Commitments and Contingencies	9 Months Ended
Sep. 30, 2017
Commitments and Contingencies [Abstract]
Commitments and Contingencies	8. Commitments and Contingencies Data Security Incident In April 2017, our information security team detected unauthorized activity on the network that supports payment processing for our restaurants, and immediately began an investigation with the help of leading computer security firms. We also self-reported the issue to payment card processors and law enforcement. Our investigation detected malware designed to access payment card data from cards used at point-of-sale devices at most Chipotle restaurants, primarily in the period from March 24, 2017 through April 18, 2017. The malware searched for track data, which may include cardholder name, card number, expiration date, and internal verification codes; however, no other customer information was affected. We have removed the malware from our systems and continue to evaluate ways to enhance our security measures. We expect that substantially all of our investigation costs will be covered by insurance; however, we may incur legal expenses in excess of our insurance coverage limits associated with the data security incident in future periods. We will recognize these expenses as services are received. During the three months ended September 30, 2017, we recorded an expense of $30,000 ($18,234 after tax), or $0.64 per basic and diluted earnings per share, as an estimate of potential liabilities associated with anticipated claims and assessments by payment card networks in connection with the data security incident. We may ultimately be subject to liabilities greater than or less than the amount accrued. The expense is recorded in general and administrative expenses in our condensed consolidated statement of income and a corresponding liability in accrued liabilities on our condensed consolidated balance sheet. Litigation Arising from Security Incident On May 4, 2017, Bellwether Community Credit Union filed a purported class action complaint in the United States District Court for the District of Colorado alleging that we negligently failed to provide adequate security to protect the payment card information of customers of the plaintiffs and those of other similarly situated credit unions, banks and other financial institutions alleged to be part of the putative class, causing those institutions to suffer financial losses. The complaint also claims we were negligent per se based on alleged violations of Section 5 of the Federal Trade Commission Act and similar state laws. The plaintiff seeks monetary damages, injunctive relief and attorneys’ fees. On May 26, 2017, Alcoa Community Credit Union filed a purported class action complaint in the U. S. District Court for the District of Colorado making substantially the same allegations as the Bellwether complaint and seeking substantially the same relief. The Bellwether and Alcoa cases have been consolidated and will proceed as a single action. On June 9, 2017, Todd Gordon filed a purported class action complaint in the U. S. District Court for the District of Colorado alleging that we negligently failed to provide adequate security to protect the payment card information of the plaintiff and other similarly situated customers alleged to be part of the putative class, causing such customers to suffer financial losses. The complaint also claims we were negligent per se based on alleged violations of Section 5 of the Federal Trade Commission Act and similar state laws, and also alleges breach of contract, unjust enrichment, and violations of the Arizona Consumer Fraud Act. Additionally, on August 21, 2017, Greg Lawson and Judy Conard filed a purported class action complaint in the U. S. District Court for the District of Colorado making allegations substantially similar to those in the Gordon complaint, and stating substantially similar claims as well as claims under the Colorado Consumer Protection Act. The plaintiffs in the Gordon case and the Lawson and Conard case have notified the court of their agreement to consolidate their cases and file an amended consolidated complaint for the consolidated matter. We intend to vigorously defend each of the aforementioned cases, but it is not possible at this time to reasonably estimate the outcome of or any potential liability from these cases. Although certain fees and costs associated with the data security incident and the aforementioned litigation to date have been paid or reimbursed by our cyber liability insurer, the ultimate amount of liabilities arising from the litigation may be in excess of the limits of our applicable insurance coverage. Receipt of Grand Jury Subpoenas On January 28, 2016, we were served with a Federal Grand Jury Subpoena from the U.S. District Court for the Central District of California in connection with an official criminal investigation being conducted by the U.S. Attorney’s Office for the Central District of California, in conjunction with the U.S. Food and Drug Administration’s Office of Criminal Investigations. The subpoena requires the production of documents and information related to company-wide food safety matters dating back to January 1, 2013. We received a follow-up subpoena on July 19, 2017 requesting information related to illness incidents associated with a single Chipotle restaurant in Sterling, Virginia. We intend to continue to fully cooperate in the investigation. It is not possible at this time to determine whether we will incur, or to reasonably estimate the amount of, any fines or penalties in connection with the investigation pursuant to which the subpoena was issued. Shareholder Derivative Actions On April 6, 2016, Uri Skorski filed a shareholder derivative action in Colorado state court in Denver, Colorado, alleging that our Board of Directors and officers breached their fiduciary duties in connection with our alleged failure to disclose material information about our food safety policies and procedures, and also alleging that our Board of Directors and officers breached their fiduciary duties in connection with allegedly excessive compensation awarded from 2011 to 2015 under our stock incentive plan. On April 14, 2016, Mark Arnold and Zachary Arata filed a shareholder derivative action in Colorado state court in Denver, Colorado, making largely the same allegations as the Skorski complaint. On May 26, 2016, the court issued an order consolidating the Skorski and Arnold/Arata actions into a single case. On August 8, 2016, Sean Gubricky filed a shareholder derivative action in the U.S. District Court for the District of Colorado, alleging that our Board of Directors and certain officers failed to institute proper food safety controls and policies, issued materially false and misleading statements in violation of federal securities laws, and otherwise breached their fiduciary duties to us. On September 1, 2016, Ross Weintraub filed a shareholder derivative action in Colorado state court in Denver, Colorado, making largely the same allegations as the Gubricky complaint. On March 27, 2017, the Weintraub case was consolidated with the Skorski and Arnold/Arata action into a single case. On December 27, 2016, Cyrus Lashkari filed a shareholder derivative action in the U.S. District Court for the District of Colorado, making largely the same allegations as the foregoing shareholder derivative complaints. Each of these actions purports to state a claim for damages on our behalf, and is based on statements in our SEC filings and related public disclosures, as well as media reports and company records. We have reached an agreement to settle the foregoing actions, and the proposed settlement has been preliminarily approved by the U.S. District Court for the District of Colorado. On July 28, 2017, Mark Blau filed a shareholder derivative action in the U.S. District Court for the District of Colorado, making allegations similar to those of the several shareholder derivative actions described above, and adding further allegations related to the Board’s investigation of the foregoing matters, as well as customer illnesses and operational issues associated with two Chipotle restaurants in July 2017. The action purports to state claims for damages on our behalf, and is based on statements in our SEC filings and related public disclosures, as well as media reports and company records. We intend to defend this case vigorously, but it is not possible at this time to reasonably estimate the outcome of or any potential liability from the case. Shareholder Class Actions On January 8, 2016, Susie Ong filed a complaint in the U.S. District Court for the Southern District of New York on behalf of a purported class of purchasers of shares of our common stock between February 4, 2015 and January 5, 2016. The complaint purports to state claims against us, each of the co-Chief Executive Officers serving during the claimed class period and the Chief Financial Officer under Sections 10(b) and 20(a) of the Exchange Act and related rules, based on our alleged failure during the claimed class period to disclose material information about our quality controls and safeguards in relation to consumer and employee health. The complaint asserts that those failures and related public statements were false and misleading and that, as a result, the market price of our stock was artificially inflated during the claimed class period. The complaint seeks damages on behalf of the purported class in an unspecified amount, interest, and an award of reasonable attorneys’ fees, expert fees and other costs. On March 8, 2017, the court granted our motion to dismiss the complaint, with leave to amend. The plaintiff filed an amended complaint on April 7, 2017. Additionally, on July 20, 2017, Elizabeth Kelly filed a complaint in the U.S. District Court for the District of Colorado on behalf of a purported class of purchasers of shares of our common stock between February 5, 2016 and July 19, 2017, with claims and factual allegations similar to the Ong complaint, based primarily on media reports regarding illnesses associated with a Chipotle restaurant in Sterling, Virginia. We intend to defend these cases vigorously, but it is not possible at this time to reasonably estimate the outcome of or any potential liability from the cases. Miscellaneous We are involved in various other claims and legal actions that arise in the ordinary course of business. We do not believe that the ultimate resolution of these actions will have a material adverse effect on our financial position, results of operations, liquidity or capital resources. However, a significant increase in the number of these claims, or one or more successful claims under which we incur greater liabilities than we currently anticipate, could materially and adversely affect our business, financial condition, results of operations and cash flows.

