Earnings Per Share (Details 1) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Schedule of Earnings Per Share, Basic and Diluted, Including Two Class Method [Line Items]
Net income attributable to Graham Holdings Company common stockholders	$ 81,748	$ 42,891
Less: Dividends paid-common stock outstanding and unvested restricted shares	(14,779)	(14,638)
Undistributed earnings	$ 66,969	$ 28,253
Percent allocated to common stockholders	99.43%	99.30%
Undistributed Earnings Allocated To Common Stockholders	$ 66,588	$ 28,057
Add: Dividends paid-common stock outstanding	14,695	14,539
Numerator for basic earnings per share	81,283	42,596
Add: Additional undistributed earnings due to dilutive stock options	3	1
Numerator for diluted earnings per share	$ 81,286	$ 42,597
Weighted average shares outstanding (shares)	5,284	5,436
Denominator for diluted earnings per share (shares)	5,326	5,473
Graham Holdings Company Common Stockholders:
Basic income per common share in dollars per share	$ 15.38	$ 7.84
Diluted income per common share in dollars per share	$ 15.26	$ 7.78
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)	42	37