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v3.23.1

Summary of Significant Accounting Policies - Advance to operators (Details) | 3 Months Ended
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Mar. 31, 2023
Accounting Policies [Abstract] |
Advance payments to operators, term | 90 days

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- Definition Term in which the Company expects advance payments to be applied by oil and gas operators against joint interest billings for its share of drilling operations + References No definition available. + Details
Name: | grnt_AdvancePaymentsToOperatorsTerm
Namespace Prefix: | grnt_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

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