Acquisitions and Dispositions of Businesses (Dispositions and Other) (Narrative) (Details) - USD ($) $ in Thousands		1 Months Ended						3 Months Ended
	Feb. 25, 2025	Mar. 31, 2026	Jan. 31, 2026	Dec. 31, 2025	Oct. 31, 2025	Jul. 31, 2025	Dec. 31, 2024	Mar. 31, 2026	Mar. 31, 2025
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total impairment charges								$ 19,029	$ 0
Impairment of goodwill								976
Noncontrolling interest, decrease from redemptions or purchase of interests								16,849
Interest expense								16,229	82,277
Mandatorily redeemable noncontrolling interest, Current		$ 6,033		$ 6,874				6,033
Kaplan Languages Group (KLG) [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total impairment charges								19,000
Impairment of goodwill								1,000
Impairment charge related to the asset group held for sale								18,000
Valuation allowance on assets held for sale		16,600						16,600
Disposal Group, Held-for-Sale, Not Discontinued Operations [Member] | Kaplan Languages Group (KLG) [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Valuation allowance on assets held for sale		16,587						16,587
CSI Pharmacy Holding Company, LLC
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Noncontrolling interest, decrease from redemptions or purchase of interests		41,000				$ 1,800	$ 2,000
Clarus [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Noncontrolling interest, decrease from redemptions or purchase of interests			$ 1,000		$ 400
GHC One [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, 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]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Mandatory redemption settlement amount		7,600						$ 7,600
Securities Subject to Mandatory Redemption [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Interest expense									$ (66,400)
Securities Subject to Mandatory Redemption [Member] | GHC One [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Interest expense	66,200
Cash paid for CSI minority shares [Member] | CSI Pharmacy Holding Company, LLC
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, 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
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, 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]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Mandatory redemption settlement amount	186,250
GHC Class B Common Stock issued [Member] | GHC One [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, 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
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, 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
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Noncontrolling interest, decrease from redemptions or purchase of interests				$ 100
Interest rate				5.50%
Education [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment of goodwill								$ 976
Education [Member] | Kaplan International [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment of goodwill								$ 976
Graham Holdings Company [Member] | CSI Pharmacy Holding Company, LLC
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership percentage by parent		93.40%					87.50%	93.40%
Graham Holdings Company [Member] | Clarus [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership percentage by parent		97.50%			95.75%			97.50%