Basis of Presentation (Policies)	6 Months Ended
Basis of Presentation (Policies)	Jun. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Principles of Consolidation	Principles of Consolidation The condensed consolidated financial statements include the accounts of Simpson Manufacturing Co., Inc. and its subsidiaries (collectively, the “Company”). There were no investments in affiliates that would render such affiliates to be considered variable interest entities. All significant intercompany transactions have been eliminated.
Interim Period Reporting	Interim Period Reporting The accompanying unaudited interim condensed consolidated financial statements have been prepared pursuant to the rules and regulations for reporting on Form 10-Q. Accordingly, certain information and footnotes required by accounting principles generally accepted in the United States of America (“GAAP”) have been condensed or omitted. These interim statements should be read in conjunction with the audited consolidated financial statements and the notes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2016. The unaudited quarterly condensed consolidated financial statements have been prepared on the same basis as the audited annual consolidated financial statements and, in the opinion of management, contain all adjustments (consisting of only normal recurring adjustments) necessary to state fairly the financial information set forth therein, in accordance with GAAP. The year-end condensed consolidated balance sheet data provided herein were derived from audited financial statements, but do not include all disclosures required by GAAP. The Company’s quarterly results fluctuate. As a result, the Company believes the results of operations for this interim period presented are not indicative of the results to be expected for any future periods.
Revenue Recognition	Revenue Recognition The Company recognizes revenue when the earnings process is complete, net of applicable provision for discounts, returns and incentives, whether actual or estimated, based on the Company’s experience. This generally occurs when products are shipped to the customer in accordance with the sales agreement or purchase order, ownership and risk of loss pass to the customer, collectability is reasonably assured and pricing is fixed or determinable. The Company’s general shipping terms are F.O.B. shipping point, and title is transferred and revenue is recognized when the products are shipped to customers. When the Company sells F.O.B. destination point, title is transferred and the Company recognizes revenue on delivery or customer acceptance, depending on terms of the sales agreement. Service sales, representing after-market repair and maintenance, engineering activities and software license sales and services, though less than 1.0% net sales and not material to the condensed consolidated financial statements, are recognized as the services are completed or the software products and services are delivered. If actual costs of sales returns, incentives and discounts were to significantly exceed the recorded estimated allowance, the Company’s sales would be adversely affected.
Net Earnings Per Common Share	Net Earnings Per Common Share Basic earnings per common share are computed based on the weighted-average number of common shares outstanding. Potentially dilutive securities, using the treasury stock method, are included in the diluted per-share calculations for all periods when the effect of their inclusion is dilutive.
Accounting for Stock-Based Compensation	Accounting for Stock-Based Compensation The Company currently maintains an equity incentive plan, the Simpson Manufacturing Co., Inc. Amended and Restated 2011 Incentive Plan (the “2011 Plan”), which was originally adopted on April 26, 2011 and was subsequently amended and restated on April 21, 2015. The 2011 Plan amended and restated in their entirety, and incorporated and superseded, both the Simpson Manufacturing Co., Inc. 1994 Stock Option Plan (the “1994 Plan”), which was principally for the Company’s employees, and the Simpson Manufacturing Co., Inc. 1995 Independent Director Stock Option Plan (the “1995 Plan”), which was for its independent directors. Awards previously granted under the 1994 Plan or the 1995 Plan were not affected by the adoption of the 2011 Plan and continued to be governed by the 1994 Plan or the 1995 Plan, respectively. Under the 1994 Plan and the 1995 Plan, the Company could grant incentive stock options and non-qualified stock options, although the Company granted only non-qualified stock options thereunder. The Company generally granted stock options under each of the 1994 Plan and the 1995 Plan once every year. Stock options vest and expire according to terms established at the grant date. Stock options granted under the 1994 Plan typically vested evenly over the requisite service period of four years and have a term of seven years. Stock options granted under the 1995 Plan typically fully vest on the date of grant. Shares of common stock issued on exercise of stock options under the 1994 Plan and the 1995 Plan are registered under the Securities Act of 1933, as amended (the "Securities Act"). Under the 2011 Plan, the Company may grant incentive stock options, non-qualified stock options, restricted stock and restricted stock units ("RSUs"), although the Company currently intends to award primarily performance-based and/or time-based RSUs and to a lesser extent, if at all, non-qualified stock options (see "Note 9 Stock-Based Incentive Plans") to its employees. The Company currently intends to grant RSUs that vest on the date of grant to its independent directors. The Company does not currently intend to award incentive stock options or restricted stock. Under the 2011 Plan, no more