v3.25.4

Cover - USD ($) $ in Millions	12 Months Ended
Cover - USD ($) $ in Millions	Dec. 31, 2025	Feb. 06, 2026	Jun. 30, 2025
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2025
Document Transition Report	false
Entity File Number	1-13888
Entity Registrant Name	GRAFTECH INTERNATIONAL LTD.
Entity Incorporation, State	DE
Entity Tax Identification Number	27-2496053
Entity Address, Street	982 Keynote Circle
Entity Address, City	Brooklyn Heights
Entity Address, State	OH
Entity Address, Zip Code	44131
City Area Code	216
Local Phone Number	676-2000
Title of each class	Common Stock, $0.01 par value per share
Trading Symbol(s)	EAF
Name of each exchange on which registered	NYSE
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float			$ 250.3
Entity Common Stock, Shares Outstanding		25,820,110
Documents Incorporated by Reference	Portions of the definitive proxy statement (the “Proxy Statement”) to be filed with the Securities and Exchange Commission (“SEC”) relative to the registrant’s 2026 Annual Meeting of Stockholders are incorporated by reference into Part III of this Report.
Entity Central Index Key	0000931148
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2025
Document Fiscal Period Focus	FY
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GRAFTECH INTERNATIONAL LTD 10-K