Business Segments (Information by Operating Segment) (Details 1) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Segment Reporting Information [Line Items]
Operating Revenues	$ 732,257	$ 692,199
Income (Loss) from Operations	8,085	40,003
Equity in (losses) earnings of affiliates, net	(1,547)	1,679
Interest Expense, Net	(6,527)	(5,725)
Non-operating pension and postretirement benefit income, net	18,403	19,928
(Loss) gain on marketable equity securities, net	(100,393)	24,066
Other income, net	2,688	29,351
(Loss) Income Before Income Taxes	(79,291)	109,302
Depreciation of property, plant and equipment	16,704	13,523
Amortization of Intangible Assets and Impairment of Goodwill and Intangible Assets	30,566	13,060
Amortization of Intangible Assets	14,165	13,060
Identifiable Assets	3,735,150		$ 3,891,557
Marketable equity securities	436,204		585,080
Investments in Affiliates	167,628		162,249
Prepaid Pension Cost	1,306,843		1,292,350
Total Assets	5,645,825		5,931,236
Defined Benefit Pension Plan [Member]
Segment Reporting Information [Line Items]
Pension Service Cost	5,783	5,221
Operating Segments [Member] | Education [Member]
Segment Reporting Information [Line Items]
Operating Revenues	356,378	372,454
Income (Loss) from Operations	4,692	25,595
Depreciation of property, plant and equipment	7,329	6,201
Amortization of Intangible Assets and Impairment of Goodwill and Intangible Assets	4,201	3,567
Amortization of Intangible Assets	4,201	3,567
Identifiable Assets	1,893,250		2,032,425
Operating Segments [Member] | Education [Member] | Defined Benefit Pension Plan [Member]
Segment Reporting Information [Line Items]
Pension Service Cost	2,585	2,664
Operating Segments [Member] | Education [Member] | Kaplan Corporate and Other [Member]
Segment Reporting Information [Line Items]
Operating Revenues	3,205	2,302
Income (Loss) from Operations	(5,723)	(11,404)
Depreciation of property, plant and equipment	89	52
Identifiable Assets	64,498		68,088
Operating Segments [Member] | Education [Member] | Kaplan Corporate and Other [Member] | Defined Benefit Pension Plan [Member]
Segment Reporting Information [Line Items]
Pension Service Cost	318	170
Operating Segments [Member] | Education [Member] | Reportable Subsegments [Member] | Kaplan International [Member]
Segment Reporting Information [Line Items]
Operating Revenues	199,615	185,756
Income (Loss) from Operations	18,980	24,285
Depreciation of property, plant and equipment	4,578	3,882
Identifiable Assets	1,316,435		1,455,122
Operating Segments [Member] | Education [Member] | Reportable Subsegments [Member] | Kaplan International [Member] | Defined Benefit Pension Plan [Member]
Segment Reporting Information [Line Items]
Pension Service Cost	112	117
Operating Segments [Member] | Education [Member] | Reportable Subsegments [Member] | Higher Education [Member]
Segment Reporting Information [Line Items]
Operating Revenues	73,537	82,780
Income (Loss) from Operations	(2,020)	1,915
Depreciation of property, plant and equipment	723	597
Identifiable Assets	206,661		196,761
Operating Segments [Member] | Education [Member] | Reportable Subsegments [Member] | Higher Education [Member] | Defined Benefit Pension Plan [Member]
Segment Reporting Information [Line Items]
Pension Service Cost	1,070	1,163
Operating Segments [Member] | Education [Member] | Reportable Subsegments [Member] | Test Preparation [Member]
Segment Reporting Information [Line Items]
Operating Revenues	42,839	61,150
Income (Loss) from Operations	(12,676)	(454)
Depreciation of property, plant and equipment	826	805
Identifiable Assets	151,541		151,655
Operating Segments [Member] | Education [Member] | Reportable Subsegments [Member] | Test Preparation [Member] | Defined Benefit Pension Plan [Member]
Segment Reporting Information [Line Items]
Pension Service Cost	823	866
Operating Segments [Member] | Education [Member] | Reportable Subsegments [Member] | Professional (U.S.) [Member]
