Summary of Significant Accounting Policies (Policies)	12 Months Ended
Summary of Significant Accounting Policies (Policies)	Dec. 31, 2018
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The consolidated financial statements are presented on the accrual basis of accounting in accordance with U.S. generally accepted accounting principles (“GAAP”) and include the accounts of the Company and its wholly- or majority-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.
Variable Interest Entities	Variable Interest Entities The Company accounts for arrangements that are not controlled through voting or similar rights as variable interest entities (“VIEs”). An enterprise is required to consolidate a VIE if it is the primary beneficiary of the VIE. A VIE is created when (i) the equity investment at risk is not sufficient to permit the entity to finance its activities without additional subordinated financial support from other parties, or (ii) the entity’s equity holders as a group either: (a) lack the power, through voting or similar rights, to direct the activities of the entity that most significantly impact the entity’s economic performance, (b) are not obligated to absorb expected losses of the entity if they occur, or (c) do not have the right to receive expected residual returns of the entity if they occur. If an entity is deemed to be a VIE, the enterprise that is deemed to have a variable interest, or combination of variable interests, that provides the enterprise with a controlling financial interest in the VIE, is considered the primary beneficiary and must consolidate the VIE. The Company has concluded that under certain circumstances when the Company enters into arrangements for the formation of joint ventures, a VIE may be created under condition (i), (ii) (b) or (c) of the previous paragraph. For each VIE created, the Company has performed a qualitative analysis, including considering which party, if any, has the power to direct the activities most significant to the economic performance of each VIE and whether that party has the obligation to absorb losses of the VIE or the right to receive benefits from the VIE that could be significant to the VIE. If the Company is determined to be the primary beneficiary of the VIE, the assets, liabilities and operations of the VIE are consolidated with the Company’s financial statements. Additionally, the Operating Partnership has notes payable to one trust that is a VIE under condition (ii)(a) above. Since the Operating Partnership is not the primary beneficiary of the trust, this VIE is not consolidated. The Company’s investments in real estate joint ventures, where the Company has significant influence, but not control, and joint ventures which are VIEs in which the Company is not the primary beneficiary, are recorded under the equity method of accounting on the accompanying consolidated financial statements.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP 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.
Fair Value Disclosures	Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis Long-lived assets held for use are evaluated for impairment when events or circumstances indicate there may be impairment. The Company reviews each store at least annually to determine if any such events or circumstances have occurred or exist. The Company focuses on stores where occupancy and/or rental income have decreased by a significant amount. For these stores, the Company determines whether the decrease is temporary or permanent, and whether the store will likely recover the lost occupancy and/or revenue in the short term. In addition, the Company reviews stores in the lease-up stage and compares actual operating results to original projections. When the Company determines that an event that may indicate impairment has occurred, the Company compares the carrying value of the related long-lived assets to the undiscounted future net operating cash flows attributable to the assets. An impairment loss is recorded if the net carrying value of the assets exceeds the undiscounted future net operating cash flows attributable to the assets. The impairment loss recognized equals the excess of net carrying value over the related fair value of the assets. When real estate assets are identified by management as held for sale, the Company discontinues depreciating the assets and estimates the fair value of the assets, net of selling costs. The Company compares the carrying value of the related long-lived assets to the undiscounted future net operating cash flows attributable to the assets (categorized within Level 3 of the fair value hierarchy). If the estimated fair value, net of selling costs, of the assets that have been identified as held for sale is less than the net carrying value of the assets, the Company would recognize a loss on the assets held for sale. The operations of assets held for sale or sold during the period are presented as part of normal operations for all periods presented. The Company assesses annually whether there are any indicators that the value of the Company’s investments in unconsolidated real estate ventures may be impaired and when events or circumstances indicate that there may be impairment. An investment is impaired if management’s estimate of the fair value of the investment is less than its carrying value. To the extent impairment has occurred, and is considered to be other than temporary, the loss is measured as the excess of the carrying amount of the investment over the fair value of the investment. As of December 31, 2018 and 2017, the Company did not have any assets or liabilities measured at fair value on a nonrecurring basis. Fair Value of Financial Instruments The carrying values of cash and cash equivalents, restricted cash, receivables, other financial instruments included in other assets, accounts payable and accrued expenses, variable-rate notes payable, revolving lines of credit and