XML 101 R81.htm IDEA: XBRL DOCUMENT
v3.22.0.1

Fair Value Measurements And Derivative Instruments (Schedule Of Realized (Gains) Losses On Derivatives Recognized In Statement Of Operations) (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
Derivatives designated as cash flow hedges: | Commodity Forward Derivatives | Cost of sales |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Amount of (Gain)/Loss Recognized | $ 6,440 | $ (4,134) | $ (8,892)
Derivatives designated as cash flow hedges: | Interest rate swap | Interest expense (income) |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Amount of (Gain)/Loss Recognized | 1,846 | 4,390 | (1,050)
Derivatives not designated as hedges: | Interest rate swap | Interest expense (income) |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Amount of (Gain)/Loss Recognized | 866 | 0 | 0
Derivatives not designated as hedges: | Interest rate swap | Interest expense (income) | host financial instrument |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Amount of (Gain)/Loss Recognized | 2,807 | 0 | 0
Derivatives not designated as hedges: | Foreign currency derivatives | Cost of sales, Other (income) expense, net |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Amount of (Gain)/Loss Recognized | 3,895 | (2,671) | (506)
Derivatives not designated as hedges: | Commodity Contract | Cost of sales |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Amount of (Gain)/Loss Recognized | $ (1,399) | $ (530) | $ (223)

X
- Definition Amount of increase (decrease) in the fair value of derivatives recognized in the income statement. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=125515794&loc=SL5618551-113959 + Details
Name: | us-gaap_DerivativeGainLossOnDerivativeNet
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 No definition available. + Details
Name: | us-gaap_DerivativesFairValueLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_HedgingDesignationAxis=us-gaap_DesignatedAsHedgingInstrumentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_IncomeStatementLocationAxis=us-gaap_CostOfSalesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_IncomeStatementLocationAxis=us-gaap_InterestExpenseMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_HedgingDesignationAxis=us-gaap_NondesignatedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=gti_HostFinancialInstrumentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_IncomeStatementLocationAxis=gti_CostOfGoodSoldOtherExpenseIncomeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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