Accounting Policies (Policies)	9 Months Ended
Accounting Policies (Policies)	Sep. 30, 2018
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The consolidated financial statements include the accounts of Getty Realty Corp. and its wholly-owned subsidiaries. The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). We do not distinguish our principal business or our operations on a geographical basis for purposes of measuring performance. We manage and evaluate our operations as a single segment. All significant intercompany accounts and transactions have been eliminated. Certain reclassifications have been made to prior period amounts in order to conform to current period presentation.
Unaudited, Interim Consolidated Financial Statements	Unaudited, Interim Consolidated Financial Statements The consolidated financial statements are unaudited but, in our opinion, reflect all adjustments (consisting of normal recurring accruals) necessary for a fair statement of the results for the periods presented. These statements should be read in conjunction with the consolidated financial statements and related notes in our Annual Report on Form 10-K for the year ended December 31, 2017.
Use of Estimates, Judgments and Assumptions	Use of Estimates, Judgments and Assumptions The consolidated financial statements have been prepared in conformity with GAAP, which requires management to make estimates, judgments and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and revenues and expenses during the period reported. Estimates, judgments and assumptions underlying the accompanying consolidated financial statements include, but are not limited to, real estate, receivables, deferred rent receivable, direct financing leases, depreciation and amortization, impairment of long-lived assets, environmental remediation costs, environmental remediation obligations, litigation, accrued liabilities, income taxes and the allocation of the purchase price of properties acquired to the assets acquired and liabilities assumed. Application of these estimates and assumptions requires exercise of judgment as to future uncertainties and, as a result, actual results could differ materially from these estimates.
Real Estate	Real Estate Real estate assets are stated at cost less accumulated depreciation and amortization. For acquisitions of real estate which are accounted for as business combinations, we estimate the fair value of acquired tangible assets (consisting of land, buildings and improvements) “as if vacant” and identified intangible assets and liabilities (consisting of leasehold interests, above-market and below-market leases, in-place leases and tenant relationships) and assumed debt. Based on these estimates, we allocate the estimated fair value to the applicable assets and liabilities. Fair value is determined based on an exit price approach, which contemplates the price that would be received from the sale of an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. We expense transaction costs associated with business combinations in the period incurred. Acquisitions of real estate which do not meet the definition of a business are accounted for as asset acquisitions. The accounting model for asset acquisitions is similar to the accounting model for business combinations except that the acquisition costs are capitalized and allocated to the individual assets acquired and liabilities assumed on a relative fair value basis. See Note 11 for additional information regarding property acquisitions. We capitalize direct costs, including costs such as construction costs and professional services, and indirect costs associated with the development and construction of real estate assets while substantive activities are ongoing to prepare the assets for their intended use. The capitalization period begins when development activities are underway and ends when it is determined that the asset is substantially complete and ready for its intended use. We evaluate the held for sale classification of our real estate as of the end of each quarter. Assets that are classified as held for sale are recorded at the lower of their carrying amount or fair value less costs to sell. When real estate assets are sold or retired, the cost and related accumulated depreciation and amortization is eliminated from the respective accounts and any gain or loss is credited or charged to income. We evaluate real estate sale transactions where we provide seller financing to determine sale and gain recognition in accordance with GAAP. Expenditures for maintenance and repairs are charged to income when incurred.
Direct Financing Leases	Direct Financing Leases Income under direct financing leases is included in revenues from rental properties and is recognized over the lease terms using the effective interest rate method which produces a constant periodic rate of return on the net investments in the leased properties. The investments in direct financing leases are increased for interest income earned and amortized over the life of the leases and reduced by the receipt of lease payments. We consider direct financing leases to be past-due or delinquent when a contractually required payment is not remitted in accordance with the provisions of the underlying agreement. We evaluate each account individually and set up an allowance when, based upon current information and events, it is probable that we will be unable to collect all amounts due according to the existing contractual terms and the amount can be reasonably estimated. We review our direct financing leases at least annually to determine whether there has been an other-than-temporary decline in the current estimate of residual value of the property. The residual value is our estimate of what we could realize upon the sale of the property at the end of the lease term, based on market information and third-party estimates where available. If this review indicates that a decline in residual value has occurred that is other-than-temporary, we recognize an impairment charge. There were no impairments of any of our direct financing leases during the three and nine months ended September 30, 2018 and 2017. When we enter into a contract to sell properties that are recorded as direct financing leases, we evaluate whether we believe that it is probable that the disposition will occur. If we determine that the disposition is probable and therefore the property’s holding period is reduced, we record an allowance for credit losses to reflect the change in the estimate of the undiscounted future rents. Accordingly, the net investment balance is written down to fair value.
Notes and Mortgages Receivable	Notes and Mortgages Receivable Notes and mortgages receivable consists of loans originated by us in conjunction with property dispositions and funding provided to tenants in conjunction with property acquisitions and capital improvements. Notes and mortgages receivable are recorded at stated principal amounts. We evaluate the collectability of both interest and principal on each loan to determine whether it is impaired. A loan is considered to be impaired when, based upon current information and events, it is probable that we will be unable to collect all amounts due under the existing contractual terms. When a loan is considered to be impaired, the amount of the loss is calculated by comparing the recorded investment to the fair value determined by discounting the expected future cash flows at the loan’s effective interest rate or to the fair value of the underlying collateral, if the loan is collateralized. Interest income on performing loans is accrued as earned. Interest income on impaired loans is recognized on a cash basis. We do not provide for an additional allowance for loan losses based on the grouping of loans, as we believe that the characteristics of the loans are not sufficiently similar to allow an evaluation of these loans as a group for a possible loan loss allowance. As such, all of our loans are evaluated individually for impairment purposes. There were no impairments related to our notes and mortgages receivable during the three and nine months ended September 30, 2018 and 2017.
Revenue Recognition and Deferred Rent Receivable	Revenue Recognition and Deferred Rent Receivable On January 1, 2018, we adopted ASU 2014-09, Revenue from Contracts with Customers (Topic 606), (“Topic 606”) using the modified retrospective method applying it to any open contracts as of January 1, 2018. The new guidance provides a unified model to determine how revenue is recognized. To determine the proper amount of revenue to be recognized, we perform the following steps: (i) identify the contract with the customer, (ii) identify the performance obligations within the contract, (iii) determine the transaction price, (iv) allocate the transaction price to the performance obligations and (v) recognize revenue when (or as) a performance obligation is satisfied. We concluded that our revenue consists of rental income from leasing arrangements, which is specifically excluded from the standard, and thus had no material impact on our consolidated financial statements or notes to our consolidated financial statements as of September 30, 2018. Minimum lease payments from operating leases are recognized on a straight-line basis over the term of the leases. The cumulative difference between lease revenue recognized under this method and the contractual lease payment terms is recorded as deferred rent receivable on our consolidated balance sheets. We reserve for a portion of the recorded deferred rent receivable if circumstances indicate that a tenant will not make all of its contractual lease payments during the current lease term. We make estimates of the collectability of our accounts receivable related to revenue from rental properties. We analyze accounts receivable and historical bad debt levels, customer creditworthiness and current economic trends when evaluating the adequacy of the allowance for doubtful accounts. Additionally, with respect to tenants in bankruptcy, we estimate the expected recovery through bankruptcy claims and increase the allowance for amounts deemed uncollectible. If our assumptions regarding the collectability of accounts receivable prove incorrect, we could experience write-offs of the accounts receivable or deferred rent receivable in excess of our allowance for doubtful accounts. The present value of the difference between the fair market rent and the contractual rent for above-market and below-market leases at the time properties are acquired is amortized into revenues from rental properties over the remaining terms of the in-place leases. Lease termination fees are recognized as other income when earned upon the termination of a tenant’s lease and relinquishment of space in which we have no further obligation to the tenant. The sales of nonfinancial assets, such as real estate, are to be recognized when control of the asset transfers to the buyer, which will occur when the buyer has the ability to direct the use of or obtain substantially all of the remaining benefits from the asset. This generally occurs when the transaction closes and consideration is exchanged for control of the property. During the nine months ended September 30, 2018, we disposed of six properties, in separate transactions, which resulted in an aggregate gain of $3,665,000, included in gain on dispositions of real estate, on our consolidated statements of operations. We also received funds from a property condemnation resulting in a loss of $29,000, included in gain on dispositions of real estate on our consolidated statements of operations.