Earnings Per Share (Details 1) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Schedule of Earnings Per Share, Basic and Diluted, Including Two Class Method [Line Items]
Net income attributable to Graham Holdings Company common stockholders	$ 42,891	$ 21,086
Less: Dividends paid-common stock outstanding and unvested restricted shares	(14,638)	(14,202)
Undistributed earnings	$ 28,253	$ 6,884
Percent allocated to common stockholders	99.30%	99.04%
Undistributed Earnings Allocated To Common Stockholders	$ 28,057	$ 6,818
Add: Dividends paid-common stock outstanding	14,539	14,066
Numerator for basic earnings per share	42,596	20,884
Add: Additional undistributed earnings due to dilutive stock options	1	0
Numerator for diluted earnings per share	$ 42,597	$ 20,884
Weighted average shares outstanding (shares)	5,436	5,535
Denominator for diluted earnings per share (shares)	5,473	5,569
Graham Holdings Company Common Stockholders:
Basic income per common share in dollars per share	$ 7.84	$ 3.77
Diluted income per common share in dollars per share	$ 7.78	$ 3.75
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)	37	34