Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Operating Revenues	$ 716,982	$ 738,820	$ 2,102,110	$ 2,168,621
Operating Costs and Expenses [Abstract]
Operating	477,960	518,207	1,418,267	1,454,776
Selling, general and administrative	164,231	175,050	499,069	516,276
Depreciation of property, plant and equipment	18,481	15,351	58,098	42,758
Amortization of intangible assets	14,150	13,572	42,642	39,512
Impairment of goodwill and other long-lived assets	1,916	372	29,828	1,065
Total Operating Costs and Expenses	676,738	722,552	2,047,904	2,054,387
Income from Operations	40,244	16,268	54,206	114,234
Equity in earnings of affiliates, net	4,092	4,683	3,727	7,829
Interest income	890	1,474	2,995	4,753
Interest expense	(7,247)	(6,776)	(22,302)	(22,587)
Non-operating pension and postretirement benefit income, net	10,489	19,556	41,028	51,737
Gain (loss) on marketable equity securities, net	59,364	17,404	(1,139)	49,261
Other income, net	222	5,556	11,010	36,135
Income Before Income Taxes	108,054	58,165	89,525	241,362
Provision for Income Taxes	30,000	15,200	26,500	59,500
Net Income	78,054	42,965	63,025	181,862
Net (Income) Loss Attributable to Noncontrolling Interests	(439)	180	199	112
Net Income Attributable to Graham Holdings Company Common Stockholders	$ 77,615	$ 43,145	$ 63,224	$ 181,974
Per Share Information Attributable to Graham Holdings Company Common Stockholders
Basic net income per common share in dollars per share	$ 15.25	$ 8.12	$ 12.15	$ 34.24
Basic average number of common shares outstanding in shares	5,060	5,285	5,176	5,285
Diluted net income per common share in dollars per share	$ 15.22	$ 8.05	$ 12.11	$ 33.96
Diluted average number of common shares outstanding in shares	5,072	5,329	5,192	5,328