INTERIM FINANCIAL INFORMATION	3 Months Ended
INTERIM FINANCIAL INFORMATION	Mar. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
INTERIM FINANCIAL INFORMATION	INTERIM FINANCIAL INFORMATION Business Group 1 Automotive, Inc., a Delaware corporation, is a leading operator in the automotive retailing industry with business activities in 15 states in the U.S., 33 towns in the U.K. and three states in Brazil. Group 1 Automotive, Inc. and its subsidiaries are collectively referred to as the “Company” in these Notes to Condensed Consolidated Financial Statements. Through its dealerships, the Company sells new and used cars and light trucks; arranges related vehicle financing; sells service and insurance contracts; provides automotive maintenance and repair services; and sells vehicle parts. As of March 31, 2021, the Company’s retail network consisted of 118 dealerships in the U.S., 49 dealerships in the U.K. and 16 dealerships in Brazil. The U.S. and Brazil are led by the President, U.S. and Brazilian Operations, and the U.K. is led by an Operations Director, each reporting directly to the Company's Chief Executive Officer. The President, U.S. and Brazilian Operations, and the U.K. Operations Director are responsible for the overall performance of their respective regions, as well as for overseeing field level management. The Company’s operating results are generally subject to seasonal variations, as well as changes in the economic environment. In the U.S., the Company generally experiences higher volumes of vehicle sales and service in the second and third calendar quarters of each year. In addition, in some regions of the U.S., vehicle purchases decline during the winter months due to inclement weather. In the U.K., the first and third quarters tend to be stronger, driven by the vehicle license plate change months of March and September. In Brazil, the first quarter is generally the weakest, driven by more consumer vacations and activities associated with Carnival, while the third and fourth quarters tend to be stronger. Other factors unrelated to seasonality, such as the COVID-19 pandemic, changes in economic conditions, manufacturer incentive programs, supply issues, seasonal weather events and/or changes in currency exchange rates may exaggerate seasonal or cause counter-seasonal fluctuations in the Company’s revenues and operating income. Basis of Presentation The accompanying Condensed Consolidated Financial Statements and notes thereto, have been prepared in accordance with U.S. GAAP for interim financial information and in accordance with the rules and regulations of the SEC. Accordingly, they do not include all of the information and notes required by U.S. GAAP for complete financial statements. Results for interim periods are not necessarily indicative of the results that can be expected for a full year and therefore should be read in conjunction with the Company’s audited Financial Statements and notes thereto included within the Company’s most recent Annual Report on Form 10-K. The accompanying Condensed Consolidated Financial Statements reflect the consolidated accounts of the parent company, Group 1 Automotive, Inc., and its subsidiaries, all of which are wholly owned. All intercompany balances and transactions have been eliminated in consolidation. Certain prior-period amounts have been reclassified to conform to current-period presentation. Specifically, the long-term liabilities associated with the Company’s interest rate swaps have been combined into the caption Other long-term liabilities in the Condensed Consolidated Balance Sheets. The reclassification within the Condensed Consolidated Balance Sheets had no effect on any subtotal in the statements. Additionally, repayments and borrowings on the Company’s real estate related and other debt have been combined within the captions Repayments on other debt and Borrowings on other debt, respectively, in the Condensed Consolidated Statements of Cash Flows. The reclassification within the Condensed Consolidated Statements of Cash Flows had no effect on any subtotal in the statements. Certain amounts in the Condensed Consolidated Financial Statements and the accompanying notes may not compute due to rounding. All computations have been calculated using unrounded amounts for all periods presented. These Condensed Consolidated Financial Statements reflect, in the opinion of management, all normal recurring adjustments necessary to fairly state, in all material respects, the Company’s financial position and results of operations for the periods presented. Use of Estimates The preparation of the Company’s financial statements in conformity with U.S. GAAP requires management to make certain estimates and assumptions. These estimates and assumptions affect the reported amounts of assets and liabilities, the disclosures of contingent assets and liabilities at the balance sheet date and the amounts of revenues and expenses recognized during the reporting period. Management analyzes the Company’s estimates based on historical experience and other assumptions that are believed to be reasonable under the circumstances, however, actual results could differ materially from such estimates. The significant estimates made by management in the accompanying Condensed Consolidated Financial Statements include, but are not limited to, inventory valuation adjustments, reserves for future chargebacks on finance, insurance and vehicle service contract fees, self-insured property and casualty insurance exposure, the fair value of assets acquired and liabilities assumed in business combinations, the valuation of goodwill and intangible franchise rights and reserves for potential litigation. Recent Accounting Pronouncements Reference Rate Reform In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting. The ASU provides optional expedients and exceptions for companies that have contracts, hedging relationships and other transactions that reference LIBOR or other reference rates expected to be discontinued because of reference rate reform. The optional expedients and exceptions are intended to ease the financial reporting burdens mainly related to contract modification accounting, hedge accounting and lease accounting. In January 2021, the FASB issued ASU 2021-01 which clarifies that certain optional expedients and exceptions in Topic 848 for contract modifications and hedge accounting apply to derivatives that are affected by the discounting transition. The guidance is effective for all entities as of March 12, 2020 and will apply through December 31, 2022. LIBOR is used as an interest rate “benchmark” in the majority of the Company’s floorplan notes payable, as well as its mortgages, other debt and lease contracts. Additionally, the Company’s derivative instruments are benchmarked to LIBOR. The Company will apply the relief described as its arrangements are modified and does not expect the adoption will have an impact on the Company’s consolidated financial statements due to the relief provided.