Business Segments (Information by Operating Segment) (Details 2) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Segment Reporting Information [Line Items]
Operating Revenues	$ 914,721	$ 712,455
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Long-Lived Assets	54,883	48,828
Amortization of Intangible Assets and Impairment of Long-Lived Assets	14,912	14,984
Income (Loss) from Operations	39,971	33,844
Equity in earnings of affiliates, net	2,604	13,428
Interest Expense, Net	(10,702)	(7,558)
Non-operating pension and postretirement benefit income, net	50,505	28,787
Gain on marketable equity securities, net	46,912	79,214
Other Income, Net	2,876	6,320
Income Before Income Taxes	132,166	154,035
Depreciation of property, plant and equipment	19,475	16,545
Pension Service Cost	6,031	5,602
Identifiable Assets	4,051,601		$ 4,153,570
Marketable equity securities	801,178		809,997
Investments in Affiliates	172,584		155,444
Prepaid Pension Cost	2,334,773		2,306,514
Total Assets	7,360,136		7,425,525
Amortization of Intangible Assets	14,912	13,937
Impairment of long-lived assets	0	1,047
Operating Segments [Member] | Education [Member]
Segment Reporting Information [Line Items]
Operating Revenues	358,012	329,317
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Long-Lived Assets	24,558	24,148
Amortization of Intangible Assets and Impairment of Long-Lived Assets	4,146	5,212
Income (Loss) from Operations	20,412	18,936
Depreciation of property, plant and equipment	8,505	7,780
Pension Service Cost	2,536	2,283
Identifiable Assets	1,931,039		2,026,782
Amortization of Intangible Assets	4,146	4,165
Impairment of long-lived assets	0	1,047
Operating Segments [Member] | Education [Member] | Reportable Subsegments [Member] | Kaplan International [Member]
Segment Reporting Information [Line Items]
Operating Revenues	204,513	171,895
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Long-Lived Assets	20,564	10,207
Income (Loss) from Operations	20,564	10,207
Depreciation of property, plant and equipment	5,755	5,252
Pension Service Cost	72	71
Identifiable Assets	1,424,270		1,493,868
Operating Segments [Member] | Education [Member] | Reportable Subsegments [Member] | Higher Education [Member]
Segment Reporting Information [Line Items]
Operating Revenues	75,808	75,686
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Long-Lived Assets	5,037	6,253
Income (Loss) from Operations	5,037	6,253
Depreciation of property, plant and equipment	1,020	852
Pension Service Cost	1,081	1,083
Identifiable Assets	178,681		187,789
Operating Segments [Member] | Education [Member] | Reportable Subsegments [Member] | Supplemental Education [Member]
Segment Reporting Information [Line Items]
Operating Revenues	76,304	79,655
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Long-Lived Assets	3,371	12,497
Income (Loss) from Operations	3,371	12,497
Depreciation of property, plant and equipment	1,639	1,576
Pension Service Cost	1,182	931
Identifiable Assets	275,191		286,877
Operating Segments [Member] | Education [Member] | Kaplan Corporate and Other [Member]
Segment Reporting Information [Line Items]
Operating Revenues	4,345	3,363
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Long-Lived Assets	(4,433)	(4,907)
Income (Loss) from Operations	(8,579)	(10,119)
Depreciation of property, plant and equipment	91	100
Pension Service Cost	201	198
Identifiable Assets	52,897		58,248
Operating Segments [Member] | Education [Member] | Intersubsegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating Revenues	(2,958)	(1,282)
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Long-Lived Assets	19	98
Income (Loss) from Operations	19	98
Operating Segments [Member] | Television Broadcasting [Member]
Segment Reporting Information [Line Items]
Operating Revenues	123,419	113,625
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Long-Lived Assets	41,258	34,337
Amortization of Intangible Assets and Impairment of Long-Lived Assets	1,360	1,359
Income (Loss) from Operations	39,898	32,978
Depreciation of property, plant and equipment	3,289	3,473
Pension Service Cost	926	835
Identifiable Assets	442,468		448,627
Operating Segments [Member] | Manufacturing [Member]
Segment Reporting Information [Line Items]
Operating Revenues	115,940	115,960
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Long-Lived Assets	15,138	15,894
Amortization of Intangible Assets and Impairment of Long-Lived Assets	5,163	6,987
Income (Loss) from Operations	9,975	8,907
Depreciation of property, plant and equipment	2,428	2,517
Pension Service Cost	328	395
Identifiable Assets	495,452		486,304
Operating Segments [Member] | Healthcare [Member]
Segment Reporting Information [Line Items]
Operating Revenues	67,255	50,043
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Long-Lived Assets	7,288	7,921
Amortization of Intangible Assets and Impairment of Long-Lived Assets	929	781
Income (Loss) from Operations	6,359	7,140
Depreciation of property, plant and equipment	410	317
Pension Service Cost	186	172
Identifiable Assets	203,534		194,823
Operating Segments [Member] | Automotive [Member]
Segment Reporting Information [Line Items]
Operating Revenues	150,967	67,727
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Long-Lived Assets	7,078	524
Amortization of Intangible Assets and Impairment of Long-Lived Assets	0	0
Income (Loss) from Operations	7,078	524
Depreciation of property, plant and equipment	777	530
Pension Service Cost	6	0
Identifiable Assets	243,766		238,200
Operating Segments [Member] | Other Businesses [Member]
Segment Reporting Information [Line Items]
Operating Revenues	99,617	36,312
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Long-Lived Assets	(27,430)	(19,216)
Amortization of Intangible Assets and Impairment of Long-Lived Assets	3,314	645
Income (Loss) from Operations	(30,744)	(19,861)
Depreciation of property, plant and equipment	3,915	1,760
Pension Service Cost	520	369
Identifiable Assets	626,418		689,872
Corporate Office [Member]
Segment Reporting Information [Line Items]
Operating Revenues	0	0
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Long-Lived Assets	(13,007)	(14,780)
Amortization of Intangible Assets and Impairment of Long-Lived Assets	0	0
Income (Loss) from Operations	(13,007)	(14,780)
Depreciation of property, plant and equipment	151	168
Pension Service Cost	1,529	1,548
Identifiable Assets	108,924		$ 68,962
Intersegment Elimination [Member]
Segment Reporting Information [Line Items]
Operating Revenues	$ (489)	$ (529)