Acquisitions and Dispositions of Businesses (Significant Component) (Details 3) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014
Acquisitions And Dispositions [Abstract]
Disposal Group, Not Discontinued Operation, Revenue	$ 167,093	$ 268,895
Disposal Group, Not Discontinued Operation, Operating Income (Loss)	$ (6,264)	$ (7,748)

Amount of operating income (loss) attributable to disposal group. Excludes discontinued operations.

No definition available.

Name:	ghc_DisposalGroupNotDiscontinuedOperationOperatingIncomeLoss
Namespace Prefix:	ghc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration