Summary of Significant Accounting Policies	9 Months Ended
Summary of Significant Accounting Policies	Sep. 29, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation The accompanying unaudited Condensed Consolidated Financial Statements include the accounts of BlueLinx Holdings Inc. and its wholly owned subsidiaries (the “Company”). These financial statements have been prepared in accordance with the instructions to Form 10-Q and do not include all of the information and footnotes required by accounting principles generally accepted (“GAAP”) in the United States (“U.S.”) for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation have been included. These statements should be read in conjunction with the Consolidated Financial Statements and notes thereto included in the Company’s Annual Report on Form 10-K (the “Annual Report on Form 10-K”) for the year ended December 30, 2017, as filed with the Securities and Exchange Commission on March 1, 2018. Our financial condition as of, and our operating results for, the three- and nine-month periods ended September 29, 2018 are not necessarily indicative of the financial condition and results that may be expected for the full year ending December 29, 2018 or any other interim period. Certain prior period amounts have been reclassified to conform to the current period's presentation. These reclassifications did not materially impact the Company's operating income (loss) or consolidated net income (loss). Inventory Valuation Inventories are valued at the lower of cost or net realizable value. The Company’s inventory is comprised of finished goods. Cost is determined based on the moving average cost method of inventory valuation. We evaluated our inventory value at the end of each quarter to ensure that inventory, when viewed by category, is carried at lower of cost and net realizable value. In valuing inventory, the Company is required to make assumptions regarding the level of reserves required to value potentially obsolete or over-valued items at the lower of cost or net realizable value. As of September 29, 2018, and December 30, 2017, the Company decreased the value of inventory on hand by $5.2 million and $0, respectively, as a result of a decline in commodity pricing. Recently Adopted Accounting Standards Revenue from Contracts with Customers. In 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09, “Revenue from Contracts with Customers (Topic 606)” (“ASC 606”) that superseded existing revenue recognition guidance. Under this ASU and subsequently issued amendments, revenue is recognized at the time a good or service is transferred to a customer for the amount of consideration received. The standard was effective for the first interim period within annual periods beginning after December 15, 2017, with early adoption permitted for annual periods beginning after December 15, 2016. Entities were permitted to adopt the standard using a “full retrospective” approach (retrospectively to each prior reporting period presented) or a “modified retrospective” approach (reporting the cumulative effect as of the date of adoption). On December 31, 2017, the first day of our fiscal 2018 year, we adopted ASC 606 using the modified retrospective method applied to those contracts which were not completed as of that date. Results for reporting periods beginning after the first day of fiscal 2018 are presented under ASC 606, while prior period amounts are not adjusted and continue to be reported in accordance with our historic accounting under the previous accounting standard, ASC 605. There was no adjustment due to the cumulative impact of adopting ASC 606 (See Note 4). Accounting Standards Effective in Future Years Leases. In 2016, the FASB issued ASU No. 2016-02, “Leases (Topic 842).” This update will require leases with durations greater than twelve months to be recognized on the balance sheet and is effective for interim and annual reporting periods beginning after December 15, 2018. We will adopt this standard, and all related amendments thereto, effective December 30, 2018, the first day of our fiscal 2019 year. We have not completed our assessment, but the adoption of this standard will have a significant impact on our Condensed Consolidated Balance Sheets. However, we do not expect the adoption to have a significant impact on the recognition, measurement or presentation of lease expense within the Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) or the Condensed Consolidated Statements of Cash Flows. Information about our undiscounted future lease payments and the timing of those payments is presented in Note 13, “Lease Commitments,” in our Annual Report on Form 10-K. Goodwill. In January 2017, the FASB issued ASU No. 2017-04, “Intangibles—Goodwill and Other (Topic 350).” This standard is intended to simplify the test for goodwill impairments by removing Step 2 of the goodwill impairment test, which requires a hypothetical purchase price allocation. Under the new ASU, a goodwill impairment will now be the amount by which a reporting unit's carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. The accounting standard will be effective for reporting periods beginning after December 15, 2019, and early adoption is permitted. We have not completed our assessment of the standard but we do not expect the adoption to have a material impact on the Company's consolidated financial position, results of operations and cash flows. Comprehensive Income. In February 2018, the FASB issued ASU No. 2018-02, “Income Statement—Reporting Comprehensive Income (Topic 220).” This standard provides an option to reclassify stranded tax effects within accumulated other comprehensive income (loss) (“AOCI”) to retained earnings due to the U.S. federal corporate income tax rate change in the Tax Cuts and Jobs Act of 2017. This standard is effective for interim and annual reporting periods beginning after December 15, 2018, and early adoption is permitted. We have not completed our assessment, but the adoption of the standard may impact tax amounts stranded in AOCI related to our pension plans. We will adopt this standard effective December 30, 2018, the first day of our fiscal 2019 year. Fair Value Measurement. In August 2018, the FASB issued ASU No. 2018-13, “Fair Value (“FV”) Measurement (Topic 820)”. In addition to making certain modifications, the standard removes the requirements to disclose: (i) the amount of and reasons for transfers between Level 1 and Level 2 of the FV hierarchy; (ii) the policy for timing transfers between levels; and (iii) the valuation process for Level 3 FV measurements. The standard will require public entities to disclose: (i) the changes in unrealized gains and losses for the period included in other comprehensive income for recurring Level 3 FV measurements held at the end of the reporting period; and (ii) the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. For certain unobservable inputs, an entity may disclose other quantitative information in lieu of the weighted average if the entity determines that other quantitative information would be a more reasonable and rational method to reflect the distribution of unobservable inputs used to develop Level 3 FV measurements. The additional disclosure requirements should be applied prospectively for the most recent interim or annual period presented in the fiscal year of adoption. All other amendments should be applied retrospectively to all periods presented. The amendments in this standard are effective for fiscal years ending after December 15, 2019. Early adoption is permitted, and an entity may early adopt the removed or modified disclosures and delay the adoption of new disclosures until the effective date. We have not completed our assessment of the standard but we do not expect the adoption to have a material impact on the Company's consolidated financial position, results of operations and cash flows. Defined Benefit Pension Plan. In August 2018, the FASB issued ASU No. 2018-14, “Compensation-Retirement-Benefits-Defined Benefit Plans-General (Subtopic 715-20)”. The amendments in this update modify the disclosure requirements for employers that sponsor defined benefit pension or other postretirement plans by removing six previously required disclosures and adding two. The amendments also clarify certain disclosure requirements. The amendments in this standard are effective for fiscal years ending after December 15, 2020. Early adoption is permitted. We have not completed our assessment of the standard but we do not expect the adoption to have a material impact on the Company's consolidated financial position, results of operations and cash flows.