XML 44 R33.htm IDEA: XBRL DOCUMENT
v3.22.1

Organization And Summary Of Significant Accounting Policies (Details) | Mar. 31, 2022 major_product_categories | Dec. 31, 2021 | Apr. 26, 2018 $ / shares shares
--- | --- | --- | ---
Accounting Policies [Abstract] |  |  |
Shares, Issued | shares |  |  | 38,097,525
Sale of Stock, Price Per Share | $ / shares |  |  | $ 15.00
Number of major product categories | major_product_categories | 2 |  |
GrafTech International Ltd | Brookfield |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |
Equity Method Investment, Ownership Percentage | 24.60% | 24.30% |

X
- Definition Number of Major Product Categories + References No definition available. + Details
Name: | gti_NumberofMajorProductCategories
Namespace Prefix: | gti_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_AccountingPoliciesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571 + Details
Name: | us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Per share amount received by subsidiary or equity investee for each share of common stock issued or sold in the stock transaction. + References No definition available. + Details
Name: | us-gaap_SaleOfStockPricePerShare
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of shares of stock issued as of the balance sheet date, including shares that had been issued and were previously outstanding but which are now held in the treasury. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=123467817&loc=d3e21463-112644 + Details
Name: | us-gaap_SharesIssued
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | srt_ConsolidatedEntitiesAxis=gti_GrafTechInternationalLtdMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=gti_BrookfieldMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |