Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement of Comprehensive Income [Abstract]
Net (Loss) Income	$ 18,862	$ 57,195	$ (15,029)	$ 138,897
Foreign currency translation adjustments:
Translation adjustments arising during the period	16,405	(11,104)	(20,971)	(1,071)
Pension and other postretirement plans:
Amortization of net prior service cost (credit) included in net income (loss)	668	(931)	1,339	(2,278)
Amortization of net actuarial loss (gain) included in net income (loss)	390	(475)	610	(1,023)
Total pension and other postretirement plans, before tax	1,058	(1,406)	1,949	(3,301)
Cash flow hedges (loss) gain	(143)	40	(1,721)	(427)
Other Comprehensive Income (Loss), Before Tax	17,320	(12,470)	(20,743)	(4,799)
Income tax (expense) benefit related to items of other comprehensive income (loss)	(252)	375	(132)	994
Other Comprehensive Income (Loss), Net of Tax	17,068	(12,095)	(20,875)	(3,805)
Comprehensive Income (Loss)	35,930	45,100	(35,904)	135,092
Comprehensive (income) loss attributable to noncontrolling interests	(8)	(114)	638	(68)
Total Comprehensive Income (Loss) Attributable to Graham Holdings Company	$ 35,922	$ 44,986	$ (35,266)	$ 135,024