Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Net Income	$ 39,683	$ 78,054	$ 268,244	$ 63,025
Foreign currency translation adjustments:
Translation adjustments arising during the period	(16,033)	20,430	(15,352)	(541)
Pension and other postretirement plans:
Amortization of net prior service cost included in net income	793	671	2,377	2,010
Amortization of net actuarial (gain) loss included in net income	(1,066)	304	(4,419)	914
Total pension and other postretirement plans, before tax	(273)	975	(2,042)	2,924
Cash flow hedges gain (loss)	169	157	803	(1,564)
Other Comprehensive (Loss) Income, Before Tax	(16,137)	21,562	(16,591)	819
Income tax benefit (expense) related to items of other comprehensive (loss) income	11	(299)	342	(431)
Other Comprehensive (Loss) Income, Net of Tax	(16,126)	21,263	(16,249)	388
Comprehensive Income	23,557	99,317	251,995	63,413
Comprehensive (income) loss attributable to noncontrolling interests	(97)	(439)	(850)	199
Total Comprehensive Income Attributable to Graham Holdings Company	$ 23,460	$ 98,878	$ 251,145	$ 63,612