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Fair Value Measurements (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2026	Mar. 31, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total impairment charges	$ 0		$ 2,235	$ 19,029	$ 2,235
Goodwill impairment charge				976
Other Asset Impairment Charges			2,200		2,200
Impairment on equity method investment	500			6,300
Impairment of cost method investments	$ 100		$ 1,486	100	$ 14,165
Kaplan Languages Group (KLG) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total impairment charges		$ 19,000		19,000
Goodwill impairment charge		1,000		1,000
Impairment charge related to the asset group held for sale		$ 18,000		$ 18,000
Graham Holdings Company [Member] \| GHC One and GHC Two [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Guaranteed Return				8.00%
Percentage of Distributions Available to Common Unit Holders				80.00%
Group of Senior Managers of GHG [Member] \| GHC One and GHC Two [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Percentage of Distributions Available to Common Unit Holders				20.00%
Group of Senior Managers of GHG [Member] \| GHC One and GHC Two [Member] \| GHC One and GHC Two [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	5.00%			5.00%
Graham Holdings Company [Member] \| GHC One and GHC Two [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Percentage of Contributed Capital				95.00%
Group of Senior Managers of GHG [Member] \| GHC One and GHC Two [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Percentage of Contributed Capital				5.00%