the cumulative effect of the change will be recognized within equity in the consolidated balance sheet as of the date of adoption. Early adoption is permitted, including in an interim period. If a company early adopts in an interim period, any adjustments should be reflected as of the beginning of the fiscal year that includes the interim period. We expect to adopt this guidance on or before the effective date and are currently evaluating the impact that adopting this new guidance will have on our business, financial condition and results of operations.

In June 2016, the FASB issued guidance requiring the measurement of all expected credit losses for financial assets held at the reporting date based on historical experience, current conditions, and reasonable and supportable forecasts. Financial institutions and other organizations will now use forward-looking information to better inform their credit loss estimates. This guidance is effective for interim and annual periods beginning after December 15, 2019. We expect to adopt this guidance on or before the effective date and are currently evaluating the impact that adopting this new guidance will have on our business, financial condition and results of operations.