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets Assets are written down to fair value when events and circumstances indicate that the assets might be impaired and the projected undiscounted cash flows estimated to be generated by those assets are less than the carrying amount of those assets. Assets held for disposal are written down to fair value less estimated disposition costs. We recorded impairment charges aggregating $832,000 and $4,808,000 for the three and nine months ended September 30, 2018, respectively, and $2,393,000 and $7,044,000 for the three and nine months ended September 30, 2017, respectively, in continuing and discontinued operations. Our estimated fair values, as they relate to property carrying values, were primarily based upon (i) estimated sales prices from third-party offers based on signed contracts, letters of intent or indicative bids, for which we do not have access to the unobservable inputs used to determine these estimated fair values, and/or consideration of the amount that currently would be required to replace the asset, as adjusted for obsolescence (this method was used to determine $2,531,000 of the $4,808,000 in impairments recognized during the nine months ended September 30, 2018) and (ii) discounted cash flow models (this method was used to determine $104,000 of the $4,808,000 in impairments recognized during the nine months ended September 30, 2018). During the nine months ended September 30, 2018, we recorded $2,173,000 of the $4,808,000 in impairments recognized due to the accumulation of asset retirement costs as a result of changes in estimates associated with our estimated environmental liabilities which increased the carrying values of certain properties in excess of their fair values. The estimated fair value of real estate is based on the price that would be received from the sale of the property in an orderly transaction between market participants at the measurement date. In general, we consider multiple internal valuation techniques when measuring the fair value of a property, all of which are based on unobservable inputs and assumptions that are classified within Level 3 of the Fair Value Hierarchy. These unobservable inputs include assumed holding periods ranging up to 15 years, assumed average rent increases of 2.0% annually, income capitalized at a rate of 8.0% and cash flows discounted at a rate of 7.0%. These assessments have a direct impact on our net income because recording an impairment loss results in an immediate negative adjustment to net income. The evaluation of anticipated cash flows is highly subjective and is based in part on assumptions regarding future rental rates and operating expenses that could differ materially from actual results in future periods. Where properties held for use have been identified as having a potential for sale, additional judgments are required related to the determination as to the appropriate period over which the projected undiscounted cash flows should include the operating cash flows and the amount included as the estimated residual value. This requires significant judgment. In some cases, the results of whether impairment is indicated are sensitive to changes in assumptions input into the estimates, including the holding period until expected sale.
Fair Value of Financial Instruments	Fair Value of Financial Instruments All of our financial instruments are reflected in the accompanying consolidated balance sheets at amounts which, in our estimation based upon an interpretation of available market information and valuation methodologies, reasonably approximate their fair values, except those separately disclosed in the notes below. The preparation of consolidated financial statements in accordance with GAAP requires management to make estimates of fair value that affect the reported amounts of assets and liabilities and disclosure of assets and liabilities at the date of the consolidated financial statements and revenues and expenses during the period reported using a hierarchy (the “Fair Value Hierarchy”) that prioritizes the inputs to valuation techniques used to measure the fair value. The Fair Value Hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). The levels of the Fair Value Hierarchy are as follows: “Level 1” – inputs that reflect unadjusted quoted prices in active markets for identical assets or liabilities that we have the ability to access at the measurement date; “Level 2” – inputs other than quoted prices that are observable for the asset or liability either directly or indirectly, including inputs in markets that are not considered to be active; and “Level 3” – inputs that are unobservable. Certain types of assets and liabilities are recorded at fair value either on a recurring or non-recurring basis. Assets required or elected to be marked-to-market and reported at fair value every reporting period are valued on a recurring basis. Other assets not required to be recorded at fair value every period may be recorded at fair value if a specific provision or other impairment is recorded within the period to mark the carrying value of the asset to market as of the reporting date. Such assets are valued on a non-recurring basis.
Environmental Remediation Obligations	Environmental Remediation Obligations We record the fair value of a liability for an environmental remediation obligation as an asset and liability when there is a legal obligation associated with the retirement of a tangible long-lived asset and the liability can be reasonably estimated. Environmental remediation obligations are estimated based on the level and impact of contamination at each property. The accrued liability is the aggregate of our estimate of the fair value of cost for each component of the liability. The accrued liability is net of estimated recoveries from state underground storage tank (“UST”) remediation funds considering estimated recovery rates developed from prior experience with the funds. Net environmental liabilities are currently measured based on their expected future cash flows which have been adjusted for inflation and discounted to present value. We accrue for environmental liabilities that we believe are allocable to other potentially responsible parties if it becomes probable that the other parties will not pay their environmental remediation obligations.
