XML 60 R46.htm IDEA: XBRL DOCUMENT
v3.22.4

Summary of Significant Accounting Policies - Schedule Of Collective-Bargaining Arrangements (Details) - Dec. 31, 2022 | employee | salariedEmployee | hourlyEmployee
--- | --- | --- | ---
Schedule of Collective-Bargaining Arrangement [Line Items] |  |  |
Number of employees | 1,986 | 385 | 1,601
United States |  |  |
Schedule of Collective-Bargaining Arrangement [Line Items] |  |  |
Number of employees | 690 |  |
United States | International Association of Machinists and Aerospace Workers ("IAM") |  |  |
Schedule of Collective-Bargaining Arrangement [Line Items] |  |  |
Number of employees | 320 |  |
Mexico |  |  |
Schedule of Collective-Bargaining Arrangement [Line Items] |  |  |
Number of employees | 1,073 |  |
Mexico | Sindicato de Jorneleros y Obreros |  |  |
Schedule of Collective-Bargaining Arrangement [Line Items] |  |  |
Number of employees | 805 |  |
Mexico | Sindicato de trabajadores de la industria metalica y del comercio del estado de Nuevo Leon Presidente Benito Juarez Garcia C.T.M. |  |  |
Schedule of Collective-Bargaining Arrangement [Line Items] |  |  |
Number of employees | 69 |  |
Canada |  |  |
Schedule of Collective-Bargaining Arrangement [Line Items] |  |  |
Number of employees | 223 |  |
Canada | United Food & Commercial Workers Canada ("UFCW") |  |  |
Schedule of Collective-Bargaining Arrangement [Line Items] |  |  |
Number of employees | 177 |  |

X
- Definition Schedule of Collective-Bargaining Arrangement [Line Items] + References No definition available. + Details
Name: | cmt_ScheduleOfCollectiveBargainingArrangementLineItems
Namespace Prefix: | cmt_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of persons employed by the Entity + References No definition available. + Details
Name: | dei_EntityNumberOfEmployees
Namespace Prefix: | dei_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | srt_StatementGeographicalAxis=country_US
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CollectiveBargainingArrangementAxis=cmt_InternationalAssociationOfMachinistsAndAerospaceWorkersMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementGeographicalAxis=country_MX
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CollectiveBargainingArrangementAxis=cmt_SindicatoDeJornelerosYObrerosMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CollectiveBargainingArrangementAxis=cmt_SindicatoDeTrabajadoresDeLaIndustriaMetalicaYDelComercioDelEstadoDeNuevoLeonPresidenteBenitoJuarezGarciaCtmMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementGeographicalAxis=country_CA
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CollectiveBargainingArrangementAxis=cmt_UnitedFoodAndCommercialWorkersCanadaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |