Business Overview and Significant Accounting Policies	9 Months Ended
Oct. 01, 2017
Accounting Policies [Abstract]
Business Overview and Significant Accounting Policies	Business Overview and Significant Accounting Policies Unless we state otherwise or the context otherwise requires, references to "Masonite," "we," "our," "us" and the "Company" in these notes to the condensed consolidated financial statements refer to Masonite International Corporation and its subsidiaries. Description of Business Masonite International Corporation is one of the largest manufacturers of doors in the world, with significant market share in both interior and exterior door products. Masonite operates 63 manufacturing locations in 8 countries and sells doors to customers throughout the world, including the United States, Canada and the United Kingdom. Basis of Presentation We prepare these unaudited condensed consolidated financial statements in accordance with accounting principles generally accepted in the United States of America ("GAAP") and applicable rules and regulations of the U.S. Securities and Exchange Commission ("SEC") regarding interim financial reporting. Accordingly, they do not include all of the information and notes required by GAAP for annual financial statements. In the opinion of management, all adjustments consisting of normal and recurring entries considered necessary for a fair presentation of the results for the interim periods presented have been included. All significant intercompany balances and transactions have been eliminated. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect reported amounts in the financial statements and accompanying notes. These estimates are based on information available as of the date of the unaudited condensed consolidated financial statements; therefore, actual results could differ from those estimates. Interim results are not necessarily indicative of the results for a full year. These unaudited condensed consolidated financial statements should be read in conjunction with the Company’s Annual Report on Form 10-K for the fiscal year ended January 1, 2017, as filed with the SEC. Our fiscal year is the 52- or 53-week period ending on the Sunday closest to December 31. In a 52-week year, each fiscal quarter consists of 13 weeks. For ease of disclosure, the 13- and 39-week periods are referred to as three- and nine-month periods, respectively. Changes in Accounting Standards and Policies There have been no changes in the significant accounting policies from those that were disclosed in the fiscal year 2016 audited consolidated financial statements, other than as noted below. Adoption of Recent Accounting Pronouncements In July 2015, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2015-11, "Simplifying the Measurement of Inventory," which amended ASC 330, "Inventory." This ASU requires the measurement of inventory at the lower of cost or net realizable value. Net realizable value is the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal and transportation. This ASU is effective for fiscal years beginning after December 15, 2016, and interim periods within those fiscal years; early adoption is permitted. The adoption of this standard did not have a material impact on the presentation of our financial statements. Other Recent Accounting Pronouncements not yet Adopted In March 2017, the FASB issued ASU 2017-07, “Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost,” which amends ASC 715, “Retirement Benefits”. This ASU requires disaggregation of the service cost component from the other components of net benefit cost. The other components of net benefit cost are 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 fiscal years beginning after December 15, 2017, and interim periods within those fiscal years; early adoption is permitted and retrospective application is required. We are in the process of evaluating this guidance to determine the impact it may have on our financial statements. In January 2017, the FASB issued ASU 2017-04, "Simplifying the Test for Goodwill Impairment", which amends ASC 350 "Intangibles - Goodwill and Other". This ASU simplifies the accounting for goodwill impairments and allows a goodwill impairment charge to be based upon the amount of a reporting unit's carrying value in excess of its fair value; thus, eliminating what is currently known as "Step 2" under the current guidance. This ASU is effective for annual periods beginning after December 15, 2019, and interim periods within those annual periods; early adoption is permitted and prospective application is required. We are in the process of evaluating this guidance to determine the impact it may have on our financial statements. In May 2014, the FASB issued ASU 2014-09, "Revenue from Contracts with Customers," which created ASC 606 and largely supersedes the existing guidance of ASC 605, including industry specific guidance. This standard outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers. The core principle of the revenue model is that an entity recognizes revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In August 2015, the FASB issued ASU 2015-14, "Revenue from Contracts with Customers - Deferral of the Effective Date," and the guidance will now be effective for annual and interim periods beginning on or after December 15, 2017. While we are still finalizing the evaluation of our contracts with our customers and the effect of adoption on our consolidated financial statements, we do not currently expect the adoption of the new standard to have a material impact on consolidated net income (loss) attributable to Masonite, cash flows or our consolidated balance sheets. We previously disclosed that we planned to adopt this standard using the full retrospective method. As we have progressed in our evaluation of our contracts with customers, we have changed our approach and we now intend to adopt this standard using the modified retrospective method due to the lack of material impact of the adoption. We plan to apply the standard to only those contracts which were not completed as of the transition date and adoption will be effective as of January 1, 2018.

