Summary of Quarterly Operating Results and Comprehensive Income (Unaudited) (Quarterly Results) (Details 1) (USD $) Share data in Thousands, except Per Share data, unless otherwise specified	3 Months Ended									12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013		Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating Revenues
Education	$ 551,381,000	$ 543,918,000	$ 542,964,000	$ 522,154,000	$ 550,618,000	$ 543,599,000		$ 544,878,000	$ 524,639,000	$ 2,160,417,000	$ 2,163,734,000	$ 2,184,532,000
Subscriber	184,035,000	183,161,000	187,723,000	191,128,000	186,297,000	190,302,000		192,273,000	186,790,000	746,047,000	755,662,000	732,370,000
Advertising	101,271,000	81,583,000	82,475,000	78,247,000	87,692,000	73,549,000		79,898,000	69,122,000	343,576,000	310,261,000	337,621,000
Other	88,656,000	90,209,000	61,249,000	45,012,000	42,635,000	48,651,000	[1]	50,103,000	36,865,000	285,126,000	178,254,000	118,063,000
Total Operating Revenues	925,343,000	898,871,000	874,411,000	836,541,000	867,242,000	856,101,000		867,152,000	817,416,000	3,535,166,000	3,407,911,000	3,372,586,000
Operating Costs and Expenses
Operating	391,348,000	398,922,000	395,627,000	376,463,000	372,471,000	393,010,000	[1]	392,500,000	374,516,000	1,562,360,000	1,532,497,000	1,535,237,000
Selling, general and administrative	319,854,000	358,189,000	322,240,000	325,275,000	331,814,000	327,062,000		318,731,000	333,894,000	1,325,558,000	1,311,501,000	1,317,494,000
Depreciation of property, plant and equipment	45,366,000	53,074,000	51,989,000	53,217,000	58,924,000	54,672,000		56,849,000	58,910,000	203,646,000	229,355,000	240,139,000
Amortization of intangible assets	5,251,000	7,405,000	2,995,000	2,717,000	3,359,000	2,468,000		2,950,000	3,362,000	18,368,000	12,139,000	19,510,000
Impairment of intangible and other long-lived assets	17,302,000	0	0	0	3,250,000	0		0	0	25,100,000	3,300,000
Impairment of goodwill and other long-lived assets										17,302,000	3,250,000	111,593,000
Total Operating Costs and Expenses	779,121,000	817,590,000	772,851,000	757,672,000	769,818,000	777,212,000		771,030,000	770,682,000	3,127,234,000	3,088,742,000	3,223,973,000
Income from Operations	146,222,000	81,281,000	101,560,000	78,869,000	97,424,000	78,889,000		96,122,000	46,734,000	407,932,000	319,169,000	148,613,000
Equity in earnings of affiliates, net	202,000	4,613,000	91,503,000	4,052,000	37,000	5,892,000		3,868,000	3,418,000	100,370,000	13,215,000	14,086,000
Interest income	367,000	529,000	641,000	599,000	590,000	642,000		522,000	510,000	2,136,000	2,264,000	3,393,000
Interest expense	(9,879,000)	(9,330,000)	(8,557,000)	(8,820,000)	(8,838,000)	(9,221,000)		(9,048,000)	(8,960,000)	(36,586,000)	(36,067,000)	(35,944,000)
Other income (expense), net	387,346,000	64,526,000	268,114,000	133,273,000	(14,920,000)	8,110,000		(12,858,000)	(4,083,000)	853,259,000	(23,751,000)	(5,456,000)
Income from Continuing Operations Before Income Taxes	524,258,000	141,619,000	453,261,000	207,973,000	74,293,000	84,312,000		78,606,000	37,619,000	1,327,111,000	274,830,000	124,692,000
Provision for Income Taxes	191,900,000	58,200,000	78,600,000	77,400,000	24,100,000	29,900,000		31,700,000	15,800,000	406,100,000	101,500,000	73,400,000
Income from Continuing Operations	332,358,000	83,419,000	374,661,000	130,573,000	50,193,000	54,412,000		46,906,000	21,819,000	921,011,000	173,330,000	51,292,000
