XML 15 R1.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Cover Page - USD ($)
 12 Months Ended
Dec. 31, 2019
Feb. 21, 2020
Jun. 29, 2018
Document Type 10-K    
Document Annual Report true    
Document Period End Date Dec. 31, 2019    
Document Transition Report false    
Entity File Number 001-06714    
Entity Registrant Name Graham Holdings Co    
Entity Incorporation, State or Country Code DE    
Entity Tax Identification Number 53-0182885    
Entity Address, Address Line One 1300 North 17th Street    
Entity Address, City or Town Arlington    
Entity Address, State or Province VA    
Entity Address, Postal Zip Code 22209    
City Area Code 703    
Local Phone Number 345-6300    
Title of 12(b) Security Class B Common Stock, par value$1.00 per share    
Trading Symbol  GHC    
Security Exchange Name NYSE    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Large Accelerated Filer    
Entity Small Business false    
Entity Emerging Growth Company false    
Entity Shell Company false    
Entity Public Float     $ 3,000,000,000
Documents Incorporated by Reference [Text Block]
Documents partially incorporated by reference:
Definitive Proxy Statement for the registrant’s 2020 Annual Meeting of Stockholders
(incorporated in Part III to the extent provided in Items 10, 11, 12, 13 and 14 hereof). 
    
Amendment Flag false    
Current Fiscal Year End Date --12-31    
Document Fiscal Year Focus 2019    
Document Fiscal Period Focus FY    
Entity Central Index Key 0000104889    
Class A Common Stock [Member]      
Entity Common Stock, Shares Outstanding (in shares)   964,001  
Class B Common Stock [Member]      
Entity Common Stock, Shares Outstanding (in shares)   4,348,236