Business Segments (Information by Operating Segment) (Details 1) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Segment Reporting Information [Line Items]
Operating Revenues	$ 582,717	$ 601,740
Income (Loss) from Operations	29,054	51,872
Equity in earnings of affiliates, net	649	1,004
Interest Expense, Net	(6,766)	(7,357)
Other income, net	849	15,096
Income Before Income Taxes	23,786	60,615
Depreciation of property, plant and equipment	14,652	16,761
Amortization of intangible assets	6,836	6,262
Net Pension (Credit) Expense	(14,688)	(12,059)
Identifiable Assets	3,085,601		$ 3,068,042
Investments in Marketable Equity Securities	433,787		424,229
Investments in Affiliates	60,287		58,806
Prepaid Pension Cost	836,430		881,593
Total Assets	4,416,105		4,432,670
Operating Segments [Member] | Education [Member]
Segment Reporting Information [Line Items]
Operating Revenues	372,897	401,076
Income (Loss) from Operations	9,031	14,488
Depreciation of property, plant and equipment	8,584	11,103
Amortization of intangible assets	1,120	1,681
Net Pension (Credit) Expense	2,706	3,109
Identifiable Assets	1,475,285		1,479,267
Operating Segments [Member] | Education [Member] | Kaplan Corporate and Other [Member]
Segment Reporting Information [Line Items]
Operating Revenues	14	125
Income (Loss) from Operations	(8,469)
Depreciation of property, plant and equipment	130	87
Net Pension (Credit) Expense	(336)	369
Identifiable Assets	20,219		21,509
Operating Segments [Member] | Education [Member] | Reportable Subsegments [Member] | Higher Education [Member]
Segment Reporting Information [Line Items]
Operating Revenues	144,310	165,549
Income (Loss) from Operations	12,604	21,306
Depreciation of property, plant and equipment	3,431	4,175
Net Pension (Credit) Expense	2,044	1,905
Identifiable Assets	321,573		373,127
Operating Segments [Member] | Education [Member] | Reportable Subsegments [Member] | Test Preparation [Member]
Segment Reporting Information [Line Items]
Operating Revenues	64,568	66,462
Income (Loss) from Operations	(2,864)	(2,310)
Depreciation of property, plant and equipment	1,341	1,781
Net Pension (Credit) Expense	911	768
Identifiable Assets	133,061		133,709
Operating Segments [Member] | Education [Member] | Reportable Subsegments [Member] | Kaplan International [Member]
Segment Reporting Information [Line Items]
Operating Revenues	164,562	169,287
Income (Loss) from Operations	7,707	4,897
Depreciation of property, plant and equipment	3,682	5,060
Net Pension (Credit) Expense	87	67
Identifiable Assets	1,000,432		950,922
Operating Segments [Member] | Education [Member] | Reportable Subsegments [Member] | Kaplan Corporate and Other [Member]
Segment Reporting Information [Line Items]
Income (Loss) from Operations		(9,405)
Operating Segments [Member] | Education [Member] | Intersubsegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating Revenues	(557)	(347)
Income (Loss) from Operations	53	0
Operating Segments [Member] | Television Broadcasting [Member]
Segment Reporting Information [Line Items]
Operating Revenues	91,496	92,018
Income (Loss) from Operations	25,969	41,220
Depreciation of property, plant and equipment	2,594	2,377
Amortization of intangible assets	902	63
Net Pension (Credit) Expense	493	439
Identifiable Assets	445,278		336,631
Operating Segments [Member] | Other Businesses [Member]
Segment Reporting Information [Line Items]
Operating Revenues	118,324	108,716
Income (Loss) from Operations	(10,564)	(5,730)
Depreciation of property, plant and equipment	3,184	3,027
Amortization of intangible assets	4,814	4,518
Net Pension (Credit) Expense	483	254
Identifiable Assets	698,908		796,935
Corporate Office [Member]
Segment Reporting Information [Line Items]
Operating Revenues	0	0
Income (Loss) from Operations	4,618	1,894
Depreciation of property, plant and equipment	290	254
Amortization of intangible assets	0	0
Net Pension (Credit) Expense	(18,370)	(15,861)
Identifiable Assets	466,130		$ 455,209
Intersegment Elimination [Member]
Segment Reporting Information [Line Items]
Operating Revenues	$ 0	$ (70)