Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating Revenues
Operating Revenues	$ 712,455	$ 732,257
Operating Costs and Expenses
Selling, general and administrative	175,861	177,152
Depreciation of property, plant and equipment	16,545	16,704
Amortization of intangible assets	13,937	14,165
Impairment of goodwill and other long-lived assets	1,047	16,401
Total Operating Costs and Expenses	678,611	724,172
Income from Operations	33,844	8,085
Equity in earnings (losses) of affiliates, net	13,428	(1,547)
Interest income	890	1,151
Interest expense	(8,448)	(7,678)
Non-operating pension and postretirement benefit income, net	28,787	18,403
Gain (loss) on marketable equity securities, net	79,214	(100,393)
Other income, net	6,320	2,688
Income (Loss) Before Income Taxes	154,035	(79,291)
Provision for (Benefit from) Income Taxes	41,400	(45,400)
Net Income (Loss)	112,635	(33,891)
Net (Income) Loss Attributable to Noncontrolling Interests	(185)	646
Net Income (Loss) Attributable to Graham Holdings Company Common Stockholders	$ 112,450	$ (33,245)
Per Share Information Attributable to Graham Holdings Company Common Stockholders
Basic income (loss) per common share (in usd per share)	$ 22.49	$ (6.32)
Basic average number of common shares outstanding (in shares)	4,967	5,274
Diluted net income (loss) per common share (in USD per share)	$ 22.44	$ (6.32)
Diluted average number of common shares outstanding (in shares)	4,977	5,274
Services [Member]
Operating Revenues
Operating Revenues	$ 483,669	$ 516,637
Operating Costs and Expenses
Cost of services and goods	292,434	333,049
Goods [Member]
Operating Revenues
Operating Revenues	228,786	215,620
Operating Costs and Expenses
Cost of services and goods	$ 178,787	$ 166,701