Interim Financial Information Interim Financial Information (Policies)	3 Months Ended
Mar. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
New Accounting Pronouncements, Policy [Policy Text Block]	Recently Adopted Accounting Pronouncements In July 2015, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2015-11, Inventory (Topic 330): Simplifying the Measurement of Inventory. The amendments in the accounting standard replace the lower of cost or market test with a lower of cost and net realizable value test. The amendments in this ASU should be applied prospectively and are effective for interim and annual periods beginning after December 15, 2016. The Company adopted ASU 2015-11 during the first quarter of 2017. The adoption of this ASU did not materially impact its consolidated financial statements or results of operations. In March 2016, the FASB issued ASU 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. The amendment addresses several aspects of the accounting for share-based payment award transactions, including: income tax consequences; classification of awards as either equity or liabilities; and classification on the statement of cash flows. The amendments in this ASU should be applied prospectively and are effective for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years. The Company adopted ASU 2016-09 during the first quarter of 2017. The adoption of this ASU did not materially impact its consolidated financial statements or results of operations. Recently Issued Accounting Pronouncements In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606) that amends the accounting guidance on revenue recognition. The amendments in this ASU are intended to provide a framework for addressing revenue issues, improve comparability of revenue recognition practices, and improve disclosure requirements. This ASU sets forth a five-step model for determining when and how revenue is recognized. Under the model, an entity will be required to recognize revenue to depict the transfer of goods or services to a customer at an amount reflecting the consideration it expects to receive in exchange for those goods or services. The amendments in this accounting standard update are effective for interim and annual reporting periods beginning after December 15, 2017. The standard can be adopted either retrospectively to each reporting period presented or as a cumulative effect adjustment as of the date of adoption. To assess the impact of the ASU, the Company established an internal implementation team to review its current accounting policies and practices, identify all material revenue streams, assess the impact of the ASU on its material revenue streams and identify potential differences with current policies and practices. The Company’s internal implementation team has substantially completed its initial review of the likely impacts that the application of the amendments in this ASU will have on its consolidated financial statements. The team has initially identified the Company’s material revenue streams to be the sale of new and used vehicles; arrangement of associated vehicle financing; the sale of service and insurance contracts; the performance of vehicle maintenance and repair services; and the sale of vehicle parts. The team has begun its review of a sample of associated contracts and other related documents, but currently, has not quantified an estimated impact of changes, if any, to its current revenue recognition policies and practices. The Company’s implementation team is in the preliminary stages of evaluating the additional disclosure requirements of the ASU, as well as the change, if any, to the Company’s underlying accounting and financial reporting systems and processes necessary to support the recognition and disclosure requirements. The Company expects to identify and implement the necessary changes, if any, during 2017. At this time, based on this review, the Company does not expect the adoption to materially impact its consolidated financial statements. The Company currently expects to adopt the amendments of this ASU during the first fiscal quarter of 2018, as a cumulative effect adjustment as of the date of adoption, but will not make a final decision on the adoption method until later in 2017. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842). The amendments in this ASU relate to the accounting for leasing transactions. This standard requires a lessee to record on the balance sheet the assets and liabilities for the rights and obligations created by leases with lease terms of more than 12 months. In addition, this standard requires both lessees and lessors to disclose certain key information about lease transactions. This standard will be effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. The Company is in the process of evaluating the impact that adoption will have on its consolidated balance sheet and statement of income. However, the Company expects that the adoption of the provisions of the ASU will have a significant impact on its consolidated balance sheet, as currently approximately half of its real estate is rented, not owned, via operating leases. Adoption of this ASU is required to be done using a modified retrospective approach. In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326) Measurement of Credit Losses on Financial Instruments. The amendment 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 standard will be effective for fiscal years beginning after December 15, 2019, with early adoption permitted for periods after December 15, 2018. The Company is currently evaluating the impact that the adoption of the provisions of the ASU will have on its consolidated financial statements or results of operations. In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments. The amendment addresses several specific cash flow issues with the objective of reducing the diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. The standard will be effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. The Company is currently evaluating the impact that the adoption of the provisions of the ASU will have on its consolidated financial statements. In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash, a consensus of the FASB Emerging Issues Task Force ("EITF"). The amendments require that a statement of cash flows explain 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. The amendments in this ASU do not provide a definition of restricted cash or restricted cash equivalents. The standard will be effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. The Company is currently evaluating the impact that the adoption of the provisions of the ASU will have on its consolidated financial statements. In January 2017, the FASB issued ASU 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business. The amendments in this update clarify the definition of a business in order to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The amendments in this ASU should be applied prospectively and are effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years, with early adoption permitted. The Company is currently evaluating the impact on its consolidated financial statements as it will depend on the facts and circumstances of any specific future transactions. In January 2017, the FASB issued ASU 2017-03, Accounting Changes and Error Corrections (Topic 250) and Investments-Equity Method and Joint Ventures (Topic 323): Amendments to SEC Paragraphs Pursuant to Staff Announcements at the September 22, 2016 and November 17, 2016 EITF Meetings. The amendments in this update require the disclosure of the impact that a recently issued ASU will have on the financial statements of a registrant when such standards are to be adopted in a future period. The SEC staff view that a registrant should evaluate ASU's that have not yet been adopted to determine the appropriate financial statement disclosures about the potential material effects of those ASU's on the financial statements when adopted. The Company does not expect the amendments in this ASU to materially impact its consolidated financial statements. In January 2017, the FASB issued ASU 2017-04, Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment. The amendment eliminates the requirement to calculate the implied fair value of goodwill to measure a goodwill impairment charge. Instead, entities will record an impairment charge based on the excess of a reporting unit's carrying amount over its fair value. The amendments in this update should be applied prospectively and are effective for interim and annual periods beginning after December 15, 2019. Earlier application is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. The Company is currently evaluating the impact that the adoption of the provisions of the ASU will have on its consolidated financial statements.
Basis of Presentation [Text Block]	Basis of Presentation The accompanying unaudited condensed Consolidated Financial Statements have been prepared in accordance with accounting principles generally accepted in the U.S. ("U.S. GAAP") for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. In the opinion of management, all adjustments of a normal and recurring nature considered necessary for a fair presentation have been included in the accompanying unaudited condensed Consolidated Financial Statements. Due to seasonality and other factors, the results of operations for the interim period are not necessarily indicative of the results that will be realized for any other interim period or for the entire fiscal year. For further information, refer to the Consolidated Financial Statements and footnotes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016 (“2016 Form 10-K”). All business acquisitions completed during the periods presented have been accounted for using the purchase method of accounting, and their results of operations are included from the effective dates of the closings of the acquisitions. The allocations of purchase price to the assets acquired and liabilities assumed are assigned and recorded based on estimates of fair value and are subject to change within the purchase price allocation period (generally one year from the respective acquisition date). All intercompany balances and transactions have been eliminated in consolidation.
Segment Reporting Disclosure [Text Block]	Business Segment Information The Company has three reportable segments: the U.S., which includes the activities of the Company's corporate office, the U.K. and Brazil. The reportable segments are the business activities of the Company for which discrete financial information is available and for which operating results are regularly reviewed by its chief operating decision maker to allocate resources and assess performance. The Company's chief operating decision maker is its Chief Executive Officer.