8. Commitments and Contingencies

Data Security Incident

In April 2017, our information security team detected unauthorized activity on the network that supports payment processing for our restaurants, and immediately began an investigation with the help of leading computer security firms. We also self-reported the issue to payment card processors and law enforcement. Our investigation detected malware designed to access payment card data from cards used at point-of-sale devices at most Chipotle restaurants, primarily in the period from March 24, 2017 through April 18, 2017. The malware searched for track data, which may include cardholder name, card number, expiration date, and internal verification codes; however, no other customer information was affected. We have removed the malware from our systems and continue to evaluate ways to enhance our security measures. We expect that substantially all of our investigation costs will be covered by insurance; however, we may incur legal expenses in excess of our insurance coverage limits associated with the data security incident in future periods. We will recognize these expenses as services are received.

During the three months ended September 30, 2017, we recorded an expense of $30,000 ($18,234 after tax), or $0.64 per basic and diluted earnings per share, as an estimate of potential liabilities associated with anticipated claims and assessments by payment card networks in connection with the data security incident. We may ultimately be subject to liabilities greater than or less than the amount accrued. The expense is recorded in general and administrative expenses in our condensed consolidated statement of income and a corresponding liability in accrued liabilities on our condensed consolidated balance sheet.

Litigation Arising from Security Incident

On May 4, 2017, Bellwether Community Credit Union filed a purported class action complaint in the United States District Court for the District of Colorado alleging that we negligently failed to provide adequate security to protect the payment card information of customers of the plaintiffs and those of other similarly situated credit unions, banks and other financial institutions alleged to be part of the putative class, causing those institutions to suffer financial losses. The complaint also claims we were negligent per se based on alleged violations of Section 5 of the Federal Trade Commission Act and similar state laws. The plaintiff seeks monetary damages, injunctive relief and attorneys’ fees. On May 26, 2017, Alcoa Community Credit Union filed a purported class action complaint in the U. S. District Court for the District of Colorado making substantially the same allegations as the Bellwether complaint and seeking substantially the same relief. The Bellwether and Alcoa cases have been consolidated and will proceed as a single action.

On June 9, 2017, Todd Gordon filed a purported class action complaint in the U. S. District Court for the District of Colorado alleging that we negligently failed to provide adequate security to protect the payment card information of the plaintiff and other similarly situated customers alleged to be part of the putative class, causing such customers to suffer financial losses. The complaint also claims we were negligent per se based on alleged violations of Section 5 of the Federal Trade Commission Act and similar state laws, and also alleges breach of contract, unjust enrichment, and violations of the Arizona Consumer Fraud Act. Additionally, on August 21, 2017, Greg Lawson and Judy Conard filed a purported class action complaint in the U. S. District Court for the District of Colorado making allegations substantially similar to those in the Gordon complaint, and stating substantially similar claims as well as claims under the Colorado Consumer Protection Act. The plaintiffs in the Gordon case and the Lawson and Conard case have notified the court of their agreement to consolidate their cases and file an amended consolidated complaint for the consolidated matter.

We intend to vigorously defend each of the aforementioned cases, but it is not possible at this time to reasonably estimate the outcome of or any potential liability from these cases. Although certain fees and costs associated with the data security incident and the aforementioned litigation to date have been paid or reimbursed by our cyber liability insurer, the ultimate amount of liabilities arising from the litigation may be in excess of the limits of our applicable insurance coverage.

Receipt of Grand Jury Subpoenas

On January 28, 2016, we were served with a Federal Grand Jury Subpoena from the U.S. District Court for the Central District of California in connection with an official criminal investigation being conducted by the U.S. Attorney’s Office for the Central District of California, in conjunction with the U.S. Food and Drug Administration’s Office of Criminal Investigations. The subpoena requires the production of documents and information related to company-wide food safety matters dating back to January 1, 2013. We received a follow-up subpoena on July 19, 2017 requesting information related to illness incidents associated with a single Chipotle restaurant in Sterling, Virginia. We intend to continue to fully cooperate in the investigation. It is not possible at this time to determine whether we will incur, or to reasonably estimate the amount of, any fines or penalties in connection with the investigation pursuant to which the subpoena was issued.

