Organization, Operations and Basis of Presentation	6 Months Ended
Organization, Operations and Basis of Presentation	Jun. 30, 2019
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. 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 June 30, 2019, and its results of operations and cash flows for the three and six months ended June 30, 2019 and 2018. The Condensed Consolidated Balance Sheet at December 31, 2018 was derived from audited annual financial statements but does 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 for the year ended December 31, 2018 (the "2018 Form 10-K"). 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 six months ended June 30, 2019 and 2018 were June 29, 2019 and June 30, 2018, respectively. Liabilities to creditors to whom we have issued checks that remained outstanding at June 30, 2019 and December 31, 2018 aggregated $6.7 million and $7.7 million, respectively, and were included in Cash and cash equivalents and Accounts payable in the Condensed Consolidated Balance Sheets. The Company submitted a business interruption insurance claim related to the first quarter 2018 weather event and recorded a benefit of $6.6 million and $2.3 million to Cost of goods sold in the first and second quarters of 2019, respectively. The business interruption claim has been closed with a total recorded benefit of approximately of $12 million. On May 4, 2018, the Company announced that its Board of Directors (the “Board”) authorized a share repurchase program of up to $75 million of the Company’s common stock. On February 22, 2019, the Company announced that the Board authorized a share repurchase program of up to an additional $75 million of the Company's common stock, which was in addition to the remaining capacity available under the May 2018 share repurchase program. 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 share repurchase program has no expiration date and may be modified, suspended or discontinued at any time. 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 June 30, 2019, the Company had repurchased 2,555,713 shares of common stock for an aggregate of $77.7 million at a weighted average market price of $30.40 per share. As of June 30, 2019, $72.3 million remained available for share repurchases under the current authorization.