Income Taxes	Income Taxes We and our subsidiaries file a consolidated federal income tax return. Effective January 1, 2001, we elected to qualify, and believe that we are operating so as to qualify, as a REIT for federal income tax purposes. Accordingly, we generally will not be subject to federal income tax on qualifying REIT income, provided that distributions to our stockholders equal at least the amount of our taxable income as defined under the Internal Revenue Code. We accrue for uncertain tax matters when appropriate. The accrual for uncertain tax positions is adjusted as circumstances change and as the uncertainties become more clearly defined, such as when audits are settled or exposures expire. Tax returns for the years 2015, 2016 and 2017, and tax returns which will be filed for the year ended 2018, remain open to examination by federal and state tax jurisdictions under the respective statutes of limitations.
New Accounting Pronouncements	New Accounting Pronouncements In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) (“ASU 2016-02”). ASU 2016-02 amends the existing accounting standards for lease accounting, including requiring lessees to recognize most leases on their balance sheets. Under ASU 2016-02 lessor accounting will remain similar to lessor accounting under previous GAAP, while aligning with the FASB’s new revenue recognition guidance. ASU 2016-02 is effective for fiscal years, and for interim periods within those years, beginning January 1, 2019. Early adoption of ASU 2016-02 is permitted. The standard requires a modified retrospective transition approach for all leases existing at, or entered into after, the date of initial application, with an option to use certain transition relief. In July 2018, the FASB issued ASU 2018-10, Codification Improvements to Topic 842, Leases, to clarify how to apply certain aspects of the new leases standard. In July 2018, the FASB also issued ASU 2018-11, Leases (Topic 842): Targeted Improvements, to give entities another option for transition and to provide lessors with a practical expedient to reduce the cost and complexity of implementing the new standard. The transition option allows entities to not apply the new leases standard in the comparative periods they present in their financial statements in the year of adoption. The above ASUs are effective for fiscal years, and for interim periods within those years, beginning January 1, 2019. Early adoption is permitted. We plan to adopt these standards on January 1, 2019, and are continuing to evaluate the impact of their adoption on our consolidated financial statements. However, we currently believe that the adoption of the above ASUs will not have a material impact for operating leases where we are a lessor and we will continue to record revenues from rental properties for our operating leases on a straight-line basis. However, for leases where we are a lessee we expect to record a lease liability and a right of use asset on our consolidated financial statements at fair value upon adoption. The lease liability and right-of-use asset are to be carried at the present value of remaining expected future lease payments. On June 16, 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses (Topic 326): Measurements of Credit Losses on Financial Instruments (“ASU 2016-13”) to amend the accounting for credit losses for certain financial instruments. Under the new guidance, an entity recognizes its estimate of expected credit losses as an allowance, which the FASB believes will result in more timely recognition of such losses. ASU 2016-13 is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. We are currently evaluating the impact that the adoption of ASU 2016-13 will have on our consolidated financial statements. In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (“ASU 2016-15”). ASU 2016-15 is intended to clarify the presentation of cash receipts and payments in specific situations. The amendments in this update were effective for financial statements issued for annual periods beginning after December 15, 2017, including interim periods within those annual periods. Effective January 1, 2018, we adopted ASU 2016-15. The adoption of this guidance did not have an impact on our consolidated financial statements or notes to our consolidated financial statements. On February 22, 2017, the FASB issued ASU 2017-05, Other Income—Gains and Losses from the Derecognition of Nonfinancial Assets (Subtopic 610-20), Clarifying the Scope of Asset Derecognition Guidance and Accounting for Partial Sales of Nonfinancial Assets (“ASU 2017-05”) to provide guidance for recognizing gains and losses from the transfer of nonfinancial assets and in-substance non-financial assets in contracts with non-customers, unless other specific guidance applies. ASU 2017-05 requires a company to derecognize nonfinancial assets once it transfers control of a distinct nonfinancial asset or distinct in substance nonfinancial asset. As a result of the new guidance, the guidance specific to real estate sales in ASC 360-20 was eliminated. As such, sales and partial sales of real estate assets will now be subject to the same derecognition model as all other nonfinancial assets. ASU 2017-05 was effective for annual periods beginning after December 15, 2017, including interim periods within that reporting period. Effective January 1, 2018, we adopted ASU 2017-05 on a modified retrospective basis. Upon adoption, we apply the guidance to prospective disposals of nonfinancial assets within the scope of Subtopic 610-20. The adoption of this guidance did not have an impact on our consolidated financial statements or notes to our consolidated financial statements.