Segment Reporting Information [Line Items]
Operating Revenues	38,449	41,214
Income (Loss) from Operations	6,126	11,259
Depreciation of property, plant and equipment	1,113	865
Identifiable Assets	154,115		160,799
Operating Segments [Member] | Education [Member] | Reportable Subsegments [Member] | Professional (U.S.) [Member] | Defined Benefit Pension Plan [Member]
Segment Reporting Information [Line Items]
Pension Service Cost	262	348
Operating Segments [Member] | Education [Member] | Intersubsegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating Revenues	(1,267)	(748)
Income (Loss) from Operations	5	(6)
Operating Segments [Member] | Television Broadcasting [Member]
Segment Reporting Information [Line Items]
Operating Revenues	115,448	108,223
Income (Loss) from Operations	35,776	35,540
Depreciation of property, plant and equipment	3,343	3,239
Amortization of Intangible Assets and Impairment of Goodwill and Intangible Assets	1,360	1,408
Identifiable Assets	457,048		463,689
Operating Segments [Member] | Television Broadcasting [Member] | Defined Benefit Pension Plan [Member]
Segment Reporting Information [Line Items]
Pension Service Cost	796	731
Operating Segments [Member] | Manufacturing [Member]
Segment Reporting Information [Line Items]
Operating Revenues	113,458	115,157
Income (Loss) from Operations	6,501	3,274
Depreciation of property, plant and equipment	2,527	2,433
Amortization of Intangible Assets and Impairment of Goodwill and Intangible Assets	7,137	6,530
Identifiable Assets	568,265		564,251
Operating Segments [Member] | Manufacturing [Member] | Defined Benefit Pension Plan [Member]
Segment Reporting Information [Line Items]
Pension Service Cost	394	25
Operating Segments [Member] | Healthcare [Member]
Segment Reporting Information [Line Items]
Operating Revenues	45,994	37,728
Income (Loss) from Operations	3,169	2,329
Depreciation of property, plant and equipment	540	610
Amortization of Intangible Assets and Impairment of Goodwill and Intangible Assets	1,310	1,398
Identifiable Assets	161,511		160,033
Operating Segments [Member] | Healthcare [Member] | Defined Benefit Pension Plan [Member]
Segment Reporting Information [Line Items]
Pension Service Cost	159	183
Operating Segments [Member] | SocialCode [Member]
Segment Reporting Information [Line Items]
Operating Revenues	12,023	13,447
Income (Loss) from Operations	(3,789)	(4,018)
Depreciation of property, plant and equipment	121	152
Amortization of Intangible Assets and Impairment of Goodwill and Intangible Assets	157	157
Identifiable Assets	134,650		221,746
Operating Segments [Member] | SocialCode [Member] | Defined Benefit Pension Plan [Member]
Segment Reporting Information [Line Items]
Pension Service Cost	237	248
Operating Segments [Member] | Other Businesses [Member]
Segment Reporting Information [Line Items]
Operating Revenues	89,268	45,230
Income (Loss) from Operations	(29,692)	(8,493)
Depreciation of property, plant and equipment	2,669	648
Amortization of Intangible Assets and Impairment of Goodwill and Intangible Assets	16,401	0
Identifiable Assets	317,940		345,649
Operating Segments [Member] | Other Businesses [Member] | Defined Benefit Pension Plan [Member]
Segment Reporting Information [Line Items]
Pension Service Cost	226	201
Corporate Office [Member]
Segment Reporting Information [Line Items]
Operating Revenues	0	0
Income (Loss) from Operations	(8,572)	(14,224)
Depreciation of property, plant and equipment	175	240
Amortization of Intangible Assets and Impairment of Goodwill and Intangible Assets	0	0
Identifiable Assets	202,486		$ 103,764
Corporate Office [Member] | Defined Benefit Pension Plan [Member]
Segment Reporting Information [Line Items]
Pension Service Cost	1,386	1,169
Intersegment Elimination [Member]
Segment Reporting Information [Line Items]
Operating Revenues	$ (312)	$ (40)