Earnings (Loss) Per Share (Details 1) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Schedule of Earnings (Loss) Per Share, Basic and Diluted, Including Two Class Method [Line Items]
Net income (loss) attributable to Graham Holdings Company common stockholders	$ 18,854	$ 57,081	$ (14,391)	$ 138,829
Less: Dividends paid-common stock outstanding and unvested restricted shares	(7,581)	(7,388)	(22,870)	(22,167)
Undistributed earnings (loss)	$ 11,273	$ 49,693	$ (37,261)	$ 116,662
Percent allocated to common stockholders	99.44%	99.43%	100.00%	99.43%
Undistributed Earnings (Loss) Allocated To Common Stockholders	$ 11,210	$ 49,410	$ (37,261)	$ 115,997
Add: Dividends paid-common stock outstanding	7,539	7,346	22,745	22,041
Numerator for basic earnings (loss) per share	18,749	56,756	(14,516)	138,038
Add: Additional undistributed earnings due to dilutive stock options	0	2	0	5
Numerator for diluted earnings (loss) per share	$ 18,749	$ 56,758	$ (14,516)	$ 138,043
Weighted average shares outstanding (shares)	5,196	5,285	5,235	5,285
Denominator for diluted earnings (loss) per share (shares)	5,201	5,329	5,235	5,328
Graham Holdings Company Common Stockholders:
Basic income (loss) per common share in dollars per share	$ 3.61	$ 10.74	$ (2.77)	$ 26.12
Diluted income (loss) per common share in dollars per share	$ 3.60	$ 10.65	$ (2.77)	$ 25.91
Stock Option Plan [Member]
Schedule of Earnings (Loss) Per Share, Basic and Diluted, Including Two Class Method [Line Items]
Add: Effect of dilutive stock options (shares)	5	44	0	43