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Acquisitions and Dispositions of Businesses (Dispositions and Other) (Narrative) (Details) $ in Thousands	1 Months Ended		3 Months Ended
	Nov. 30, 2019 business	Mar. 31, 2019 USD ($)	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sales of businesses			$ 107	$ 189
Change in redemption value of manditorily redeemable noncontrolling interest				$ (54)
Group of Senior Managers of GHG [Member] \| GHC One [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners			5.00%
Percentage of Distributions Available to Common Unit Holders			20.00%
Graham Holdings Company [Member] \| GHC One [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Guaranteed Return			8.00%
Percentage of Distributions Available to Common Unit Holders			80.00%
Education [Member] \| Kaplan International [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of businesses disposed \| business	1
Hoover Treated Wood Products [Member] \| Manufacturing [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Change in redemption value of manditorily redeemable noncontrolling interest		$ 600
Graham Holdings Company [Member] \| Hoover Treated Wood Products [Member] \| Manufacturing [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership percentage by parent		98.01%		98.01%
Graham Holdings Company [Member] \| GHC One [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage of Contributed Capital			95.00%
Group of Senior Managers of GHG [Member] \| GHC One [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage of Contributed Capital			5.00%