Recently Adopted Accounting Pronouncements

In July 2015, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2015-11, Inventory (Topic 330): Simplifying the Measurement of Inventory. The amendments in the accounting standard replace the lower of cost or market test with a lower of cost and net realizable value test. The amendments in this ASU should be applied prospectively and are effective for interim and annual periods beginning after December 15, 2016. The Company adopted ASU 2015-11 during the first quarter of 2017. The adoption of this ASU did not materially impact its consolidated financial statements or results of operations.

In March 2016, the FASB issued ASU 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. The amendment addresses several aspects of the accounting for share-based payment award transactions, including: income tax consequences; classification of awards as either equity or liabilities; and classification on the statement of cash flows. The amendments in this ASU should be applied prospectively and are effective for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years. The Company adopted ASU 2016-09 during the first quarter of 2017. The adoption of this ASU did not materially impact its consolidated financial statements or results of operations.

Recently Issued Accounting Pronouncements

In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606) that amends the accounting guidance on revenue recognition. The amendments in this ASU are intended to provide a framework for addressing revenue issues, improve comparability of revenue recognition practices, and improve disclosure requirements. This ASU sets forth a five-step model for determining when and how revenue is recognized. Under the model, an entity will be required to recognize revenue to depict the transfer of goods or services to a customer at an amount reflecting the consideration it expects to receive in exchange for those goods or services. The amendments in this accounting standard update are effective for interim and annual reporting periods beginning after December 15, 2017. The standard can be adopted either retrospectively to each reporting period presented or as a cumulative effect adjustment as of the date of adoption. To assess the impact of the ASU, the Company established an internal implementation team to review its current accounting policies and practices, identify all material revenue streams, assess the impact of the ASU on its material revenue streams and identify potential differences with current policies and practices. The Company’s internal implementation team has substantially completed its initial review of the likely impacts that the application of the amendments in this ASU will have on its consolidated financial statements. The team has initially identified the Company’s material revenue streams to be the sale of new and used vehicles; arrangement of associated vehicle financing; the sale of service and insurance contracts; the performance of vehicle maintenance and repair services; and the sale of vehicle parts. The team has begun its review of a sample of associated contracts and other related documents, but currently, has not quantified an estimated impact of changes, if any, to its current revenue recognition policies and practices. The Company’s implementation team is in the preliminary stages of evaluating the additional disclosure requirements of the ASU, as well as the change, if any, to the Company’s underlying accounting and financial reporting systems and processes necessary to support the recognition and disclosure requirements. The Company expects to identify and implement the necessary changes, if any, during 2017. At this time, based on this review, the Company does not expect the adoption to materially impact its consolidated financial statements. The Company currently expects to adopt the amendments of this ASU during the first fiscal quarter of 2018, as a cumulative effect adjustment as of the date of adoption, but will not make a final decision on the adoption method until later in 2017.

In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842). The amendments in this ASU relate to the accounting for leasing transactions. This standard requires a lessee to record on the balance sheet the assets and liabilities for the rights and obligations created by leases with lease terms of more than 12 months. In addition, this standard requires both lessees and lessors to disclose certain key information about lease transactions. This standard will be effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. The Company is in the process of evaluating the impact that adoption will have on its consolidated balance sheet and statement of income. However, the Company expects that the adoption of the provisions of the ASU will have a significant impact on its consolidated balance sheet, as currently approximately half of its real estate is rented, not owned, via operating leases. Adoption of this ASU is required to be done using a modified retrospective approach.

In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326) Measurement of Credit Losses on Financial Instruments. The amendment 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 standard will be effective for fiscal years beginning after December 15, 2019, with early adoption permitted for periods after December 15, 2018. The Company is currently evaluating the impact that the adoption of the provisions of the ASU will have on its consolidated financial statements or results of operations.

In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments. The amendment addresses several specific cash flow issues with the objective of reducing the diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. The standard will be effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. The Company is currently evaluating the impact that the adoption of the provisions of the ASU will have on its consolidated financial statements.

In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash, a consensus of the FASB Emerging Issues Task Force ("EITF"). The amendments require that a statement of cash flows explain 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. The amendments in this ASU do not provide a definition of restricted cash or restricted cash equivalents. The standard will be effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. The Company is currently evaluating the impact that the adoption of the provisions of the ASU will have on its consolidated financial statements.

In January 2017, the FASB issued ASU 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business. The amendments in this update clarify the definition of a business in order to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The amendments in this ASU should be applied prospectively and are effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years, with early adoption permitted. The Company is currently evaluating the impact on its consolidated financial statements as it will depend on the facts and circumstances of any specific future transactions.

In January 2017, the FASB issued ASU 2017-03, Accounting Changes and Error Corrections (Topic 250) and Investments-Equity Method and Joint Ventures (Topic 323): Amendments to SEC Paragraphs Pursuant to Staff Announcements at the September 22, 2016 and November 17, 2016 EITF Meetings. The amendments in this update require the disclosure of the impact that a recently issued ASU will have on the financial statements of a registrant when such standards are to be adopted in a future period. The SEC staff view that a registrant should evaluate ASU's that have not yet been adopted to determine the appropriate financial statement disclosures about the potential material effects of those ASU's on the financial statements when adopted. The Company does not expect the amendments in this ASU to materially impact its consolidated financial statements.

In January 2017, the FASB issued ASU 2017-04, Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment. The amendment eliminates the requirement to calculate the implied fair value of goodwill to measure a goodwill impairment charge. Instead, entities will record an impairment charge based on the excess of a reporting unit's carrying amount over its fair value. The amendments in this update should be applied prospectively and are effective for interim and annual periods beginning after December 15, 2019. Earlier application is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. The Company is currently evaluating the impact that the adoption of the provisions of the ASU will have on its consolidated financial statements.