than 16.3 million shares of the Company’s common stock in aggregate may be issued under the 2011 Plan, including shares already issued pursuant to prior awards and shares reserved for issuance on exercise of options previously granted under the 1994 Plan and the 1995 Plan. Shares of common stock to be issued pursuant to the 2011 Plan are registered under the Securities Act. Subject to certain adjustments, the following limits shall apply with respect to any awards under the 2011 Plan that are intended to qualify for the performance-based exception from the tax deductibility limitations of section 162(m) of the U.S. Internal Revenue Code of 1986, as amended from time to time: (i) the maximum aggregate number of shares of the Company’s common stock that may be subject to stock options granted in any calendar year to any one participant shall be 150,000 shares; and (ii) the maximum aggregate number of shares of the Company’s common stock issuable or deliverable under RSUs granted in any calendar year to any one participant shall be 100,000 shares.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The “Fair Value Measurements and Disclosures” topic of the Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) establishes a valuation hierarchy for disclosure of the inputs used to measure fair value. This hierarchy prioritizes the inputs into three broad levels as follows: Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities; Level 2 inputs are quoted prices for similar assets and liabilities in active markets or inputs that are observable for the asset or liability, either directly or indirectly through market corroboration, for substantially the full term of the financial instrument; and Level 3 inputs are unobservable inputs based on the Company’s assumptions used to measure assets and liabilities at fair value. A financial asset’s or liability’s classification within the hierarchy is determined based on the lowest level input that is significant to the fair value measurement.
Income Taxes	Income Taxes The Company uses an estimated annual effective tax rate to measure the tax benefit or tax expense recognized in each interim period.
Acquisitions	Acquisitions Under the business combinations topic of the FASB ASC 805, the Company accounts for acquisitions as business combinations and ascribes acquisition-date fair values to the acquired assets and assumed liabilities. Provisional fair value measurements are made at the time of the acquisitions. Adjustments to those measurements may be made in subsequent periods, up to one year from the acquisition date, as information necessary to complete the analysis is obtained. Fair value of intangible assets are generally based on Level 3 inputs.
Recently Issued Accounting Standards	Recently Adopted Accounting Standards In March 2016, the FASB issued Accounting Standards Update No. 2016-09, Compensation - Stock Compensation (Topic 718), Improvements to Employee Share-Based Payment Accounting ("ASU 2016-09"), which amends existing guidance related to accounting for employee share-based payments affecting the income tax consequences of awards, classification of awards as equity or liabilities, and classification on the statement of cash flows. ASU 2016-09 is effective for fiscal years, and interim periods within those fiscal years beginning after December 15, 2016, with early adoption permitted. On January 1, 2017, the Company adopted ASU 2016-09. This new guidance requires all excess tax benefits and tax deficiencies be recognized as income tax expense or benefit in the income statement and classified as an operating activity in the statement of cash flows. The Company prospectively adopted this guidance with the tax impact of a $1.1 million tax benefit recognized in the consolidated income statements and classified it as an operating activity in the consolidated statement of cash flows. The guidance also requires a policy election either to estimate the number of awards that are expected to vest or to account for forfeitures whenever they occur. The Company did not change its policy for calculating accrual compensation costs by estimating the number of awards that are expected to vest. Therefore, when the Company adopted this guidance, there was no recognized cumulative effect adjustment to retained earnings. In addition, this guidance requires cash paid by an employer, when directly withholding shares for tax withholding purposes, to be classified in the statement of cash flows as a financing activity, which differs from the Company's previous method of classification of such cash payments as an operating activity. Accordingly, the Company applied this provision retrospectively and for the six months ended June 30, 2017 and 2016 and reclassified $5.2 million and $4.0 million, respectively, from operating activities to financing activities in the condensed consolidated statements of cash flows. In March 2016, the FASB issued Accounting Standards Update No. 2016-07, Simplifying the Transition to the Equity Method of Accounting ("ASU 2016-07"), which eliminates the requirement to apply the equity method of accounting retrospectively when a reporting entity obtains significant influence over a previously held investment. The amendments in ASU 2016-07 are effective for public companies for fiscal years beginning after December 15, 2016, including interim periods therein, with early adoption permitted. The new standard should be applied prospectively for investments that qualify for the equity method of accounting after the effective date. On January 1, 2017, the Company prospectively adopted ASU 2016-07. Adoption of ASU 2016-07 has had no material effect on the Company's consolidated financial statements and footnote disclosures. In January 2017, the FASB issued Accounting Standards Updated No. 