Acquisitions and Dispositions of Businesses (Narrative) (Details)			1 Months Ended									12 Months Ended
	Jul. 05, 2022 USD ($) business	Jun. 14, 2021 USD ($)	Dec. 31, 2023 USD ($) business automotiveDealership	Jul. 31, 2023 business	Jan. 31, 2023 business	Nov. 30, 2022 USD ($)	Aug. 31, 2022 business	May 31, 2022 business	Dec. 31, 2021 USD ($) business	Nov. 30, 2021 business	Mar. 31, 2021 USD ($)	Dec. 31, 2023 USD ($) business automotiveDealership	Dec. 31, 2022 USD ($) business	Dec. 31, 2021 USD ($) business	Sep. 30, 2023 USD ($)	Jul. 31, 2022	Dec. 28, 2021 USD ($)	Feb. 28, 2021
Business Acquisition [Line Items]
Number of businesses acquired | business												5	7	6
Cost of acquisition												$ 83,300,000	$ 143,200,000	$ 392,400,000
Floor plan payable			$ 148,300,000									148,300,000	69,756,000
Payments to Acquire Businesses, Net of Cash Acquired												78,149,000	130,106,000	351,882,000
Acquisition-related costs			1,200,000						$ 3,000,000			1,200,000	1,700,000	3,000,000
Goodwill expected to be deductible for income tax purposes			45,000,000						$ 80,600,000			45,000,000	39,700,000	80,600,000
Revenues of acquired companies since acquisition date												45,200,000
Operating income of acquired companies since acquisition date												2,200,000
Net gain on sale of businesses												15,618,000	22,679,000	3,789,000
Interest expense												63,301,000	54,403,000	33,943,000
Change in redemption value of redeemable noncontrolling interests												(14,923,000)	(5,780,000)	549,000
Finance Lease, Liability, Current			17,357,000									17,357,000	8,697,000
Finance Lease, Right-of-Use Asset			22,831,000									22,831,000	13,835,000
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests												14,965,000	1,200,000	$ 3,508,000
Leaf Group [Member]
Business Acquisition [Line Items]
Cost of acquisition		$ 308,600,000
Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed Stock Compensation Liabilities Assumed		$ 9,200,000
Automotive [Member]
Business Acquisition [Line Items]
Finance Lease, Liability, Current			10,900,000									10,900,000	5,400,000
Finance Lease, Right-of-Use Asset			10,900,000									$ 10,900,000	$ 5,400,000
CSI Pharmacy Holding Company, LLC [Member]
Business Acquisition [Line Items]
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests			20,000,000			$ 1,200,000
Promissory Note for CSI Minority Shares | CSI Pharmacy Holding Company, LLC [Member]
Business Acquisition [Line Items]
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests			$ 15,000,000
Interest rate			8.00%									8.00%
Cash Paid for CSI Minority Shares | CSI Pharmacy Holding Company, LLC [Member]
Business Acquisition [Line Items]
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests			$ 5,000,000
Group of Senior Managers of GHG [Member] | GHC One [Member]
Business Acquisition [Line Items]
Percentage of Distributions Available to Common Unit Holders												20.00%
Graham Holdings Company [Member] | GHC One [Member]
Business Acquisition [Line Items]
Guaranteed Return												8.00%
Percentage of Distributions Available to Common Unit Holders												80.00%
Education [Member]
Business Acquisition [Line Items]
Number of businesses acquired | business										1				2
Manufacturing [Member] | Hoover Treated Wood Products [Member]
Business Acquisition [Line Items]
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests											$ 3,500,000
Graham Healthcare Group [Member]
Business Acquisition [Line Items]
Number of businesses acquired | business			1		2		2	2	2			3	5	2
Graham Healthcare Group [Member] | Weiss [Member]
Business Acquisition [Line Items]
Percentage of interest acquired									50.10%					50.10%
Redeemable Noncontrolling Interest									$ 6,600,000					$ 6,600,000
Graham Healthcare Group [Member] | Applied Behavior Analysis clinics
Business Acquisition [Line Items]
Percentage of interest acquired																100.00%
Graham Healthcare Group [Member] | Maximum [Member] | Weiss [Member]
Business Acquisition [Line Items]
Percentage of Shares Eligible to be Redeemed			10.00%						10.00%			10.00%		10.00%
Graham Healthcare Group [Member] | Maximum [Member] | CSI Pharmacy Holding Company, LLC [Member]
Business Acquisition [Line Items]
Percentage of Shares Eligible to be Redeemed			50.00%									50.00%
Other Businesses [Member]
Business Acquisition [Line Items]
Number of businesses acquired | business				1								1		1
Automotive [Member]
Business Acquisition [Line Items]
Number of businesses acquired | business	2											1	2	1
Number of Stores | automotiveDealership			8									8
Automotive [Member] | Auto dealerships [Member]
Business Acquisition [Line Items]
Floor plan payable	$ 10,900,000														$ 2,200,000
Amount Borrowed to Finance Business Acquisition	$ 77,400,000														$ 37,000,000
Automotive [Member] | Ford auto dealership [Member]
Business Acquisition [Line Items]
Floor plan payable																	$ 16,600,000
Amount Borrowed to Finance Business Acquisition																	$ 22,500,000
Securities Subject to Mandatory Redemption [Member] | Graham Healthcare Group [Member]
Business Acquisition [Line Items]
Interest expense												$ 10,100,000	$ 16,500,000	$ 4,100,000
Graham Holdings Company [Member] | Weiss [Member]
Business Acquisition [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent			50.10%									50.10%
Graham Holdings Company [Member] | CSI Pharmacy Holding Company, LLC [Member]
Business Acquisition [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent			86.70%						75.00%			86.70%	76.50%	75.00%
Graham Holdings Company [Member] | Manufacturing [Member] | Hoover Treated Wood Products [Member]
Business Acquisition [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent			100.00%									100.00%						98.01%
GHC One [Member] | Group of Senior Managers of GHG [Member] | GHC One [Member]
Business Acquisition [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners			5.00%									5.00%
Group of Senior Managers of GHG [Member] | GHC One [Member]
Business Acquisition [Line Items]
Percentage of Contributed Capital												5.00%
Graham Holdings Company [Member] | GHC One [Member]
Business Acquisition [Line Items]
Percentage of Contributed Capital												95.00%