Business Overview and Significant Accounting Policies

Unless we state otherwise or the context otherwise requires, references to "Masonite," "we," "our," "us" and the "Company" in these notes to the condensed consolidated financial statements refer to Masonite International Corporation and its subsidiaries.

Description of Business

Masonite International Corporation is one of the largest manufacturers of doors in the world, with significant market share in both interior and exterior door products. Masonite operates 63 manufacturing locations in 8 countries and sells doors to customers throughout the world, including the United States, Canada and the United Kingdom.

Basis of Presentation

We prepare these unaudited condensed consolidated financial statements in accordance with accounting principles generally accepted in the United States of America ("GAAP") and applicable rules and regulations of the U.S. Securities and Exchange Commission ("SEC") regarding interim financial reporting. Accordingly, they do not include all of the information and notes required by GAAP for annual financial statements. In the opinion of management, all adjustments consisting of normal and recurring entries considered necessary for a fair presentation of the results for the interim periods presented have been included. All significant intercompany balances and transactions have been eliminated. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect reported amounts in the financial statements and accompanying notes. These estimates are based on information available as of the date of the unaudited condensed consolidated financial statements; therefore, actual results could differ from those estimates. Interim results are not necessarily indicative of the results for a full year.

These unaudited condensed consolidated financial statements should be read in conjunction with the Company’s Annual Report on Form 10-K for the fiscal year ended January 1, 2017, as filed with the SEC. Our fiscal year is the 52- or 53-week period ending on the Sunday closest to December 31. In a 52-week year, each fiscal quarter consists of 13 weeks. For ease of disclosure, the 13- and 39-week periods are referred to as three- and nine-month periods, respectively.

Changes in Accounting Standards and Policies

There have been no changes in the significant accounting policies from those that were disclosed in the fiscal year 2016 audited consolidated financial statements, other than as noted below.

Adoption of Recent Accounting Pronouncements

In July 2015, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2015-11, "Simplifying the Measurement of Inventory," which amended ASC 330, "Inventory." This ASU requires the measurement of inventory at the lower of cost or net realizable value. Net realizable value is the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal and transportation. This ASU is effective for fiscal years beginning after December 15, 2016, and interim periods within those fiscal years; early adoption is permitted. The adoption of this standard did not have a material impact on the presentation of our financial statements.

Other Recent Accounting Pronouncements not yet Adopted

In March 2017, the FASB issued ASU 2017-07, “Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost,” which amends ASC 715, “Retirement Benefits”. This ASU requires disaggregation of the service cost component from the other components of net benefit cost. The other components of net benefit cost are 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 fiscal years beginning after December 15, 2017, and interim periods within those fiscal years; early adoption is permitted and retrospective application is required. We are in the process of evaluating this guidance to determine the impact it may have on our financial statements.

In January 2017, the FASB issued ASU 2017-04, "Simplifying the Test for Goodwill Impairment", which amends ASC 350 "Intangibles - Goodwill and Other". This ASU simplifies the accounting for goodwill impairments and allows a goodwill impairment charge to be based upon the amount of a reporting unit's carrying value in excess of its fair value; thus, eliminating what is currently known as "Step 2" under the current guidance. This ASU is effective for annual periods beginning after December 15, 2019, and interim periods within those annual periods; early adoption is permitted and prospective application is required. We are in the process of evaluating this guidance to determine the impact it may have on our financial statements.

In May 2014, the FASB issued ASU 2014-09, "Revenue from Contracts with Customers," which created ASC 606 and largely supersedes the existing guidance of ASC 605, including industry specific guidance. This standard outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers. The core principle of the revenue model is that an entity recognizes revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In August 2015, the FASB issued ASU 2015-14, "Revenue from Contracts with Customers - Deferral of the Effective Date," and the guidance will now be effective for annual and interim periods beginning on or after December 15, 2017. While we are still finalizing the evaluation of our contracts with our customers and the effect of adoption on our consolidated financial statements, we do not currently expect the adoption of the new standard to have a material impact on consolidated net income (loss) attributable to Masonite, cash flows or our consolidated balance sheets. We previously disclosed that we planned to adopt this standard using the full retrospective method. As we have progressed in our evaluation of our contracts with customers, we have changed our approach and we now intend to adopt this standard using the modified retrospective method due to the lack of material impact of the adoption. We plan to apply the standard to only those contracts which were not completed as of the transition date and adoption will be effective as of January 1, 2018.