Summary of Significant Accounting Policies	12 Months Ended
Dec. 30, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation BlueLinx is a wholesale distributor of building and industrial products in the U.S. Our Consolidated Financial Statements include the accounts of BlueLinx Holdings Inc. and its wholly owned subsidiaries. These financial statements have been prepared in accordance with U.S. GAAP. All significant intercompany accounts and transactions have been eliminated. Fiscal years 2017, 2016, and 2015 were each comprised of 52 weeks. Our fiscal year ends on the Saturday closest to December 31 of that fiscal year, and may comprise 53 weeks in certain years. Use of Estimates We are required to make estimates and assumptions when preparing our Consolidated Financial Statements in accordance with U.S. GAAP. These estimates and assumptions affect the amounts reported in our Consolidated Financial Statements and the accompanying notes. Actual results could differ materially from those estimates. Recent Accounting Standards - Recently Issued Revenue from Contracts with Customers. In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (“ASU”) 2014-09, as later amended, which resulted in a new accounting standard “Revenue from Contracts with Customers (Topic 606),” which supersedes the revenue recognition requirements in Accounting Standards Codification (“ASC”) 605, Revenue Recognition. The new revenue recognition standard requires entities to recognize revenue in a way that depicts the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. ASU 2014-09 will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective. The new standard is effective on January 1, 2018. We have elected to adopt the revenue recognition standard in the first quarter of 2018 with a cumulative adjustment to retained earnings. We have completed our assessment of the new revenue recognition guidance. We do not anticipate the adoption of this standard to have a material impact on our financial statements, aside from adding expanded required disclosures. Leases. In February 2016, the FASB issued ASU 2016-02, “Leases.” The new standard establishes a right-of-use model that requires a lessee to record a right-of-use asset and a lease liability on the balance sheet for all leases with terms longer than twelve months. Leases will be classified as either “finance” or “operating,” with classification affecting the pattern of expense recognition in the income statement. The new standard is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. A modified retrospective transition approach is required for lessees for capital and operating leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements, with certain practical expedients available. Early adoption is permitted. We plan to adopt this accounting standard in the first quarter of 2019. Adoption of this standard may have a significant impact on our Consolidated Balance Sheets, especially pertaining to the capitalization of operating leases and transition provisions relating to sale-leaseback transactions. Although we have not completed our assessment, we do not expect the adoption to change the recognition, measurement, or presentation of lease expenses within the Consolidated Statements of Operations and Cash Flows. For information about our current undiscounted future lease payments and the timing of those payments, see Note 13, “Lease Commitments.” Recent Accounting Standards - Recently Adopted Inventories. In July 2015, the FASB issued ASU 2015-11, “Inventory.” The ASU requires entities that measure inventory using methods including the average cost method to measure inventory at the lower of cost and net realizable value. We adopted the provisions of this accounting standard in the first quarter of 2017, and there were no adjustments resulting from our adoption of the provisions of this accounting standard. Pension. In March, 2017, the FASB issued ASU 2017-07, “Compensation—Retirement Benefits (Topic 715).” This standard requires an entity to report the service cost component in the same line item as other compensation costs. The other components of net (credit) cost will be required to be presented in the income statement separately from the service cost component and outside a subtotal of income from operations. This standard is effective for interim and annual reporting periods beginning after December 15, 2017, and early adoption is permitted at the beginning of an annual period. We chose to adopt this presentation in the first quarter of fiscal 2017, and our financial statements have been retrospectively adjusted for the prior comparative period. The components of the net (credit) cost are shown in Note 9, “Employee Benefits,” and the components as shown for the prior comparative period were used as the estimation basis for applying the retrospective presentation requirements, as allowed by the practical expedient of this ASU. Revenue Recognition We recognize revenue when the following criteria are met: persuasive evidence of an agreement exists, delivery has occurred or services have been rendered, our price to the buyer is fixed or determinable, and collectability is reasonably assured. Delivery is not considered to have occurred until the customer takes title and assumes the risks and rewards of ownership. The timing of revenue recognition largely is dependent on shipping terms. Revenue is recorded at the time of shipment for terms designated free on board (“FOB”) shipping point. For sales transactions designated FOB destination, revenue is recorded when the product is delivered to the customer’s delivery site. In addition, we provide inventory to certain customers through pre-arranged agreements on a consignment basis. Customer consigned inventory is maintained and stored by certain customers; however, ownership and risk of loss remains with us. When the consigned inventory is sold by the customer, we recognize revenue on a gross basis. All revenues recognized are net of trade allowances, cash discounts, and sales returns. Cash discounts and sales returns are estimated using historical experience. Trade allowances are based on the estimated obligations and historical experience. Adjustments to earnings resulting from revisions to estimates on discounts and returns have been insignificant for each of the reported periods. Accounts Receivable Accounts receivable are stated at net realizable value, do not bear interest, and consist of amounts owed for orders shipped to customers. Management establishes an overall credit policy for sales to customers. The allowance for doubtful accounts is determined based on a number of factors including specific customer account reviews, historical loss experience, current economic trends, and the creditworthiness of significant customers based on ongoing credit evaluations. Inventory Valuation The cost of all inventories is determined by the moving average cost method. We have included all material charges directly or indirectly incurred in bringing inventory to its existing condition and location. We evaluate our inventory value at the end of each quarter to ensure that inventory, when viewed by category, is carried at the lower of cost and net realizable value, which also considers items that may be damaged, excess, and obsolete inventory. Consideration Received from Vendors and Paid to Customers Each year, we enter into agreements with many of our vendors providing for inventory purchase rebates, generally based on achievement of specified volume purchasing levels. We also receive rebates related to price protection and various marketing allowances that are common industry practice. We accrue for the receipt of vendor rebates based on purchases, and also reduce inventory to reflect the net acquisition cost (purchase price less expected purchase rebates). In addition, we enter into agreements with many of our customers to offer customer rebates, generally based on achievement of specified sales levels and various marketing allowances that are common industry practice. We accrue for the payment of customer rebates based on sales to the customer, and also reduce sales to reflect the net sales (sales price less expected customer rebates). Adjustments to earnings resulting from revisions to rebate estimates have been immaterial. Shipping and Handling Amounts billed to customers in sales transactions related to shipping and handling are classified as revenue. Shipping and handling costs included in “Selling, general, and administrative” expenses were $83.1 million, $89.0 million, and $88.4 million for fiscal 2017, fiscal 2016, and fiscal 2015, respectively. Property and Equipment Property and equipment are recorded at cost. Lease obligations for which we assume or retain substantially all the property rights and risks of ownership are capitalized. Amortization of assets recorded under capital leases is included in “Depreciation and amortization” expense. Replacements of major units of property are capitalized and the replaced properties are retired. Replacements of minor components of property and repair and maintenance costs are charged to expense as incurred. Depreciation is computed using the straight-line method over the estimated useful lives of the related assets. Upon retirement or disposition of assets, cost and accumulated depreciation are removed from the related accounts and any gain or loss is included in income. Income Taxes We account for deferred income taxes using the liability method. Accordingly, we recognize deferred tax assets and liabilities based on the tax effects of temporary differences between the financial statement and tax bases of assets and liabilities, as measured by current enacted tax rates. All deferred tax assets and liabilities are classified as noncurrent in our consolidated balance sheet in accordance with ASU 2015-17. We adopted these provisions prospectively on January 2, 2016, and prior periods were not retrospectively adjusted. A valuation allowance is recorded to reduce deferred tax assets when necessary. For additional information about our income taxes, see Note 5, “Income Taxes.” Insurance and Self-Insurance For fiscal 2015, the Company was self-insured, up to certain limits, for non-union and certain unionized employee health benefits. For fiscal 2016 and 2017, the Company purchased an insurance policy for its non-union and certain unionized employee health benefits, and was fully insured for this obligation. Health benefits for some unionized employees for fiscal 2017, 2016 and 2015 were paid directly to a union trust, depending upon the union-negotiated benefit arrangement. For fiscal 2017, 2016 and 2015, the Company was self-insured, up to certain limits, for most workers’ compensation losses, general liability, and automotive liability losses, all subject to varying “per occurrence” retentions or deductible limits. The Company provides for estimated costs to settle both known claims and claims incurred but not yet reported. Liabilities associated with these claims are estimated, in part, by considering the frequency and severity of historical claims, both specific to us, as well as industry-wide loss experience and other actuarial assumptions. We determine our insurance obligations with the assistance of actuarial firms. Since there are many estimates and assumptions involved in recording insurance liabilities and in the case of workers’ compensation, a significant period of time elapses before the ultimate resolution of claims, differences between actual future events and prior estimates and assumptions could result in adjustments to these liabilities.

BlueLinx is a wholesale distributor of building and industrial products in the U.S. Our Consolidated Financial Statements include the accounts of BlueLinx Holdings Inc. and its wholly owned subsidiaries. These financial statements have been prepared in accordance with U.S. GAAP. All significant intercompany accounts and transactions have been eliminated.

We are required to make estimates and assumptions when preparing our Consolidated Financial Statements in accordance with U.S. GAAP. These estimates and assumptions affect the amounts reported in our Consolidated Financial Statements and the accompanying notes. Actual results could differ materially from those estimates.

Revenue from Contracts with Customers. In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (“ASU”) 2014-09, as later amended, which resulted in a new accounting standard “Revenue from Contracts with Customers (Topic 606),” which supersedes the revenue recognition requirements in Accounting Standards Codification (“ASC”) 605, Revenue Recognition. The new revenue recognition standard requires entities to recognize revenue in a way that depicts the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. ASU 2014-09 will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective. The new standard is effective on January 1, 2018. We have elected to adopt the revenue recognition standard in the first quarter of 2018 with a cumulative adjustment to retained earnings. We have completed our assessment of the new revenue recognition guidance. We do not anticipate the adoption of this standard to have a material impact on our financial statements, aside from adding expanded required disclosures.

Leases. In February 2016, the FASB issued ASU 2016-02, “Leases.” The new standard establishes a right-of-use model that requires a lessee to record a right-of-use asset and a lease liability on the balance sheet for all leases with terms longer than twelve months. Leases will be classified as either “finance” or “operating,” with classification affecting the pattern of expense recognition in the income statement. The new standard is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. A modified retrospective transition approach is required for lessees for capital and operating leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements, with certain practical expedients available. Early adoption is permitted. We plan to adopt this accounting standard in the first quarter of 2019.

Adoption of this standard may have a significant impact on our Consolidated Balance Sheets, especially pertaining to the capitalization of operating leases and transition provisions relating to sale-leaseback transactions. Although we have not completed our assessment, we do not expect the adoption to change the recognition, measurement, or presentation of lease expenses within the Consolidated Statements of Operations and Cash Flows. For information about our current undiscounted future lease payments and the timing of those payments, see Note 13, “Lease Commitments.”

Inventories. In July 2015, the FASB issued ASU 2015-11, “Inventory.” The ASU requires entities that measure inventory using methods including the average cost method to measure inventory at the lower of cost and net realizable value. We adopted the provisions of this accounting standard in the first quarter of 2017, and there were no adjustments resulting from our adoption of the provisions of this accounting standard.

Pension. In March, 2017, the FASB issued ASU 2017-07, “Compensation—Retirement Benefits (Topic 715).” This standard requires an entity to report the service cost component in the same line item as other compensation costs. The other components of net (credit) cost will be required to be presented in the income statement separately from the service cost component and outside a subtotal of income from operations. This standard is effective for interim and annual reporting periods beginning after December 15, 2017, and early adoption is permitted at the beginning of an annual period. We chose to adopt this presentation in the first quarter of fiscal 2017, and our financial statements have been retrospectively adjusted for the prior comparative period. The components of the net (credit) cost are shown in Note 9, “Employee Benefits,” and the components as shown for the prior comparative period were used as the estimation basis for applying the retrospective presentation requirements, as allowed by the practical expedient of this ASU.

