v3.26.1
Acquisitions and Dispositions of Businesses (Dispositions and Other) (Narrative) (Details) - USD ($)
$ in Thousands
 1 Months Ended 3 Months Ended 6 Months Ended
Feb. 25, 2025
Mar. 31, 2026
Jan. 31, 2026
Dec. 31, 2025
Oct. 31, 2025
Jul. 31, 2025
Dec. 31, 2024
Jun. 30, 2026
Mar. 31, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Disposal Group, Including Discontinued Operations [Line Items]                        
Non-operating loss on sale of business               $ (5,151)   $ 371 $ (5,151) $ 371
Total impairment charges               0   0 19,029 0
Impairment of goodwill                     976  
Noncontrolling interest, decrease from redemptions or purchase of interests                 $ 16,849      
Interest expense               17,173   18,106 33,402 100,383
Mandatorily redeemable noncontrolling interest, Current       $ 6,874       6,033     6,033  
Kaplan Languages Group (KLG) [Member]                        
Disposal Group, Including Discontinued Operations [Line Items]                        
Non-operating loss on sale of business               5,200        
Total impairment charges                 19,000   19,000  
Impairment of goodwill                 1,000   1,000  
Impairment charge related to the asset group held for sale                 $ 18,000   18,000  
CSI Pharmacy Holding Company, LLC                        
Disposal Group, Including Discontinued Operations [Line Items]                        
Noncontrolling interest, decrease from redemptions or purchase of interests   $ 41,000       $ 1,800 $ 2,000          
Clarus [Member]                        
Disposal Group, Including Discontinued Operations [Line Items]                        
Noncontrolling interest, decrease from redemptions or purchase of interests     $ 1,000   $ 400              
GHC One [Member]                        
Disposal Group, Including Discontinued Operations [Line Items]                        
Mandatory redemption settlement amount $ 205,000                      
Mandatorily redeemable noncontrolling interest, Current               6,000     6,000  
Remaining GHC One and GHC Two [Member]                        
Disposal Group, Including Discontinued Operations [Line Items]                        
Mandatory redemption settlement amount               7,400     7,400  
Securities Subject to Mandatory Redemption [Member]                        
Disposal Group, Including Discontinued Operations [Line Items]                        
Interest expense                   $ (1,200)   $ (67,600)
Securities Subject to Mandatory Redemption [Member] | GHC One [Member]                        
Disposal Group, Including Discontinued Operations [Line Items]                        
Interest expense 66,200                      
Cash paid for CSI minority shares [Member] | CSI Pharmacy Holding Company, LLC                        
Disposal Group, Including Discontinued Operations [Line Items]                        
Noncontrolling interest, decrease from redemptions or purchase of interests   16,400         600          
Promissory Notes for CSI Minority Shares due 2028 [Member] | CSI Pharmacy Holding Company, LLC                        
Disposal Group, Including Discontinued Operations [Line Items]                        
Noncontrolling interest, decrease from redemptions or purchase of interests   $ 24,600                    
Interest rate   8.00%             8.00%      
Cash paid to settle a significant portion of the mandatorily redeemable noncontrolling interest [Member] | GHC One [Member]                        
Disposal Group, Including Discontinued Operations [Line Items]                        
Mandatory redemption settlement amount 186,250                      
GHC Class B Common Stock issued [Member] | GHC One [Member]                        
Disposal Group, Including Discontinued Operations [Line Items]                        
Mandatory redemption settlement amount $ 18,750                      
Promissory Note for CSI minority shares due 2026 [Member] | CSI Pharmacy Holding Company, LLC                        
Disposal Group, Including Discontinued Operations [Line Items]                        
Noncontrolling interest, decrease from redemptions or purchase of interests             $ 1,400          
Interest rate             5.50%          
Additional Amount Payable for CSI Minority Shares [Member] | CSI Pharmacy Holding Company, LLC                        
Disposal Group, Including Discontinued Operations [Line Items]                        
Noncontrolling interest, decrease from redemptions or purchase of interests       $ 100                
Interest rate       5.50%                
Education [Member]                        
Disposal Group, Including Discontinued Operations [Line Items]                        
Impairment of goodwill                     976  
Education [Member] | Kaplan Languages Group (KLG) [Member]                        
Disposal Group, Including Discontinued Operations [Line Items]                        
Non-operating loss on sale of business               $ (5,200)        
Education [Member] | Kaplan International [Member]                        
Disposal Group, Including Discontinued Operations [Line Items]                        
Impairment of goodwill                 $ 1,000   $ 976  
Graham Holdings Company [Member] | CSI Pharmacy Holding Company, LLC                        
Disposal Group, Including Discontinued Operations [Line Items]                        
Ownership percentage by parent             87.50% 93.40%     93.40%  
Graham Holdings Company [Member] | Clarus [Member]                        
Disposal Group, Including Discontinued Operations [Line Items]                        
Ownership percentage by parent         95.75%     97.50%     97.50%