Shareholder Derivative Actions

On April 6, 2016, Uri Skorski filed a shareholder derivative action in Colorado state court in Denver, Colorado, alleging that our Board of Directors and officers breached their fiduciary duties in connection with our alleged failure to disclose material information about our food safety policies and procedures, and also alleging that our Board of Directors and officers breached their fiduciary duties in connection with allegedly excessive compensation awarded from 2011 to 2015 under our stock incentive plan. On April 14, 2016, Mark Arnold and Zachary Arata filed a shareholder derivative action in Colorado state court in Denver, Colorado, making largely the same allegations as the Skorski complaint. On May 26, 2016, the court issued an order consolidating the Skorski and Arnold/Arata actions into a single case. On August 8, 2016, Sean Gubricky filed a shareholder derivative action in the U.S. District Court for the District of Colorado, alleging that our Board of Directors and certain officers failed to institute proper food safety controls and policies, issued materially false and misleading statements in violation of federal securities laws, and otherwise breached their fiduciary duties to us. On September 1, 2016, Ross Weintraub filed a shareholder derivative action in Colorado state court in Denver, Colorado, making largely the same allegations as the Gubricky complaint. On March 27, 2017, the Weintraub case was consolidated with the Skorski and Arnold/Arata action into a single case. On December 27, 2016, Cyrus Lashkari filed a shareholder derivative action in the U.S. District Court for the District of Colorado, making largely the same allegations as the foregoing shareholder derivative complaints. Each of these actions purports to state a claim for damages on our behalf, and is based on statements in our SEC filings and related public disclosures, as well as media reports and company records. We have reached an agreement to settle the foregoing actions, and the proposed settlement has been preliminarily approved by the U.S. District Court for the District of Colorado.

On July 28, 2017, Mark Blau filed a shareholder derivative action in the U.S. District Court for the District of Colorado, making allegations similar to those of the several shareholder derivative actions described above, and adding further allegations related to the Board’s investigation of the foregoing matters, as well as customer illnesses and operational issues associated with two Chipotle restaurants in July 2017. The action purports to state claims for damages on our behalf, and is based on statements in our SEC filings and related public disclosures, as well as media reports and company records. We intend to defend this case vigorously, but it is not possible at this time to reasonably estimate the outcome of or any potential liability from the case.

Shareholder Class Actions

On January 8, 2016, Susie Ong filed a complaint in the U.S. District Court for the Southern District of New York on behalf of a purported class of purchasers of shares of our common stock between February 4, 2015 and January 5, 2016. The complaint purports to state claims against us, each of the co-Chief Executive Officers serving during the claimed class period and the Chief Financial Officer under Sections 10(b) and 20(a) of the Exchange Act and related rules, based on our alleged failure during the claimed class period to disclose material information about our quality controls and safeguards in relation to consumer and employee health. The complaint asserts that those failures and related public statements were false and misleading and that, as a result, the market price of our stock was artificially inflated during the claimed class period. The complaint seeks damages on behalf of the purported class in an unspecified amount, interest, and an award of reasonable attorneys’ fees, expert fees and other costs. On March 8, 2017, the court granted our motion to dismiss the complaint, with leave to amend. The plaintiff filed an amended complaint on April 7, 2017. Additionally, on July 20, 2017, Elizabeth Kelly filed a complaint in the U.S. District Court for the District of Colorado on behalf of a purported class of purchasers of shares of our common stock between February 5, 2016 and July 19, 2017, with claims and factual allegations similar to the Ong complaint, based primarily on media reports regarding illnesses associated with a Chipotle restaurant in Sterling, Virginia. We intend to defend these cases vigorously, but it is not possible at this time to reasonably estimate the outcome of or any potential liability from the cases.

Miscellaneous

We are involved in various other claims and legal actions that arise in the ordinary course of business. We do not believe that the ultimate resolution of these actions will have a material adverse effect on our financial position, results of operations, liquidity or capital resources. However, a significant increase in the number of these claims, or one or more successful claims under which we incur greater liabilities than we currently anticipate, could materially and adversely affect our business, financial condition, results of operations and cash flows.