Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2018	Apr. 27, 2018
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q1
Trading Symbol	ghc
Entity Registrant Name	GRAHAM HOLDINGS CO
Entity Central Index Key	0000104889
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Class A Common Stock [Member]
Entity Common Stock, Shares Outstanding		964,001
Class B Common Stock [Member]
Entity Common Stock, Shares Outstanding		4,399,736