Basis of Presentation	9 Months Ended
Basis of Presentation	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying condensed consolidated financial statements of Systemax Inc., with its subsidiaries, (the "Company") are unaudited and have been prepared in accordance with accounting principles generally accepted in the United States of America for interim financial information and the rules and regulations of the Securities and Exchange Commission. Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America are not required in these interim financial statements and have been condensed or omitted. All significant intercompany accounts and transactions have been eliminated in consolidation. Systemax Inc., through its operating subsidiaries, is primarily a direct marketer of brand name and private label industrial and business equipment and supplies in North America going to market through a system of branded e-commerce websites and relationship marketers. Systemax operates and is internally managed in one reportable business segment. The Company sells a wide array of industrial and general hard goods and supplies and to a lesser extent products that would fall into the generally recognizable category of maintenance, repair and operations ("MRO"), markets the Company has served since 1949. Because of the large number of products and product categories the Company offers, providing information on the amount of revenue derived from transactions with external customers for each product or groupings of product is impractical. Included in discontinued operations is the Company’s former North American Technology Group ("NATG") business, which was sold in December 2015 and has been winding down its operations since then. Accordingly, these components and any related results of operations are reflected in discontinued operations. For the three and nine month periods ended September 30, 2020, net income from the NATG business totaled $0.5 million and $1.5 million, respectively, and for the three and nine month periods ended September 30, 2019, net loss from the NATG business totaled $1.0 million and $1.6 million, respectively. In the opinion of management, the accompanying condensed consolidated financial statements contain all normal and recurring adjustments necessary to present fairly the financial position of the Company as of September 30, 2020 and the results of operations for the three and nine month periods ended September 30, 2020 and 2019, statements of comprehensive income (loss) for the three and nine month periods ended September 30, 2020 and 2019, cash flows for the nine month periods ended September 30, 2020 and 2019 and changes in shareholders’ equity for the three and nine month periods ended September 30, 2020 and 2019. The December 31, 2019 Condensed Consolidated Balance Sheet has been derived from the audited consolidated financial statements included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2019. These condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements as of December 31, 2019 and for the year then ended included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2019. The results for the nine month period ended September 30, 2020 are not necessarily indicative of the results for the entire year. Systemax manages its business and reports using a 52-53 week fiscal year that ends at midnight on the Saturday closest to December 31. For clarity of presentation herein, fiscal years and quarters are referred to as if they ended on the traditional calendar month. The actual fiscal second quarter ended on September 26, 2020 and September 28, 2019. The third quarters of both 2020 and 2019 included 13 weeks and the first nine months of both 2020 and 2019 included 39 weeks. Related Party Transactions During 2020, the Company made inventory purchases of approximately $2.7 million from an entity owned by immediate family members of the Company's Executive Chairman. Amounts outstanding at September 30, 2020 totaled $0.6 million and are recorded in Accounts payable in the accompanying Condensed Consolidated Balance Sheet. During 2020, the Company recorded approximately $0.5 million in legal fee expense from a law firm which employs an immediate family member of one of the Company's Vice Chairman. There was a de minimis amount of outstanding payables to this entity at September 30, 2020. Also in 2020, the Company had sales of approximately $0.4 million to an entity that has on its parent company's board of trustees one of the Company's Board members. All of the foregoing transactions were carried out on an arm's length basis and with prior approval of the Company's Nominating and Corporate Governance Committee. Recent Accounting Pronouncements Public companies in the United States are subject to the accounting and reporting requirements of various authorities, including the Financial Accounting Standards Board (“FASB”) and the Securities and Exchange Commission (“SEC”). These authorities issue numerous pronouncements, most of which are not applicable to the Company’s current or reasonably foreseeable operating structure. In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. This ASU clarifies and simplifies accounting for income taxes by eliminating certain exceptions for intraperiod tax allocation principles and the methodology for calculating income tax rates in an interim period, among other updates. This ASU is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020, with early adoption permitted. The Company will adopt this ASU effective January 1, 2021. The Company believes the adoption of this pronouncement will not have a material impact on the Company's financial position or results of operations.