Business Segments (Information by Operating Segment) (Details 1) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Segment Reporting Information [Line Items]
Operating Revenues	$ 676,087	$ 628,933	$ 1,258,804	$ 1,230,673
Income (Loss) from Operations	68,361	74,140	97,415	126,012
Equity in earnings (losses) of affiliates, net	1,331	(891)	1,980	113
Interest Expense, Net	(7,862)	(7,250)	(14,628)	(14,607)
Other income, net	4,069	19,000	4,918	34,096
Income Before Income Taxes	65,899	84,999	89,685	145,614
Depreciation of property, plant and equipment	15,871	16,045	30,523	32,806
Amortization of Intangible Assets	10,531	6,278	17,367	12,540
Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	19,755	6,278	26,591	12,540
Net Pension (Credit) Expense	(14,829)	(12,266)	(29,517)	(24,325)
Identifiable Assets	3,142,602		3,142,602		$ 3,068,042
Investments in Marketable Equity Securities	447,763		447,763		424,229
Investments in Affiliates	67,812		67,812		58,806
Prepaid Pension Cost	850,262		850,262		881,593
Total Assets	4,508,439		4,508,439		4,432,670
Operating Segments [Member] | Education [Member]
Segment Reporting Information [Line Items]
Operating Revenues	386,499	419,213	759,396	820,289
Income (Loss) from Operations	32,925	32,892	41,956	47,380
Depreciation of property, plant and equipment	8,325	10,242	16,909	21,345
Amortization of Intangible Assets	1,323	1,704	2,443	3,385
Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	1,323	1,704	2,443	3,385
Net Pension (Credit) Expense	2,153	3,018	4,859	6,127
Identifiable Assets	1,494,736		1,494,736		1,479,267
Operating Segments [Member] | Education [Member] | Kaplan Corporate and Other [Member]
Segment Reporting Information [Line Items]
Operating Revenues	57	18	71	143
Income (Loss) from Operations	(6,451)	(7,811)	(14,920)	(17,216)
Depreciation of property, plant and equipment	135	315	265	402
Net Pension (Credit) Expense	(889)	278	(1,225)	647
Identifiable Assets	21,007		21,007		21,509
Operating Segments [Member] | Education [Member] | Reportable Subsegments [Member] | Higher Education [Member]
Segment Reporting Information [Line Items]
Operating Revenues	139,204	157,980	283,514	323,529
Income (Loss) from Operations	17,711	17,237	30,315	38,543
Depreciation of property, plant and equipment	3,249	3,993	6,680	8,168
Net Pension (Credit) Expense	2,044	1,905	4,088	3,810
Identifiable Assets	339,304		339,304		373,127
Operating Segments [Member] | Education [Member] | Reportable Subsegments [Member] | Test Preparation [Member]
Segment Reporting Information [Line Items]
Operating Revenues	75,730	79,349	140,298	145,811
Income (Loss) from Operations	5,741	7,036	2,877	4,726
Depreciation of property, plant and equipment	1,332	1,615	2,673	3,396
Net Pension (Credit) Expense	911	768	1,822	1,536
Identifiable Assets	133,482		133,482		133,709
Operating Segments [Member] | Education [Member] | Reportable Subsegments [Member] | Kaplan International [Member]
Segment Reporting Information [Line Items]
Operating Revenues	171,747	182,325	336,309	351,612
Income (Loss) from Operations	15,954	16,479	23,661	21,376
Depreciation of property, plant and equipment	3,609	4,319	7,291	9,379
Net Pension (Credit) Expense	87	67	174	134
Identifiable Assets	1,000,943		1,000,943		950,922
Operating Segments [Member] | Education [Member] | Intersubsegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating Revenues	(239)	(459)	(796)	(806)
Income (Loss) from Operations	(30)	(49)	23	(49)
Operating Segments [Member] | Television Broadcasting [Member]
Segment Reporting Information [Line Items]
Operating Revenues	106,102	96,520	197,598	188,538
Income (Loss) from Operations	39,264	44,215	65,233	85,435
Depreciation of property, plant and equipment	2,991	2,450	5,585	4,827
Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	970	63	1,872	126
Net Pension (Credit) Expense	479	418	972	857
Identifiable Assets	451,296		451,296		336,631
Operating Segments [Member] | Other Businesses [Member]
Segment Reporting Information [Line Items]
Operating Revenues	183,486	113,269	301,810	221,985
Income (Loss) from Operations	(8,918)	(5,062)	(19,482)	(10,792)
Depreciation of property, plant and equipment	4,264	3,073	7,448	6,100
Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	17,462	4,511	22,276	9,029
Net Pension (Credit) Expense	415	306	898	560
Identifiable Assets	946,499		946,499		796,935
Corporate Office [Member]
Segment Reporting Information [Line Items]
Operating Revenues	0	0	0	0
Income (Loss) from Operations	5,090	2,095	9,708	3,989
Depreciation of property, plant and equipment	291	280	581	534
Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	0	0	0	0
Net Pension (Credit) Expense	(17,876)	(16,008)	(36,246)	(31,869)
Identifiable Assets	250,071		250,071		$ 455,209
Intersegment Elimination [Member]
Segment Reporting Information [Line Items]
Operating Revenues	$ 0	$ (69)	$ 0	$ (139)