Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Statement [Abstract]
Operating Revenues	$ 672,677	$ 676,087	$ 1,332,113	$ 1,258,804
Operating Costs and Expenses [Abstract]
Operating	440,655	381,747	805,806	707,434
Selling, General and Administrative Expenses	141,378	208,973	366,423	434,262
Depreciation of property, plant and equipment	13,619	15,871	28,261	30,523
Amortization of intangible assets	11,399	10,531	21,783	17,367
Impairment of goodwill and other long-lived assets	0	9,224	0	9,224
Total Operating Costs and Expenses	607,051	626,346	1,222,273	1,198,810
Income from Operations	65,626	49,741	109,840	59,994
Equity in earnings of affiliates, net	931	1,331	3,510	1,980
Interest income	1,901	1,173	3,273	2,536
Interest expense	(17,165)	(9,035)	(25,236)	(17,164)
Debt extinguishment costs	(11,378)	0	(11,378)	0
Non-operating pension and postretirement benefit income, net	23,041	18,620	44,427	37,421
Loss on marketable equity securities, net	(2,554)	0	(16,656)	0
Other income, net	2,333	4,069	11,520	4,918
Income Before Income Taxes	62,735	65,899	119,300	89,685
Provision for Income Taxes	16,100	23,900	29,700	26,600
Net Income	46,635	41,999	89,600	63,085
Net Income Attributable to Noncontrolling Interests	(69)	(3)	(143)	(3)
Net Income Attributable to Graham Holdings Company Common Stockholders	$ 46,566	$ 41,996	$ 89,457	$ 63,082
Per Share Information Attributable to Graham Holdings Company Common Stockholders
Basic net income per common share in dollars per share	$ 8.69	$ 7.51	$ 16.52	$ 11.29
Basic average number of common shares outstanding in shares	5,325	5,539	5,380	5,537
Diluted net income per common share in dollars per share	$ 8.63	$ 7.46	$ 16.40	$ 11.21
Diluted average number of common shares outstanding in shares	5,362	5,577	5,417	5,573