Organization And Summary Of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2020
Accounting Policies [Abstract]
Organization And Summary Of Significant Accounting Policies	Organization and Summary of Significant Accounting Policies A. Organization GrafTech International Ltd. (the “Company”) is a leading manufacturer of high quality graphite electrode products essential to the production of electric arc furnace ("EAF") steel and other ferrous and non-ferrous metals. References herein to "GrafTech" “we,” “our,” or “us” refer collectively to GrafTech International Ltd. and its subsidiaries. On August 15, 2015, we became an indirect wholly owned subsidiary of Brookfield Asset Management Inc. (together with its affiliates "Brookfield"). In April 2018, we completed our initial public offering ("IPO") of 38,097,525 shares of our common stock held by Brookfield at a price of $15.00 per share. We did not receive any proceeds related to the IPO. Our common stock is listed on the NYSE under the symbol “EAF.” Brookfield owns approximately 74% of our outstanding common stock as of December 31, 2019. The Company’s only reportable segment, Industrial Materials, is comprised of our two major product categories: graphite electrodes and petroleum needle coke products. Needle coke is the key raw material used in the production of graphite electrodes. The Company's vision is to provide highly engineered graphite electrode services, solutions and products to EAF operators. B. Basis of Presentation The interim condensed consolidated financial statements are unaudited; however, in the opinion of management, they have been prepared in accordance with Rule 10-01 of Regulation S-X and in accordance with accounting principles generally accepted in the United States of America (“GAAP”). The December 31, 2019 financial position data included herein was derived from the audited consolidated financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2019 ("Annual Report on Form 10-K") filed on February 21, 2020, but does not include all disclosures required by GAAP in audited financial statements. These interim condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements, including the accompanying notes, contained in our Annual Report on Form 10-K. The unaudited condensed consolidated financial statements reflect all adjustments (all of which are of a normal, recurring nature) which management considers necessary for a fair statement of financial position, results of operations, comprehensive income and cash flows for the interim periods presented. The results for the interim periods are not necessarily indicative of results which may be expected for any other interim period or for the full year. C. New Accounting Standards Recently Adopted Accounting Standards In January 2017, the FASB issued ASU No. 2017‑04, Intangibles‑Goodwill and Other (Topic 350). This guidance was issued to simplify the accounting for goodwill impairment. The guidance removes the second step of the goodwill impairment test, which requires that a hypothetical purchase price allocation be performed to determine the amount of impairment, if any. Under this new guidance, a goodwill impairment charge will be based on the amount by which a reporting unit’s carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. This ASU No. 2017‑04 is effective beginning January 1, 2020 with early adoption permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. The Company adopted ASU No. 2017‑04 on January 1, 2020, with no impact to our financial position, results of operations or cash flows. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments–Credit Losses (Topic 326), which introduces the Current Expected Credit Losses ("CECL") accounting model. CECL requires earlier recognition of credit losses, while also providing additional transparency about credit risk. CECL utilizes a lifetime expected credit loss measurement objective for the recognition of credit losses at the time the financial asset is originated or acquired. The expected credit losses are adjusted each period for changes in expected lifetime credit losses. ASU No. 2016-13 is effective for the Company on January 1, 2020. The adoption of ASU No. 2016-13 resulted in a cumulative-effect adjustment of $2.0 million included as an adjustment to Accounts receivable reserve and to retained earnings on January 1, 2020.