We recognize revenue when the following criteria are met: persuasive evidence of an agreement exists, delivery has occurred or services have been rendered, our price to the buyer is fixed or determinable, and collectability is reasonably assured. Delivery is not considered to have occurred until the customer takes title and assumes the risks and rewards of ownership. The timing of revenue recognition largely is dependent on shipping terms. Revenue is recorded at the time of shipment for terms designated free on board (“FOB”) shipping point. For sales transactions designated FOB destination, revenue is recorded when the product is delivered to the customer’s delivery site.

In addition, we provide inventory to certain customers through pre-arranged agreements on a consignment basis. Customer consigned inventory is maintained and stored by certain customers; however, ownership and risk of loss remains with us. When the consigned inventory is sold by the customer, we recognize revenue on a gross basis.

All revenues recognized are net of trade allowances, cash discounts, and sales returns. Cash discounts and sales returns are estimated using historical experience. Trade allowances are based on the estimated obligations and historical experience. Adjustments to earnings resulting from revisions to estimates on discounts and returns have been insignificant for each of the reported periods.

Accounts receivable are stated at net realizable value, do not bear interest, and consist of amounts owed for orders shipped to customers. Management establishes an overall credit policy for sales to customers. The allowance for doubtful accounts is determined based on a number of factors including specific customer account reviews, historical loss experience, current economic trends, and the creditworthiness of significant customers based on ongoing credit evaluations.

The cost of all inventories is determined by the moving average cost method. We have included all material charges directly or indirectly incurred in bringing inventory to its existing condition and location. We evaluate our inventory value at the end of each quarter to ensure that inventory, when viewed by category, is carried at the lower of cost and net realizable value, which also considers items that may be damaged, excess, and obsolete inventory.

Each year, we enter into agreements with many of our vendors providing for inventory purchase rebates, generally based on achievement of specified volume purchasing levels. We also receive rebates related to price protection and various marketing allowances that are common industry practice. We accrue for the receipt of vendor rebates based on purchases, and also reduce inventory to reflect the net acquisition cost (purchase price less expected purchase rebates).

In addition, we enter into agreements with many of our customers to offer customer rebates, generally based on achievement of specified sales levels and various marketing allowances that are common industry practice. We accrue for the payment of customer rebates based on sales to the customer, and also reduce sales to reflect the net sales (sales price less expected customer rebates). Adjustments to earnings resulting from revisions to rebate estimates have been immaterial.

Amounts billed to customers in sales transactions related to shipping and handling are classified as revenue. Shipping and handling costs included in “Selling, general, and administrative” expenses were $83.1 million, $89.0 million, and $88.4 million for fiscal 2017, fiscal 2016, and fiscal 2015, respectively.

Property and equipment are recorded at cost. Lease obligations for which we assume or retain substantially all the property rights and risks of ownership are capitalized. Amortization of assets recorded under capital leases is included in “Depreciation and amortization” expense. Replacements of major units of property are capitalized and the replaced properties are retired. Replacements of minor components of property and repair and maintenance costs are charged to expense as incurred.

Depreciation is computed using the straight-line method over the estimated useful lives of the related assets. Upon retirement or disposition of assets, cost and accumulated depreciation are removed from the related accounts and any gain or loss is included in income.

We account for deferred income taxes using the liability method. Accordingly, we recognize deferred tax assets and liabilities based on the tax effects of temporary differences between the financial statement and tax bases of assets and liabilities, as measured by current enacted tax rates. All deferred tax assets and liabilities are classified as noncurrent in our consolidated balance sheet in accordance with ASU 2015-17. We adopted these provisions prospectively on January 2, 2016,

For fiscal 2015, the Company was self-insured, up to certain limits, for non-union and certain unionized employee health benefits. For fiscal 2016 and 2017, the Company purchased an insurance policy for its non-union and certain unionized employee health benefits, and was fully insured for this obligation. Health benefits for some unionized employees for fiscal 2017, 2016 and 2015 were paid directly to a union trust, depending upon the union-negotiated benefit arrangement.