BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation: The accompanying Condensed Consolidated Financial Statements include the accounts of Stericycle, Inc. and its subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. The Company's Condensed Consolidated Financial Statements were prepared in accordance with United States’ Generally Accepted Accounting Principles (“U.S. GAAP”) and include the assets, liabilities, revenues and expenses of all wholly-owned subsidiaries and majority-owned subsidiaries over which the Company exercises control. Outside shareholders' interests in subsidiaries are shown on the Condensed Consolidated Financial Statements as “Noncontrolling interests." The accompanying unaudited Condensed Consolidated Financial Statements as of September 30, 2018 and for the three and nine months ended September 30, 2018 and 2017 have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) for interim reporting and, therefore, do not include all information and footnote disclosures normally included in audited financial statements prepared in conformity with U.S. GAAP. However, in the opinion of management, all adjustments, consisting of normal recurring adjustments, necessary to present fairly the results of operations, financial position and cash flows have been made. These Condensed Consolidated Financial Statements should be read in conjunction with the consolidated financial statements and notes thereto included in the Annual Report Form 10-K for the year ended December 31, 2017 (the “2017 Form 10-K”). The results of operations for any interim period are not necessarily indicative of the results of operations to be expected for the full year.
Use of Estimates	Use of Estimates: The preparation of financial statements in conformity with U.S. GAAP requires us to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Some areas where we make estimates include our allowance for doubtful accounts, credit memo reserve, accrued employee health and welfare benefits, environmental liabilities, stock-based compensation expense, income tax liabilities, accrued auto and workers’ compensation insurance claims, intangible asset valuations and goodwill impairment. Such estimates are based on historical trends and on various other assumptions that are believed to be reasonable under the circumstances. Actual results could differ from our estimates. The following information updates the description of significant accounting policies contained in Note 1 – Basis of Presentation and Summary of Significant Accounting Policies in our Consolidated Financial Statements included in the Company’s 2017 Form 10-K.
Highly Inflationary Economy	Highly Inflationary Economy: Effective July 1, 2018, as a result of the three-year cumulative inflation exceeding 100% and under the guidance given in ASC 830 “Foreign Currency Matters”, Argentina was classified as a highly inflationary economy. Accordingly, the Company recognized, in Other expense, net, a foreign exchange loss of $5.0 million arising from the remeasurement of our Argentinian peso denominated net monetary assets during the three months ended September 30, 2018. Nonmonetary assets, liabilities and related expenses are measured using historical exchange rates and do not fluctuate with changes in the local exchange rate. As of September 30, 2018, our Argentinian peso denominated net monetary assets amounted to approximately 430 million Argentinian pesos or $10.5 million.
New Accounting Standards	Adoption of New Accounting Standards: Revenue Recognition Effective January 1, 2018, the Company adopted ASU No. 2014-19, “Revenue from Contracts with Customers” (“ASC 606”) using the modified retrospective method for all contracts that were not completed as of the date of adoption. The results of operations for reported periods after January 1, 2018 are presented under this amended guidance, while prior period amounts are reported in accordance with ASC 605 Revenue Recognition, which is also referred to herein as “legacy U.S. GAAP” or historical guidance. The impact of adopting ASC 606 relates to (i) the deferral of certain costs associated with obtaining contracts with customers, which were previously expensed as incurred, but under the new guidance are capitalized as Other current assets and Other assets and amortized to Selling, general and administrative expenses (“SG&A”) over the expected period of benefit to be received, (ii) the write off of deferred installation costs, which were capitalized as Prepaid expenses under legacy U.S. GAAP but are expensed as incurred under ASC 606 and (iii) an increase in Deferred income tax liabilities with respect to the tax impact associated with these items. We recognized a net increase to Retained earnings of $13.0 million as of January 1, 2018 for the cumulative effect of adopting ASC 606. This was comprised of $22.9 million associated with the capitalization of contract acquisition costs offset by a $4.9 million write off of deferred installation costs and $5.0 million to recognize Deferred income tax liabilities. The impact to Income from operations from the adoption of ASC 606 was a decrease in SG&A of $1.3 million and $7.6 million for the three and nine months ended September 30, 2018, respectively. Definition of a Business Effective January 1, 2018, the Company adopted ASU No. 2017-01, “Clarifying the Definition of a Business” (“ASU 2017-01”), which provides guidance to clarify the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The amendments in ASU 2017-01 provide a screen to determine when an integrated set of assets and activities (collectively referred to as a “set”) is not a business. The screen requires that 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. This screen reduces the number of transactions that need to be further evaluated. If the screen is not met, the amendments require that to be considered a business, a set must include, at a minimum, an input and a substantive process that together significantly contribute to the ability to create output and remove the evaluation of whether a market participant could replace the missing elements. The guidance in ASU 2017-01 was applied in evaluating the transactions discussed in Note 3 – Acquisitions, but did not otherwise impact the accompanying Condensed Consolidated Financial