Organization, Operations and Basis of Presentation	9 Months Ended
Organization, Operations and Basis of Presentation	Sep. 30, 2018
Accounting Policies [Abstract]
Organization, Operations and Basis of Presentation	Organization, Operations and Basis of Presentation Description of Business AdvanSix Inc. (“AdvanSix”, the “Company”, "we" or "our") is an integrated manufacturer of Nylon 6, a polymer resin which is a synthetic material used by our customers to produce engineered plastics, fibers, filaments and films that, in turn, are used in such end-products as automotive and electronic components, carpets, sports apparel, fishing nets and food and industrial packaging. As a result of our backward integration and the configuration of our manufacturing facilities, we also sell a variety of other products, all of which are produced as part of our integrated Nylon 6 resin manufacturing process including caprolactam, ammonium sulfate fertilizers, acetone and other chemical intermediates. Separation from Honeywell On October 1, 2016, Honeywell International Inc. (“Honeywell”) completed the separation of AdvanSix. The separation was completed by Honeywell distributing (the “Distribution”) all of the then outstanding shares of common stock of AdvanSix on October 1, 2016 (the “Distribution Date”) through a dividend in kind of AdvanSix common stock, par value $0.01, to holders of Honeywell common stock as of the close of business on the record date of September 16, 2016 who held their shares through the Distribution Date (the “Spin-Off”). Each Honeywell stockholder who held their shares through the Distribution Date received one share of AdvanSix common stock for every 25 shares of Honeywell common stock held at the close of business on the record date of September 16, 2016. We filed our Form 10 describing the Spin-Off with the Securities and Exchange Commission (the “SEC”), which was declared effective by the SEC on September 8, 2016 (the “Form 10”). On October 3, 2016, AdvanSix stock began “regular-way” trading on the New York Stock Exchange under the “ASIX” stock symbol. Basis of Presentation The Condensed Consolidated Financial Statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim financial information and with the instructions to Rule 10-01 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. In the opinion of management, the accompanying unaudited Condensed Consolidated Financial Statements contain all adjustments, consisting of only normal recurring adjustments, necessary for a fair statement of the Company's financial position as of September 30, 2018, and its results of operations for the three and nine months ended September 30, 2018 and 2017, and cash flows for the nine months ended September 30, 2018 and 2017. The Condensed Consolidated Balance Sheets at December 31, 2017 were derived from audited annual financial statements but do not contain all of the footnote disclosures from the annual financial statements. The results of operations of any interim period are not necessarily indicative of the results of operations to be expected for the full fiscal year. These financial statements should be read in conjunction with the Company’s Annual Report on Form 10-K (the "2017 Form 10-K") for the year ended December 31, 2017. All intercompany transactions have been eliminated. Certain prior period amounts have been reclassified for consistency with the current period presentation. It is our practice to establish actual quarterly closing dates using a predetermined fiscal calendar, which requires our businesses to close their books on a Saturday in order to minimize the potentially disruptive effects of quarterly closing on our business processes. Historically, the effects of this practice were generally not significant to reported results for any quarter and only existed within a reporting year. In the event that differences in actual closing dates are material to year-over-year comparisons of quarterly or year-to-date results, we will provide the appropriate disclosures. Our actual closing dates for the three and nine months ended September 30, 2018 and 2017 were September 29, 2018 and September 30, 2017, respectively. Liabilities to creditors to whom we have issued checks that remained outstanding at September 30, 2018, and December 31, 2017 aggregated $8.2 million and $8.5 million, respectively, and were included in Cash and cash equivalents and Accounts payable in the Condensed Consolidated Balance Sheets. On May 4, 2018, the Company announced that its Board of Directors authorized a share repurchase program of up to $75 million of the Company’s common stock. Repurchases may be made from time to time on the open market, including through the use of trading plans intended to qualify under Rule 10b5-1 of the Securities Exchange Act of 1934, as amended (the "Exchange Act"). The size and timing of these repurchases will depend on pricing, market and economic conditions, legal and contractual requirements and other factors. The repurchase program has no expiration date and may be modified, suspended or discontinued at any time. The Company had approximately 30 million shares of common stock outstanding as of September 30, 2018. The par value of the shares repurchased is applied to Treasury stock and the excess of the purchase price over par value is applied to Additional paid-in capital. As of September 30, 2018, the Company had repurchased 545,282 shares of common stock for an aggregate of $19.7 million under the currently authorized program at a weighted average market price of $36.06 per share. As of September 30, 2018, $55.3 million remained available for share repurchases under the currently authorized program.