XML 48 R36.htm IDEA: XBRL DOCUMENT
v3.25.1

Organization and Summary of Significant Accounting Policies (Details) | Mar. 31, 2025 majorProductCategory
--- | ---
Accounting Policies [Abstract] |
Number of major product categories | 2

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