Business Segments (Information by Operating Segment) (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended							9 Months Ended		12 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2011
Operating Revenues	$ 902,479	$ 889,596	$ 836,840	$ 895,891	$ 877,637	$ 854,430	$ 827,612	$ 2,628,915	$ 2,559,679	$ 3,455,570	$ 3,525,997
Income (Loss) from Operations	81,873	104,770	53,398	(22,925)	93,236	71,208	37,661	240,041	202,105	179,180	334,118
Equity in Earnings of Affiliates, Net	5,892	3,868	3,418	2,785	4,099	3,314	3,888	13,178	11,301	14,086	5,949
Interest Expense, Net	(8,579)	(8,526)	(8,450)	(8,163)	(8,090)	(8,204)	(8,094)	(25,555)	(24,388)	(32,551)	(29,079)
Other (Expense) Income, Net	8,110	(12,858)	(4,083)	(17,572)	4,163	(635)	8,588	(8,831)	12,116	(5,456)	(55,200)
Income (Loss) From Continuing Operations Before Income Taxes	87,296	87,254	44,283	(45,875)	93,408	65,683	42,043	218,833	201,134	155,259	255,788
Depreciation of property, plant and equipment	55,633	57,816	59,895	73,731	57,588	56,594	56,165	173,344	170,347	244,078	223,403
Amortization of intangible assets and impairment of goodwill and other long-lived assets				119,203	5,090	4,407	3,839	9,867	13,336	132,539	22,201
Amortization of intangible assets	2,837	3,313	3,717	7,610	5,090	4,407	3,839	9,867	13,336	20,946	22,201
Impairment of goodwill and other long-lived assets				111,593		0	0			111,593	0
Net Pension (Credit) Expense	(2,733)	(2,638)	(2,729)	(631)	(1,134)	(3,368)	(3,475)	(8,100)	(7,977)	(8,608)	(23,219)
Identifiable Assets	3,820,650			4,104,624				3,820,650		4,104,624
Investment in Marketable Equity Securities	457,969			380,087				457,969		380,087
Investments In Affiliates	32,997			15,535				32,997		15,535
Prepaid Pension Cost	529,165			604,823				529,165		604,823
Assets of discontinued operations	255,100			0				255,100		0
Total Assets	5,095,881			5,105,069				5,095,881		5,105,069
Education [Member]
Operating Revenues	546,452	548,230	527,815	546,341	551,696	551,774	546,685	1,622,497	1,650,155	2,196,496	2,404,459
Income (Loss) from Operations	17,035	23,726	(4,056)	(111,874)	14,693	3,728	(11,915)	36,705	6,506	(105,368)	96,286
Depreciation of property, plant and equipment	18,978	20,064	22,588	37,431	22,024	21,011	20,717	61,630	63,752	101,183	83,735
Amortization of intangible assets and impairment of goodwill and other long-lived assets				117,784	4,489	3,803	3,236	7,168	11,528	129,312	19,417
Amortization of intangible assets	2,287	2,363	2,518
Net Pension (Credit) Expense	4,169	4,231	4,106	3,701	3,522	1,969	2,392	12,506	7,883	11,584	6,345
Identifiable Assets	1,739,301			1,988,015				1,739,301		1,988,015
Higher Education [Member]
Operating Revenues	266,061				273,703			811,013	872,948
Income (Loss) from Operations	14,719				1,510			42,354	16,329
Depreciation of property, plant and equipment	9,739				12,168			33,919	35,598
Net Pension (Credit) Expense	3,201				2,234			8,815	5,408
Identifiable Assets	643,342			949,260				643,342		949,260
Test Preparation [Member]
Operating Revenues	77,431				81,151			232,064	223,767
Income (Loss) from Operations	3,820				3,446			7,306	(4,067)
Depreciation of property, plant and equipment	5,034				5,544			14,658	14,308
Net Pension (Credit) Expense	731				554			2,012	1,381
Identifiable Assets	182,450			197,672				182,450		197,672
Kaplan International [Member]
Operating Revenues	201,305				194,158			574,086	546,862
Income (Loss) from Operations	12,020				20,365			24,907	34,293
Depreciation of property, plant and equipment	3,903				3,841			12,015	12,490
Net Pension (Credit) Expense	99				112			273	113
Identifiable Assets	878,123			818,613				878,123		818,613
Kaplan Corporate and Other [Member]
Operating Revenues	2,223				3,809			6,496	10,283
Income (Loss) from Operations	(13,680)				(10,852)			(38,243)	(40,628)
Depreciation of property, plant and equipment	302				471			1,038	1,356
Net Pension (Credit) Expense	138				622			1,406	981
Identifiable Assets	35,386			22,470				35,386		22,470
Cable Television [Member]
Operating Revenues	202,381	204,550	200,138	201,703	199,625	195,579	190,210	607,069	585,414	787,117	760,221
Income (Loss) from Operations	39,715	44,710	36,613	43,445	39,913	38,446	32,777	121,038	111,136	154,581	156,844
Depreciation of property, plant and equipment	32,946	33,964	33,733	32,366	32,310	32,234	32,197	100,643	96,741	129,107	126,302
Amortization of intangible assets and impairment of goodwill and other long-lived assets				52	52	53	54	168	159	211	267
Amortization of intangible assets	61	57	50
Net Pension (Credit) Expense	973	913	882	802	694	514	530	2,768	1,738	2,540	1,924
Identifiable Assets	1,189,084			1,187,603				1,189,084		1,187,603
Television Broadcasting [Member]
Operating Revenues	87,063	99,320	85,270	116,192	106,411	95,591	81,497	271,653	283,499	399,691	319,206
Income (Loss) from Operations	36,304	47,704	35,362	62,833	54,082	43,728	30,999	119,370	128,809	191,642	117,089
Depreciation of property, plant and equipment	3,109	3,151	3,145	3,545	3,126	3,222	3,125	9,405	9,473	13,018	12,448
Amortization of intangible assets and impairment of goodwill and other long-lived assets				0	0	0	0	0	0	0	0
Amortization of intangible assets	0	0	0
Net Pension (Credit) Expense	1,251	1,213	1,288	1,523	1,432	1,055	960	3,752	3,447	4,970	1,669
Identifiable Assets	371,726			374,075				371,726		374,075
Other Businesses [Member]
Operating Revenues	66,632	37,572	23,814	31,655	20,187	11,666	9,329	128,018	41,182	72,837	42,891
Income (Loss) from Operations	(5,046)	(5,968)	(8,542)	(9,935)	(7,324)	(9,005)	(6,746)	(19,556)	(23,075)	(33,010)	(16,771)
Depreciation of property, plant and equipment	555	577	429	389	128	127	126	1,561	381	770	674
Amortization of intangible assets and impairment of goodwill and other long-lived assets				1,367	549	551	549	2,531	1,649	3,016	2,517
Amortization of intangible assets	489	893	1,149
Net Pension (Credit) Expense	173	134	116	55	45	33	36	423	114	169	132
Identifiable Assets	137,068			88,393				137,068		88,393
Corporate Office [Member]
Operating Revenues	0	0	0	0	0	0	0	0	0	0	0
Income (Loss) from Operations	(6,135)	(5,402)	(5,979)	(7,394)	(8,128)	(5,689)	(7,454)	(17,516)	(21,271)	(28,665)	(19,330)
Depreciation of property, plant and equipment	45	60	0	0	0	0	0	105	0	0	244
Amortization of intangible assets and impairment of goodwill and other long-lived assets				0	0	0	0	0	0	0	0
Amortization of intangible assets	0	0	0
Net Pension (Credit) Expense	(9,299)	(9,129)	(9,121)	(6,712)	(6,827)	(6,939)	(7,393)	(27,549)	(21,159)	(27,871)	(33,289)
Identifiable Assets	383,471			466,538				383,471		466,538
Intersegment Elimination [Member]
Operating Revenues	(49)	(76)	(197)	0	(282)	(180)	(109)	(322)	(571)	(571)	(780)
Intersegment Elimination [Member] | Education [Member]
Operating Revenues	(568)				(1,125)			(1,162)	(3,705)
Income (Loss) from Operations	$ 156				$ 224			$ 381	$ 579