XML 11 R1.htm IDEA: XBRL DOCUMENT v3.20.2
Cover
Aug. 06, 2020
Aug. 05, 2020
May 06, 2020
Cover [Abstract]      
Entity Incorporation, State or Country Code DE    
Document Type 8-K    
Document Period End Date   Aug. 05, 2020  
Entity Registrant Name GRAFTECH INTERNATIONAL LTD.    
Entity File Number 1-13888    
Entity Tax Identification Number 27-2496053    
Entity Address, Address Line One 982 Keynote Circle    
Entity Address, City or Town Brooklyn Heights    
Entity Address, State or Province OH    
Entity Address, Postal Zip Code 44131    
City Area Code 216    
Local Phone Number 676-2000    
Written Communications false    
Soliciting Material false    
Pre-commencement Tender Offer false    
Pre-commencement Issuer Tender Offer false    
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 Emerging Growth Company false    
Entity Central Index Key     0000931148
Amendment Flag     false