Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net Income	$ 42,965	$ 21,086
Foreign currency translation adjustments:
Translation adjustments arising during the period	11,564	13,668
Unrealized gains on available-for-sale securities:
Unrealized gains for the period, net	0	9,558
Pension and other postretirement plans:
Amortization of net prior service cost included in net income	76	120
Amortization of net actuarial gain included in net income	(1,367)	(1,823)
Total pension and other postretirement plans, before tax	(1,291)	(1,703)
Cash flow hedge gain (loss)	236	(124)
Other Comprehensive Income, Before Tax	10,509	21,399
Income tax benefit (expense) related to items of other comprehensive income	303	(3,117)
Other Comprehensive Income, Net of Tax	10,812	18,282
Comprehensive Income	53,777	39,368
Comprehensive income attributable to noncontrolling interests	(74)	0
Total Comprehensive Income Attributable to Graham Holdings Company	$ 53,703	$ 39,368