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business ("ASU 2017-01"), which changes the definition of a business to assist entities with evaluating when a set of transferred assets and activities is a business. The new guidance clarifies that a business must also include at least one substantive process and narrows the definition of outputs by more closely aligning it with how outputs are described in ASC 606, Revenue from Contracts with Customers. ASU 2017-01 is effective for fiscal years, and interim periods within those fiscal years beginning after December 15, 2017, with early adoption permitted. On January 1, 2017, the Company prospectively adopted ASU 2017-01. Adoption of ASU 2017-01 has had no material effect on the Company's consolidated financial statements and footnote disclosures. All other issued and effective accounting standards during 2017 were determined to be not relevant or material to the Company. Recently Issued Accounting Standards Not Yet Adopted Other than the following, there have been no new developments to those recently issued accounting standards disclosed in the Company’s 2016 Annual Report on Form 10-K. In May 2014, the FASB issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers ("ASU 2014-09"). ASU 2014-09 supersedes nearly all existing revenue recognition guidance under GAAP. The ASU 2014-09 provides a revenue recognition five-step model to be applied to all revenue contracts with customers. In 2016, the FASB issued final amendments to ASU 2014-09 to clarify the implementation guidance for principal versus agent considerations, identifying performance obligations and the accounting for licenses of intellectual property. The core principle of ASU 2014-09 is that an entity should recognize revenue for the transfer of goods or services equal to the amount that it expects to be entitled to receive for those goods or services. ASU 2014-09 also requires additional disclosures about the nature, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments. ASU 2014-09 and 2016 final amendments are effective for annual and interim periods beginning after December 15, 2017. The Company expects to adopt the new standard on January 1, 2018. The Company is still evaluating its method of adoption (full retrospective or modified retrospective), which depends in part upon the completion of the overall assessment on the impact this guidance has on our revenue arrangements. Our assessment is expected to be completed during the third quarter of 2017. We are in the process of completing our contracts review and have applied the five-step model specified by the new guidance. The five-step model includes: (1) determination of whether a contract, an agreement between two or more parties that creates legally enforceable rights and obligations, exists; (2) identification of the performance obligations in the contract; (3) determination of the transaction price; (4) allocation of the transaction price to the performance obligations in the contract; and (5) recognition of revenue when (or as) the performance obligation is satisfied. Based on our preliminary review, while we do not expect this change to have a material impact on net sales based on current information and subject to future events and circumstances, we believe that ASU 2014-09's broad definition of variable consideration may require the Company to estimate and record certain variable payments resulting from rebates and other pricing allowances earlier than it currently does in order to properly identify the performance obligations and recognize the transaction price at the contract inception. The Company has not yet completed the process of quantifying the effects of any changes that will result from adoption. The Company is also identifying and preparing to implement changes to our accounting policies and practices, business processes, systems and controls to support the new revenue recognition and disclosure requirements. In October 2016, the FASB issued Accounting Standards Update No. 2016-16, Income Taxes (Topic 740), Intra-Entity Transfers of Assets Other Than Inventory ("ASU 2016-16"), which requires companies to account for the income tax effects of intercompany sales and transfers of assets other than inventory when the transfer occurs. Current guidance requires companies to defer the income tax effects of intercompany transfers of assets until the asset has been sold to an outside party or otherwise recognized. The amendment is to be applied using a modified retrospective approach. ASU 2016-16 is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years, with early adoption permitted. Based on current information and subject to future events and circumstances, the Company does not know whether ASU 2016-16 will have a material impact on its financial statements upon adoption. In January 2017, the FASB issued Accounting Standards Update No. 2017-04, Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment ("ASU 2017-04"), which eliminates the requirement to calculate the implied fair value of goodwill to measure a goodwill impairment charge or Step 2 of the goodwill impairment analysis. Instead, an impairment charge will be recorded based on the excess of a reporting unit's carrying amount over its fair value using Step 1 of the goodwill impairment analysis. The standard is required to be adopted for annual and interim impairment tests performed after December 15, 2019. The amendment is to be applied prospectively. Early adoption is permitted for annual and interim goodwill impairment testing dates after January 1, 2017. Based on current information and subject to future events and circumstances, the Company does not know whether ASU 2017-04 will have a material impact on its financial statements upon adoption.