XML 65 R53.htm IDEA: XBRL DOCUMENT
v3.25.1

Fair Value Measurements and Derivative Instruments (Narrative) (Details) - USD ($) $ in Millions | 3 Months Ended
--- | ---
Mar. 31, 2025 | Mar. 31, 2024
Derivative |  |
Ineffectiveness expense | $ 0.0 | $ 0.0
Foreign Exchange Contract |  |
Derivative |  |
Amount of derivative cash flow hedge to be recognized in the next 12 months | $ 0.2 |
Foreign Exchange Contract | Minimum |  |
Derivative |  |
Derivative, Term of Contract | 1 month |
Foreign Exchange Contract | Maximum |  |
Derivative |  |
Derivative, Term of Contract | 12 months |

X
- Definition Derivative, Ineffectiveness Expense + References No definition available. + Details
Name: | gti_DerivativeIneffectivenessExpense
Namespace Prefix: | gti_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 815 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480870/815-30-50-1 + Details
Name: | us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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 Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 815 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480237/815-40-50-5 + Details
Name: | us-gaap_DerivativeLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Period the derivative contract is outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
Name: | us-gaap_DerivativeTermOfContract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_ForeignExchangeContractMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |