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Organization, Basis of Presentation and Recent Accounting Pronouncements (Organization and Basis of Presentation) (Narrative) (Details) | Jun. 30, 2025 televisionStation automotiveDealership
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Television Broadcasting [Member] |
Number of television broadcast stations | televisionStation | 7
Automotive [Member] |
Number of Automotive Dealerships Owned | automotiveDealership | 8

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- Definition Number of television broadcast stations owned by the Company. + References No definition available. + Details
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Namespace Prefix: | ghc_
Data Type: | xbrli:integerItemType
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- Details
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Namespace Prefix: |
Data Type: | na
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- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=ghc_AutomotiveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |