Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Revenues
Education	$ 380,953	$ 377,033	$ 386,698	$ 372,975	$ 391,261	$ 386,936	$ 419,144	$ 401,006	$ 1,517,659	$ 1,598,347	$ 1,927,405
Advertising	84,517	74,198	77,437	69,221	90,707	91,597	75,494	73,104	305,373	330,902	299,076
Other	210,347	205,994	211,952	140,521	147,611	143,105	134,295	127,630	768,814	552,641	359,633
Total Operating Revenues	675,817	657,225	676,087	582,717	629,579	621,638	628,933	601,740	2,591,846	2,481,890	2,586,114
Operating Costs and Expenses
Operating	348,289	352,635	358,252	300,666	300,086	293,194	296,033	291,632	1,359,842	1,180,945	1,206,153
Selling, general and administrative	231,453	232,782	213,848	231,509	195,173	237,694	236,437	235,213	909,592	904,517	1,104,163
Depreciation of property, plant and equipment	15,984	16,002	15,871	14,652	15,717	16,097	16,045	16,761	62,509	64,620	77,906
Amortization of Intangible Assets	12,897	10,923	10,531	6,836	7,511	6,620	6,278	6,262	41,187	26,671	19,017
Impairment of goodwill and other long-lived assets	78	312	9,224	0					9,614	1,603	259,700
Total Operating Costs and Expenses	608,701	612,654	607,726	553,663	520,090	553,605	554,793	549,868	2,382,744	2,178,356	2,666,939
Income (Loss) from Operations	67,116	44,571	68,361	29,054	109,489	68,033	74,140	51,872	209,102	303,534	(80,825)
Equity in losses of affiliates, net	(4,697)	(532)	1,331	649	(7,042)	(1,008)	(891)	1,004	(3,249)	(7,937)	(697)
Interest Income	3,184	861	1,173	1,363	1,041	740	721	591	6,581	3,093	1,909
Interest expense	(8,103)	(8,619)	(9,035)	(8,129)	(10,857)	(8,614)	(7,971)	(7,948)	(33,886)	(35,390)	(32,654)
Other income (expense), net	(2,640)	1,963	4,069	849	(28,513)	(18,225)	19,000	15,096	4,241	(12,642)	(8,623)
Income (Loss) from Continuing Operations Before Income Taxes	54,860	38,244	65,899	23,786	64,118	40,926	84,999	60,615	182,789	250,658	(120,890)
(Benefit from) Provision for Income Taxes	(159,700)	13,400	23,900	2,700	27,200	7,800	23,800	22,400	(119,700)	81,200	20,500
Income (Loss) from Continuing Operations									302,489	169,458	(141,390)
Income from Discontinued Operations, Net of Tax									0	0	42,170
Net Income (Loss)	214,560	24,844	41,999	21,086	36,918	33,126	61,199	38,215	302,489	169,458	(99,220)
Net Income Attributable to Noncontrolling Interests	(382)	(60)	(3)	0	0	0	(433)	(435)	(445)	(868)	(1,435)
Net Income (Loss) Attributable to Graham Holdings Company									302,044	168,590	(100,655)
Redeemable Preferred Stock Dividends									0	0	(631)
Net income (loss) attributable to Graham Holdings Company common stockholders	214,178	24,784	41,996	21,086	36,918	33,126	60,766	37,780	302,044	168,590	(101,286)
Amounts Attributable to Graham Holdings Company Common Stockholders
Income (loss) from continuing operations									302,044	168,590	(143,456)
Income from Discontinued Operations, Net of Tax									0	0	42,170
Net income (loss) attributable to Graham Holdings Company common stockholders	$ 214,178	$ 24,784	$ 41,996	$ 21,086	$ 36,918	$ 33,126	$ 60,766	$ 37,780	$ 302,044	$ 168,590	$ (101,286)
Per Share Information Attributable to Graham Holdings Company Common Stockholders
Basic income (loss) per common share from continuing operations in dollars per share									$ 54.24	$ 29.95	$ (25.23)
Basic income per common share from discontinued operations in dollars per share									0.00	0.00	7.36
Basic net income (loss) per common share in dollars per share	$ 38.76	$ 4.45	$ 7.51	$ 3.77	$ 6.60	$ 5.90	$ 10.82	$ 6.63	$ 54.24	$ 29.95	$ (17.87)
Basic average number of common shares outstanding in shares	5,473	5,518	5,539	5,535	5,527	5,544	5,544	5,623	5,516	5,559	5,727
Diluted income (loss) per common share from continuing operations in dollars per share									$ 53.89	$ 29.80	$ (25.23)
Diluted income per common share from discontinued operations in dollars per share									0.00	0.00	7.36
Diluted net income (loss) per common share in dollars per share	$ 38.52	$ 4.42	$ 7.46	$ 3.75	$ 6.57	$ 5.87	$ 10.76	$ 6.59	$ 53.89	$ 29.80	$ (17.87)
Diluted average number of common shares outstanding in shares	5,509	5,554	5,577	5,569	5,556	5,574	5,574	5,652	5,552	5,589	5,727