Income (Loss) from Discontinued Operations, Net of Tax	2,308,000	(6,980,000)	375,189,000	1,732,000	106,335,000	(23,988,000)		(1,772,000)	(16,560,000)	372,249,000	64,015,000	80,895,000
Net Income	334,666,000	76,439,000	749,850,000	132,305,000	156,528,000	30,424,000		45,134,000	5,259,000	1,293,260,000	237,345,000	132,187,000
Net (Income) Loss Attributable to Noncontrolling Interests	(256,000)	121,000	499,000	219,000	(55,000)	(75,000)		(253,000)	(97,000)	583,000	(480,000)	(74,000)
Net Income Attributable to Graham Holdings Company	334,410,000	76,560,000	750,349,000	132,524,000	156,473,000	30,349,000		44,881,000	5,162,000	1,293,843,000	236,865,000	132,113,000
Redeemable Preferred Stock Dividends	0	(209,000)	(212,000)	(426,000)	0	(205,000)		(206,000)	(444,000)	(847,000)	(855,000)	(895,000)
Net Income Attributable to Graham Holdings Company Common Stockholders	334,410,000	76,351,000	750,137,000	132,098,000	156,473,000	30,144,000		44,675,000	4,718,000	1,292,996,000	236,010,000	131,218,000
Amounts Attributable to Graham Holdings Company Common Stockholders
Income from continuing operations	332,102,000	83,331,000	374,948,000	130,366,000	50,138,000	54,132,000		46,447,000	21,278,000	920,747,000	171,995,000	50,323,000
Income (Loss) from Discontinued Operations, Net of Tax	2,308,000	(6,980,000)	375,189,000	1,732,000	106,335,000	(23,988,000)		(1,772,000)	(16,560,000)	372,249,000	64,015,000	80,895,000
Net Income Attributable to Graham Holdings Company Common Stockholders	334,410,000	76,351,000	750,137,000	132,098,000	156,473,000	30,144,000		44,675,000	4,718,000	1,292,996,000	236,010,000	131,218,000
Per Share Information Attributable to Graham Holdings Company Common Stockholders
Basic income per common share from continuing operations in dollars per share	$ 57.31	$ 14.38	$ 50.39	$ 17.62	$ 6.79	$ 7.29		$ 6.26	$ 2.87	$ 139.44	$ 23.39	$ 6.40
Basic income per common share from discontinued operations in dollars per share	$ 0.40	$ (1.20)	$ 50.41	$ 0.23	$ 14.41	$ (3.22)		$ (0.24)	$ (2.23)	$ 56.37	$ 8.71	$ 10.99
Basic net income per common share in dollars per share	$ 57.71	$ 13.18	$ 100.80	$ 17.85	$ 21.20	$ 4.07		$ 6.02	$ 0.64	$ 195.81	$ 32.10	$ 17.39
Diluted income per common share from continuing operations in dollars per share	$ 57.01	$ 14.32	$ 50.22	$ 17.56	$ 6.77	$ 7.28		$ 6.26	$ 2.87	$ 138.88	$ 23.36	$ 6.40
Diluted income per common share from discontinued operations in dollars per share	$ 0.40	$ (1.20)	$ 50.26	$ 0.23	$ 14.37	$ (3.23)		$ (0.24)	$ (2.23)	$ 56.15	$ 8.69	$ 10.99
Diluted net income per common share in dollars per share	$ 57.41	$ 13.12	$ 100.48	$ 17.79	$ 21.14	$ 4.05		$ 6.02	$ 0.64	$ 195.03	$ 32.05	$ 17.39
Basic average number of common shares outstanding in shares	5,678	5,671	7,284	7,275	7,266	7,231		7,229	7,227	6,470	7,238	7,360
Diluted average number of common shares outstanding in shares	5,770	5,757	7,363	7,352	7,347	7,337		7,283	7,266	6,559	7,333	7,404
Quarterly comprehensive income	240,005,000	68,246,000	593,463,000	146,115,000	555,695,000	37,533,000		61,125,000	29,129,000	1,047,829,000	683,482,000	219,609,000
Immaterial revision amount						$ 29,900,000

[1] Other revenue and operating expenses of $29.9 million from the third quarter of 2013 have been revised to correctly present revenue on a net basis for certain third quarter contracts that were previously reported on a gross basis. The amounts did not impact net income, and the Company concluded that the amounts were not material to the Company’s consolidated financial statements.