Earnings Per Share (Details 1) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Schedule of Earnings Per Share, Basic and Diluted, Including Two Class Method [Line Items]
Net income attributable to Graham Holdings Company common stockholders	$ 43,145	$ 125,064	$ 181,974	$ 214,521
Less: Dividends paid-common stock outstanding and unvested restricted shares	(7,386)	(7,048)	(29,554)	(28,635)
Undistributed earnings	$ 35,759	$ 118,016	$ 152,420	$ 185,886
Percent allocated to common stockholders	99.44%	99.34%	99.44%	99.34%
Undistributed Earnings Allocated To Common Stockholders	$ 35,559	$ 117,235	$ 151,570	$ 184,657
Add: Dividends paid-common stock outstanding	7,345	7,001	29,389	28,447
Numerator for basic earnings per share	42,904	124,236	180,959	213,104
Add: Additional undistributed earnings due to dilutive stock options	2	5	7	8
Numerator for diluted earnings per share	$ 42,906	$ 124,241	$ 180,966	$ 213,112
Weighted average shares outstanding (shares)	5,285	5,302	5,285	5,354
Denominator for diluted earnings per share (shares)	5,329	5,337	5,328	5,390
Graham Holdings Company Common Stockholders:
Basic income per common share in dollars per share	$ 8.12	$ 23.43	$ 34.24	$ 39.81
Diluted income per common share in dollars per share	$ 8.05	$ 23.28	$ 33.96	$ 39.54
Stock Option Plan [Member]
Schedule of Earnings Per Share, Basic and Diluted, Including Two Class Method [Line Items]
Add: Effect of dilutive stock options (shares)	44	35	43	36