other liabilities reflected in the consolidated balance sheets at December 31, 2018 and 2017, approximate fair value. The fair values of the Company’s notes receivable from Preferred Operating Partnership unit holders and other fixed rate notes receivable were based on the discounted estimated future cash flow of the notes (categorized within Level 3 of the fair value hierarchy); the discount rate used approximated the current market rate for loans with similar maturities and credit quality. The fair values of the Company’s fixed rate notes payable and notes payable to trusts were estimated using the discounted estimated future cash payments to be made on such debt (categorized within Level 3 of the fair value hierarchy); the discount rates used approximated current market rates for loans, or groups of loans, with similar maturities and credit quality. The fair value of the Company’s exchangeable senior notes was estimated using an average market price for similar securities obtained from a third party. Fair Value Disclosures Derivative financial instruments Currently, the Company uses interest rate swaps to manage its interest rate risk. The valuation of these instruments is determined using widely accepted valuation techniques including discounted cash flow analysis on the expected cash flows of each derivative. This analysis reflects the contractual terms of the derivatives, including the period to maturity, and uses observable market-based inputs, including interest rate curves. The fair values of interest rate swaps are determined using the market standard methodology of netting the discounted future fixed cash payments and the discounted expected variable cash receipts. The variable cash receipts are based on an expectation of future interest rates (forward curves) derived from observable market interest rate forward curves. The Company incorporates credit valuation adjustments to appropriately reflect both its own nonperformance risk and the respective counterparty’s nonperformance risk in the fair value measurements. In adjusting the fair value of its derivative contracts for the effect of nonperformance risk, the Company has considered the impact of netting and any applicable credit enhancements, such as collateral postings, thresholds, mutual puts, and guarantees. In conjunction with the Financial Accounting Standard Board’s fair value measurement guidance, the Company made an accounting policy election to measure the credit risk of its derivative financial instruments that are subject to master netting agreements on a net basis by counterparty portfolio. Although the Company has determined that the majority of the inputs used to value its derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with its derivatives utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by itself and its counterparties. However, as of December 31, 2018, the Company has assessed the significance of the impact of the credit valuation adjustments on the overall valuation of its derivative positions and has determined that the credit valuation adjustments are not significant to the overall valuation of its derivatives. As a result, the Company has determined that its derivative valuations in their entirety are classified in Level 2 of the fair value hierarchy.
Real Estate Assets	Real Estate Assets Real estate assets are stated at cost, less accumulated depreciation. Direct and allowable internal costs associated with the development, construction, renovation, and improvement of real estate assets are capitalized. Interest, property taxes, and other costs associated with development incurred during the construction period are capitalized. The construction period begins when expenditures for the real estate assets have been made and activities that are necessary to prepare the asset for its intended use are in progress. The construction period ends when the asset is substantially complete and ready for its intended use. Expenditures for maintenance and repairs are charged to expense as incurred. Major replacements and betterments that improve or extend the life of the asset are capitalized and depreciated over their estimated useful lives. Depreciation is computed using the straight-line method over the estimated useful lives of the buildings and improvements, which are generally between five and 39 years. Stores purchased at the time of certificate of occupancy issuance and stores purchased subsequent to the Company's adoption of ASU 2017-01 on January 1, 2017 are considered asset acquisitions. As such, the purchase price is allocated to the real estate assets acquired based on their relative fair values, which are estimated using significant unobservable inputs. The value of the tangible assets, consisting of land and buildings, is determined as if vacant. Intangible assets, which represent the value of existing tenant relationships, are recorded at their relative fair values based on the avoided cost to replace the current leases. The Company measures the value of tenant relationships based on the rent lost due to the amount of time required to replace existing customers, which is based on the Company’s historical experience with turnover in its stores. Any debt assumed as part of the acquisition is recorded at fair value based on current interest rates compared to contractual rates. Acquisition-related transactions costs are capitalized as part of the purchase price. Intangible lease rights represent: (1) purchase price amounts allocated to leases on three stores that cannot be classified as ground or building leases; these rights are amortized to expense over the life of the leases and (2) intangibles related to ground leases on eight stores where the leases were assumed by the Company at rates that were lower than the current market rates for similar leases. The values associated with these assumed leases were recorded as intangibles, which will be amortized over the lease terms.
Investments in Unconsolidated Real Estate Ventures	Investments in Unconsolidated Real Estate Ventures The Company’s investments in real estate joint ventures, where the Company has significant influence, but not control and joint ventures which are VIEs in which the Company is not the primary beneficiary, are recorded under the equity method of accounting in the accompanying consolidated financial statements. Under the equity method, the Company’s investment in real estate ventures is stated at cost and adjusted for the Company’s share of net earnings or losses and reduced by distributions. Equity in earnings of real estate ventures is generally recognized based on the Company’s ownership interest in the earnings of each of the unconsolidated real estate ventures. For the purposes of presentation in the statement of cash flows, the Company follows the “look through” approach for classification of distributions from joint ventures. Under this approach, distributions are reported under operating cash flow unless the facts and circumstances of a specific distribution clearly indicate that it is a return of capital (e.g., a liquidating dividend or distribution of the proceeds from the joint venture’s sale of assets), in which case it is reported as an investing activity.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company’s cash is deposited with financial institutions located throughout the United States and at times may exceed federally insured limits. The Company considers all highly liquid debt instruments with a maturity date of three months or less to be cash equivalents.
Restricted Cash	Restricted Cash Restricted cash is comprised of letters of credit and escrowed funds deposited with financial institutions located throughout the United States relating to earnest money deposits on potential acquisitions, real estate taxes, insurance and capital expenditures.
Other Assets	Other Assets Other assets consist of equipment and fixtures, rents receivable from our tenants, investments in trusts, notes and other receivables, other intangible assets, deferred tax assets, prepaid expenses and the fair value of interest rate swaps. Depreciation of equipment and fixtures is computed on a straight-line basis over three to five years.
Derivative Instruments and Hedging Activities	Derivative Instruments and Hedging Activities The Company records all derivatives on the balance sheet at fair value. The accounting for changes in the fair value of derivatives depends on the intended use of the derivative, whether the Company has elected to designate a derivative in a hedging relationship and apply hedge accounting and whether the hedging relationship has satisfied the criteria necessary to apply hedge accounting. Derivatives designated and qualifying as a hedge of the exposure to changes in the fair value of an asset, liability or firm commitment attributable to a particular risk, such as interest rate risk, are considered fair value hedges. Derivatives designated and qualifying as a hedge of the exposure to variability in expected future cash flows, or other types of forecasted transactions, are considered cash flow hedges. Hedge accounting generally provides for the matching of the timing of gain or loss recognition on the hedging instrument with the recognition of the changes in the fair value of the hedged asset or liability that are attributable to the hedged risk in a fair value hedge or the earnings effect of the hedged forecasted transactions in a cash flow hedge. The Company may enter into derivative contracts that are intended to economically hedge certain of its risk, even though hedge accounting does not apply or the Company elects not to apply hedge accounting. The Company made an accounting policy election to measure the credit risk of its derivative financial instruments that are subject to master netting agreements on a net basis by counterparty portfolio.
Risk Management and Use of Financial Instruments	Risk Management and Use of Financial Instruments In the normal course of its ongoing business operations, the Company encounters economic risk. There are three main components of economic risk: interest rate risk, credit risk and market risk. The Company is subject to interest rate risk on its interest-bearing liabilities. Credit risk is the risk of inability or unwillingness of tenants to make contractually required payments. Market risk is the risk of declines in the value of stores due to changes in rental rates, interest rates or other market factors affecting the value of stores held by the Company. The Company has entered into interest rate swap agreements to manage a portion of its interest rate risk.
Exchange of Common Operating Partnership Units	Exchange of Common Operating Partnership Units Redemption of common Operating Partnership units for shares of common stock, when redeemed under the original provisions of the Operating Partnership agreement, are accounted for by reclassifying the underlying net book value of the units from noncontrolling interest to the Company’s equity.
Revenue and Expense Recognition	Revenue and Expense Recognition Rental revenues are recognized as earned based upon amounts that are currently due from tenants. Leases are generally on month-to-month terms. Prepaid rents are recognized on a straight-line basis over the term of the leases. Promotional discounts are recognized as a reduction to rental income over the promotional period. Late charges, administrative fees and merchandise sales are recognized as income when earned. Equity in earnings of unconsolidated real estate entities is recognized based on the Company's ownership interest in the earnings of each of the unconsolidated real estate entities. Interest income is recognized as earned. The Company's management fees are earned subject to the terms of the related management services agreements ("MSAs"). These MSAs provide that the Company will perform management services, which include leasing and operating the property and providing accounting, marketing, banking, maintenance and other services. These services are provided in exchange for monthly management fees, which are based on a percentage of revenues collected from stores owned by third parties and unconsolidated joint ventures. MSAs generally have original terms from three to five years, after which management services are provided on a month-to-month basis unless terminated. Management fees are due on the last day of each calendar month that management services are provided. The Company accounts for the management services provided to a customer as a single performance obligation which are rendered over time each month. The total amount of consideration from the contract is variable as it is based on monthly revenues, which are influenced by multiple factors, some of which are outside the Company's control. Therefore, the Company recognizes the revenue at the end of each month once the uncertainty is resolved. Due to the standardized terms of the MSAs, the Company accounts for all MSAs in a similar, consistent manner. Therefore, no disaggregated information relating to MSAs is presented. Property expenses, including utilities, property taxes, repairs and maintenance and other costs to manage the facilities are recognized as incurred. The Company accrues for property tax expense based upon invoice amounts and estimates. If these estimates are incorrect, the timing of expense recognition could be affected. Tenant reinsurance premiums are recognized as revenue over the period of insurance coverage. The Company records an unpaid claims liability at the end of each period based on existing unpaid claims and historical claims payment history. The unpaid claims liability represents an estimate of the ultimate cost to settle all unpaid claims as of each period end, including both reported but unpaid claims and claims that may have been incurred but have not been reported. The Company uses a third party claims administrator to adjust all tenant reinsurance claims received. The administrator evaluates each claim to determine the ultimate claim loss and includes an estimate for claims that may have been incurred but not reported. Annually, a third party actuary evaluates the adequacy of the unpaid claims liability. Prior year claim reserves are adjusted as experience develops or new information becomes known. The impact of such adjustments is included in the current period operations. The unpaid claims liability is not discounted to its present value. Each tenant chooses the amount of insurance coverage they want through the tenant reinsurance program. Tenants can purchase policies in amounts of 2,000 dollars to 10,000 dollars of insurance coverage in exchange for a monthly fee. As of December 31, 2018, the average insurance coverage for tenants was approximately 2,900 dollars. The Company’s exposure per claim is limited by the maximum amount of coverage chosen by each tenant. The Company purchases reinsurance for losses exceeding a set amount for any one event. The Company does not currently have any amounts recoverable under the reinsurance arrangements. For the years ended December 31, 2018, 2017 and 2016, the number of claims made were 7,870, 5,671 and 4,055, respectively. The following table presents information on the portion of the Company’s unpaid claims liability, which is included in other liabilities on the Company's consolidated balance sheets, that relates to tenant insurance for the periods indicated:
Advertising Costs	Advertising Costs The Company incurs advertising costs primarily attributable to digital and other advertising. These costs are expensed as incurred. The Company recognized $16,153, $14,410 and $12,867 in advertising expense for the years ended December 31, 2018, 2017 and 2016, respectively, which are included in property operating expenses on the Company’s consolidated statements of operations.
Income Taxes	Income Taxes The Company has elected to be treated as a REIT under Sections 856 through 860 of the Internal Revenue Code of 1986, as amended (the "Internal Revenue Code"). In order to maintain its qualification as a REIT, among other things, the Company is required to distribute at least 90% of its REIT taxable income to its stockholders and meet certain tests regarding the nature of its income and assets. As a REIT, the Company is not subject to federal income tax with respect to that portion of its income which meets certain criteria and is distributed annually to stockholders. The Company plans to continue to operate so that it meets the requirements for taxation as a REIT. Many of these requirements, however, are highly technical and complex. For any taxable year that the Company fails to qualify as a REIT and for which applicable statutory relief provisions did not apply, we would be taxed at the regular corporate rates on all of our taxable income for at least that year and the ensuing four years. The Company is subject to certain state and local taxes. Provision for such taxes has been included in income tax expense on the Company’s consolidated statements of operations. For the year ended December 31, 2018, 0% (unaudited) of all distributions to stockholders qualified as a return of capital. The Company has elected to treat its corporate subsidiary, Extra Space Management, Inc. (“ESMI”), as a taxable REIT subsidiary (“TRS”). In general, the Company’s TRS may perform additional services for tenants and may engage in any real estate or non-real estate related business. A TRS is subject to federal corporate income tax. ESM Reinsurance Limited, a wholly-owned subsidiary of ESMI, generates income from insurance premiums that are subject to federal corporate income tax and state insurance premiums tax. Deferred tax assets and liabilities are determined based on differences between financial reporting and tax bases of assets and liabilities. At December 31, 2018 and 2017, there were no material unrecognized tax benefits. Interest and penalties relating to uncertain tax positions will be recognized in income tax expense when incurred. As of December 31, 2018 and 2017, the Company had no interest or penalties related to uncertain tax provisions.
Stock-Based Compensation	Stock-Based Compensation The measurement and recognition of compensation expense for all share-based payment awards to employees and directors are based on estimated fair values. Awards granted are valued at fair value and any compensation expense is recognized over the service periods of each award.
Earnings Per Common Share	The Operating Partnership had $575,000 of its 3.125% Exchangeable Senior Notes due 2035 (the “2015 Notes”) issued and outstanding as of December 31, 2018. The 2015 Notes could potentially have a dilutive impact on the Company’s earnings per share calculations. The 2015 Notes are exchangeable by holders into shares of the Company’s common stock under certain circumstances per the terms of the indenture governing the 2015 Notes. The exchange price of the 2015 Notes was $92.80 per share as of December 31, 2018, and could change over time as described in the indenture. The Company has irrevocably agreed to pay only cash for the accreted principal amount of the 2015 Notes relative to its exchange obligations, but retained the right to satisfy the exchange obligation in excess of the accreted principal amount in cash and/or common stock. Though the Company has retained that right, Accounting Standards Codification (“ASC”) 260, “Earnings per Share,” requires an assumption that shares would be used to pay the exchange obligation in excess of the accreted principal amount, and requires that those shares be included in the Company’s calculation of weighted average common shares outstanding for the diluted earnings per share computation. As of December 31, 2018, the Company had repaid the principal and accrued interest of its Exchangeable Senior Notes due 2033 (the “2013 Notes”), and therefore, no shares underlying the 2013 Notes were included in the dilution calculation for 2018. For the years ended December 31, 2017 and 2016, 344,430 shares and 309,730 shares, respectively, related to the 2013 Notes were included in the computation for diluted earnings per share. For the years ended December 31, 2018, 2017 and 2016, no shares related to the 2015 Notes were included in the computation for diluted earnings per share as the exchange price exceeded the per share price of the Company’s common stock during this period. For the purposes of computing the diluted impact on earnings per share of the potential exchange of Series A Units for common shares upon redemption, where the Company has the option to redeem in cash or shares and where the Company has stated the positive intent and ability to settle at least $101,700 of the instrument in cash (or net settle a portion of the Series A Units against the related outstanding note receivable), only the amount of the instrument in excess of $101,700 is considered in the calculation of shares contingently issuable for the purposes of computing diluted earnings per share as allowed by ASC 260-10-45-46.
Recently Issued Accounting Standards	Recently Issued Accounting Standards In May 2014, the Financial Accounting Standards Board ("FASB") issued ASU 2014-9, “Revenue from Contracts with Customers,” ("Topic 606") which amends the guidance for revenue recognition to replace numerous, industry-specific requirements and converges areas under this topic with those of the International Financial Reporting Standards. Topic 606 outlines a five-step process for customer contract revenue recognition that focuses on transfer of control, as opposed to transfer of risk and rewards. The amendment also requires enhanced disclosures regarding the nature, amount, timing and uncertainty of revenues and cash flows from contracts with customers. Topic 606 became effective for annual and interim periods beginning after December 15, 2017. The Company determined that its property rental revenue and tenant reinsurance revenue are not subject to the guidance in Topic 606, as they qualify as lease contract and insurance contracts, which are excluded from its scope. The Company's management fee revenue is included in the scope of Topic 606, and revenue recognized under the standard does not differ materially from revenue recognized under previous guidance. The Company adopted the standard using the modified retrospective transition method as of January 1, 2018. The Company's adoption of Topic 606 did not result in a cumulative catch-up adjustment or any significant changes to financial statement line items. In February 2016, the FASB issued ASU 2016-02, "Leases (Topic 842)," which modifies the accounting for leases, intending to increase transparency and comparability of organizations by requiring balance sheet presentation of leased assets and increased financial statement disclosure of leasing arrangements. ASU 2016-02 will require entities to recognize a liability for their lease obligations and a corresponding asset representing the right to use the underlying asset over the lease term. Lease obligations are to be measured at the present value and accounted for using the effective interest method. The accounting for the leased asset will differ slightly depending on whether the agreement is deemed to be a financing or operating lease. For finance leases, the leased asset is depreciated on a straight-line basis and recorded separately from the interest expense in the statements of operations, resulting in higher expense in the earlier part of the lease term. For operating leases, the depreciation and interest expense components are combined, recognized evenly over the term of the lease, and presented as a reduction to operating income. ASU 2016-02 requires that assets and liabilities be presented or disclosed separately, and requires additional disclosure of certain qualitative and quantitative information related to these lease agreements. ASU 2016-02 is effective for annual periods beginning after December 15, 2018. The Company plans to adopt the standard using the modified retrospective approach as of January 1, 2019. The Company expects to elect the package of practical expedients upon adoption, which allows for the application of the standard solely to the transition period in 2019 but does not require application to prior fiscal comparative periods presented. The Company estimates that the cumulative catch-up adjustment recorded upon adoption will not have a significant impact on retained earnings. The primary impact is expected to be related to the Company's 23 operating ground leases and two corporate facility leases under which it serves as lessee. The Company estimates the lease assets and lease liabilities to be between $90,000 and $110,000 related to its operating leases upon the adoption of Topic 842. In October 2016, the FASB issued ASU 2016-18, "Statement of Cash Flows (Topic 230): Restricted Cash," which requires that a statement of cash flows explains the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. Therefore, amounts generally described as restricted cash and restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. This guidance is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. The Company adopted this guidance as of January 1, 2018, and now presents restricted cash along with cash and cash equivalents in its consolidated statements of cash flows. Prior periods have been reclassified to conform to the current year's presentation. In January 2017, the FASB issued ASU 2017-01, "Business Combinations (Topic 805) - Clarifying the Definition of a Business," which provides guidance on whether transactions should be accounted for as acquisitions or disposals of assets or businesses. Specifically, when substantially all of the fair value of the gross assets acquired (or disposed of) is concentrated in a single identifiable asset or a group of similar identifiable assets, the set is not a business. Additionally, ASU 2017-01 also provides other guidance providing a more robust framework to use in determining whether a set of assets and activities is a business. This guidance is effective for annual periods beginning after December 15, 2017. Early application of ASU 2017-01 is permitted for transactions for which the acquisition or disposition date occurs before the issuance date or effective date of the amendments, only when the transaction has not been reported in financial statements that have been issued. The Company adopted the guidance in ASU 2017-01 prospectively to new acquisitions beginning on January 1, 2017. The adoption of this guidance resulted in a decrease in acquisition related costs, as the Company's acquisition of operating stores are considered asset acquisitions rather than business combinations under ASU 2017-01, and such costs are capitalized under the new guidance. In August 2017, the FASB issued ASU 2017-12, "Derivatives and Hedging (Topic 815): Targeted Improvements for Accounting for Hedging Activities," which amends and simplifies existing guidance for the financial reporting of hedging relationships to allow companies to better portray the economic effects of risk management activities in their financial statements. ASU 2017-12 is effective for annual periods beginning after December 15, 2018, with early adoption permitted. The Company adopted this standard on January 1, 2018. The adoption of this standard did not have a material impact on the Company's financial statements. In August 2018, the FASB issued ASU 2018-15, "Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That is a Service Contract." ASU 2018-15 amends the accounting for implementation costs incurred in a hosting arrangement that is a service contract, and aligns them with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. ASU 2018-15 also requires that entities amortize the capitalized implementation costs over the term of the hosting arrangement. ASU 2018-15 is effective for annual periods beginning after December 15, 2020, with early adoption permitted, including early adoption in any interim period. The Company adopted this guidance on a prospective basis as of October 1, 2018. The adoption of this standard did not have a material impact on the Company's financial statements.
Convertible Debt	GAAP requires entities with convertible debt instruments that may be settled entirely or partially in cash upon conversion to separately account for the liability and equity components of the instrument in a manner that reflects the issuer’s economic interest cost. The Company therefore accounts for the liability and equity component of the 2015 Notes separately. The equity components are included in paid-in capital in stockholders’ equity in the consolidated balance sheets, and the value of the equity components are treated as original issue discount for purposes of accounting for the debt components. The discount is being amortized as interest expense over the remaining period of the debt through its first redemption date, October 1, 2020 for the 2015 Notes. The effective interest rate on the liability components of the 2015 Notes is 4.0%, which approximates the market rate of interest of similar debt without exchange features (i.e. nonconvertible debt) at the time of issuance.