Statements. Due to the number of acquisitions the Company completes in any year, there may be instances where the acquisition will be determined to be an acquisition of assets instead of a business. The Company believes this will be a minority of the acquisitions completed in any year and that there will not be a material impact to our financial statements. Intra-Entity Transfers of Assets Other Than Inventory On January 1, 2018, the Company adopted the guidance in ASU No. 2016-16, “Intra-Entity Transfers of Assets Other Than Inventory” (“ASU 2016-16”). ASU 2016-16 requires the income tax consequences of an intra-entity transfer of an asset other than inventory to be recognized when the transfer occurs, instead of when the asset is sold to an outside party. The Company’s adoption of ASU 2016-16 did not have an impact on the accompanying Condensed Consolidated Financial Statements. Compensation – Stock Compensation On January 1, 2018, the Company adopted ASU No. 2017-09, “Compensation – Stock Compensation (Topic 718): Scope of Modification Accounting” (“ASU 2017-09”). ASU 2017-09 clarifies when to account for a change to the terms or conditions of a share-based payment award as a modification. Under the new guidance, modification accounting is required only if the fair value, the vesting conditions, or the classification of the award (as equity or liability) changes as a result of the change in terms or conditions. The Company’s adoption of ASU 2017-09 did not have an impact on the accompanying Condensed Consolidated Financial Statements. Accounting Standards Issued But Not Yet Adopted Leases In February 2016, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2016-02, “Leases” (Topic 842) (“ASU 2016-02”). This guidance will require lessees to record a right-of-use asset and lease liability on the balance sheet for all leases with terms of more than 12 months. ASU 2016-02 also requires certain quantitative and qualitative disclosures. Accounting guidance for lessors is largely unchanged. The guidance must be applied at one of two application dates using a modified retrospective method. A cumulative effect adjustment to retained earnings will be recorded at the beginning of the earliest period presented or the effective date depending on the application date selected. This ASU is effective for the Company beginning January 1, 2019, and the Company expects to apply the standard’s transition provisions, and record the cumulative adjustment as of that date. In addition, the Company expects to avail itself of the package of practical expedients allowing the Company not to reassess (a) whether any expired or existing contact contains a lease, (b) the lease classification of any expired or existing leases, and (c) the initial direct costs for any existing leases. The Company previously engaged a third party service provider to assist in its implementation of the new leases standard and is continuing to gather, document and analyze lease agreements related to this ASU and anticipates recognizing material right-of-use assets and related liabilities upon adoption. The Company has also selected and is advancing the process of implementing a software package, including user acceptance testing and training, to manage and account for leases under the new guidance. Additionally, the Company is continuing to monitor industry activities and any additional guidance provided by or changed by regulators, standards setters, or the accounting profession to adjust the Company’s assessment and implementation plans accordingly. Derivatives and Hedging In August 2017, the FASB issued ASU No. 2017-12, “Derivatives and Hedging” (Topic 815): Targeted Improvements to Accounting for Hedging Activities (“ASU 2017-12”). ASU 2017-12 amends the hedge accounting recognition and presentation requirements with the objective of improving the financial reporting of hedging relationships to better portray the economic results of an entity’s risk management activities in its financial statements and enhance the transparency and understandability of hedge transactions. In addition, ASU 2017-12 makes improvements to simplify the application of the hedge accounting guidance. ASU 2017-12 is effective for us on January 1, 2019, with early adoption permitted. The Company does not expect the adoption to materially impact our Condensed Consolidated Financial Statements. Financial Instrument Credit Losses In June 2016, the FASB issued ASU No. 2016-13, “Financial Instruments – Credit Losses” (“ASU 2016-13”) associated with the measurement of credit losses on financial instruments. ASU 2016-13 replaces the current incurred loss impairment methodology of recognizing credit losses when a loss is probable, with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to assess credit loss estimates. The amended guidance is effective for us on January 1, 2020, with early adoption permitted beginning January 1, 2019. We are evaluating the impact on our Condensed Consolidated Financial Statements. Stranded Tax Effects In February 2018, the FASB issued ASU 2018-02, “Income Statement - Reporting Comprehensive Income: Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income” (“ASU 2018-02”), which allows for stranded tax effects in accumulated other comprehensive income resulting from the U.S. Tax Cuts and Jobs Act of 2017 (the “Act”) to be reclassified to retained earnings. ASU 2018-02 is effective for interim and annual periods beginning after December 15, 2018. We will adopt ASU 2018-02 on January 1, 2019. The adoption of ASU 2018-02 will result in a reclassification between accumulated other comprehensive income and retained earnings, and will have no impact on our results of operations or financial position. Implementation Costs Incurred in a Cloud Computing Arrangement In August 2018, the FASB issued ASU 2018-15, “Goodwill and Other Intangibles- Internal Use Software – Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract” (“ASU 2018-15”). ASU 2018-15 aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs for internal-use software. The accounting for any hosting contract is unchanged. ASU 2018-15 is effective for us on January 1, 2020 with early adoption permitted, including adoption in any interim period. We are evaluating the impact on our Condensed Consolidated Financial Statements.
Revenue	In accordance with ASC 606, revenue is recognized when a customer obtains control of promised goods or services. The amount of revenue recognized reflects the consideration to which the Company expects to be entitled to receive in exchange for these goods or services. Revenue is recognized net of revenue-based taxes assessed by governmental authorities. The Company provides regulated and compliance services, which include the collection and processing of regulated and specialized waste for disposal, the collection of personal and confidential information for secure destruction, recall and returns (“Expert Solutions”) and communication services. The associated activities for each of these are a series of distinct services that are substantially the same and have the same pattern of transfer over time; therefore, the respective services are treated as a single performance obligation. The Company recognizes revenue by applying the right to invoice practical expedient as our right to consideration corresponds directly to the value provided to the customer for performance to date. Revenues for our Medical Waste Solutions and Secure Information Destruction Services are recognized upon waste collection. Our Compliance Solution revenues are recognized over the contractual service period. Revenues from Hazardous Waste Solutions and Manufacturing and Industrial Services are recognized at the time the waste is received by a facility with an appropriate permit, either our processing facility or a third party. Revenues from Communication Services and Expert Solutions are recorded as the services are performed.
Accounts Receivable	Accounts Receivable Accounts receivable are recorded when invoiced or when goods or services are provided. The carrying value of our receivables is presented net of an allowance for doubtful accounts. We estimate our allowance for doubtful accounts based on past collection history and specific risks identified among uncollected amounts. If events or changes in circumstances indicate that specific receivable balances may be impaired, further consideration is given to the collectability of those balances and the allowance is adjusted accordingly. Past-due receivable balances are written off when our collection efforts have been exhausted.
Contract Liabilities	Contract Liabilities We record a contract liability when cash payments are received or due in advance of our services being performed. The majority of the contract liability is classified as current in Other current liabilities on the Condensed Consolidated Balance Sheets since amounts are generally earned in the subsequent quarter. The contract liability at September 30, 2018, June 30, 2018, and December 31, 2017 was $15.5 million, $17.4 million, and $17.9 million, respectively.
Contract Acquisition Costs	Contract Acquisition Costs Our incremental direct costs of obtaining a contract, which consist primarily of sales incentives, are deferred and amortized to SG&A over the estimated period of benefit to be received from the cost, over a weighted average period of 6.3 years. We had $7.7 million and $22.8 million of contract acquisition costs, related to deferred sales incentives included in Other current assets and Other assets, respectively, on the Condensed Consolidated Balance Sheet as of September 30, 2018. During the three and nine months ended September 30, 2018, we amortized $1.8 million and $5.0 million, respectively, of deferred sales incentives to SG&A.

Disclosure of accounting policy for trade and other accounts receivable, and finance, loan and lease receivables, including those classified as held for investment and held for sale. This disclosure may include (1) the basis at which such receivables are carried in the entity's statements of financial position (2) how the level of the valuation allowance for receivables is determined (3) when impairments, charge-offs or recoveries are recognized for such receivables (4) the treatment of origination fees and costs, including the amortization method for net deferred fees or costs (5) the treatment of any premiums or discounts or unearned income (6) the entity's income recognition policies for such receivables, including those that are impaired, past due or placed on nonaccrual status and (7) the treatment of foreclosures or repossessions (8) the nature and amount of any guarantees to repurchase receivables.