Business Segments (Information by Operating Segment) (Details 1) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Segment Reporting Information [Line Items]
Operating Revenues	$ 1,012,438	$ 809,436	$ 2,860,461	$ 2,323,043
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	74,167	26,127	183,267	130,203
Amortization of Intangible Assets and Impairment of Long-Lived Assets	14,635	42,734	44,436	75,375
Income (Loss) from Operations	59,532	(16,607)	138,831	54,828
Equity in (losses) earnings of affiliates, net	(1,111)	12,964	2,920	28,168
Interest Expense, Net	(10,776)	(9,422)	(36,755)	(22,457)
Non-operating pension and postretirement benefit income, net	50,687	27,561	152,063	81,564
(Loss) gain on marketable equity securities, net	(54,250)	14,069	(172,878)	176,981
Other Income, Net	2,358	5,218	6,410	27,660
Income Before Income Taxes	46,440	33,783	90,591	346,744
Depreciation of property, plant and equipment	19,657	18,741	58,545	51,886
Pension Service Cost	5,557	5,775	16,581	17,254
Identifiable Assets	4,117,507		4,117,507		$ 4,153,570
Marketable equity securities	597,456		597,456		809,997
Investments in Affiliates	169,422		169,422		155,444
Prepaid Pension Cost	2,392,746		2,392,746		2,306,514
Total Assets	7,277,131		7,277,131		7,425,525
Amortization of Intangible Assets	14,635	15,981	44,436	43,807
Impairment of goodwill and other long-lived assets	0	26,753	0	31,568
Operating Segments [Member] | Education [Member]
Segment Reporting Information [Line Items]
Operating Revenues	355,064	335,999	1,066,089	1,005,300
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	22,625	13,869	69,952	57,238
Amortization of Intangible Assets and Impairment of Long-Lived Assets	3,980	3,955	12,190	15,240
Income (Loss) from Operations	18,645	9,914	57,762	41,998
Depreciation of property, plant and equipment	8,360	8,217	25,396	23,479
Pension Service Cost	2,233	2,339	6,700	7,020
Identifiable Assets	1,847,201		1,847,201		2,026,782
Amortization of Intangible Assets	3,980	3,888	12,190	11,967
Impairment of goodwill and other long-lived assets	0	67	0	3,273
Operating Segments [Member] | Education [Member] | Reportable Subsegments [Member] | Kaplan International [Member]
Segment Reporting Information [Line Items]
Operating Revenues	193,085	168,143	598,469	521,314
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	8,503	(999)	48,130	23,285
Income (Loss) from Operations	8,503	(999)	48,130	23,285
Depreciation of property, plant and equipment	5,709	5,516	17,258	15,603
Pension Service Cost	67	73	202	221
Identifiable Assets	1,336,856		1,336,856		1,493,868
Operating Segments [Member] | Education [Member] | Reportable Subsegments [Member] | Higher Education [Member]
Segment Reporting Information [Line Items]
Operating Revenues	80,684	85,518	229,467	239,944
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	9,027	9,525	16,768	18,152
Income (Loss) from Operations	9,027	9,525	16,768	18,152
Depreciation of property, plant and equipment	988	923	3,072	2,648
Pension Service Cost	961	1,109	2,862	3,329
Identifiable Assets	177,042		177,042		187,789
Operating Segments [Member] | Education [Member] | Reportable Subsegments [Member] | Supplemental Education [Member]
Segment Reporting Information [Line Items]
Operating Revenues	79,566	80,489	233,416	238,055
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	9,471	11,769	17,671	33,079
Income (Loss) from Operations	9,471	11,769	17,671	33,079
Depreciation of property, plant and equipment	1,570	1,658	4,787	4,904
Pension Service Cost	1,029	954	3,106	2,861
Identifiable Assets	267,826		267,826		286,877
Operating Segments [Member] | Education [Member] | Kaplan Corporate and Other [Member]
Segment Reporting Information [Line Items]
Operating Revenues	4,927	3,761	13,726	10,739
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	(4,579)	(6,426)	(12,783)	(17,375)
Income (Loss) from Operations	(8,559)	(10,381)	(24,973)	(32,615)
Depreciation of property, plant and equipment	93	120	279	324
Pension Service Cost	176	203	530	609
Identifiable Assets	65,477		65,477		58,248
Operating Segments [Member] | Education [Member] | Intersubsegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating Revenues	(3,198)	(1,912)	(8,989)	(4,752)
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	203	0	166	97
Income (Loss) from Operations	203	0	166	97
Operating Segments [Member] | Television Broadcasting [Member]
Segment Reporting Information [Line Items]
Operating Revenues	135,165	126,498	380,970	360,089
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	53,691	41,911	135,991	113,212
Amortization of Intangible Assets and Impairment of Long-Lived Assets	1,360	1,361	4,080	4,081
Income (Loss) from Operations	52,331	40,550	131,911	109,131
Depreciation of property, plant and equipment	2,961	3,462	9,335	10,478
Pension Service Cost	884	901	2,666	2,692
Identifiable Assets	422,465		422,465		448,627
Operating Segments [Member] | Manufacturing [Member]
Segment Reporting Information [Line Items]
Operating Revenues	122,964	99,766	365,966	356,849
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	14,723	(6,942)	39,527	27,990
Amortization of Intangible Assets and Impairment of Long-Lived Assets	5,076	32,541	15,403	46,138
Income (Loss) from Operations	9,647	(39,483)	24,124	(18,148)
Depreciation of property, plant and equipment	2,358	2,402	7,109	7,346
Pension Service Cost	276	321	828	962
Identifiable Assets	494,335		494,335		486,304
Operating Segments [Member] | Healthcare [Member]
Segment Reporting Information [Line Items]
Operating Revenues	87,176	55,445	230,816	160,184
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	6,953	6,016	21,491	23,312
Amortization of Intangible Assets and Impairment of Long-Lived Assets	905	756	2,822	2,317
Income (Loss) from Operations	6,048	5,260	18,669	20,995
Depreciation of property, plant and equipment	590	322	1,455	970
Pension Service Cost	138	141	417	421
Identifiable Assets	245,276		245,276		194,823
Operating Segments [Member] | Automotive [Member]
Segment Reporting Information [Line Items]
Operating Revenues	211,396	84,702	509,965	242,702
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	11,050	4,506	25,493	8,815
Amortization of Intangible Assets and Impairment of Long-Lived Assets	0	0	0	0
Income (Loss) from Operations	11,050	4,506	25,493	8,815
Depreciation of property, plant and equipment	1,067	535	2,596	1,555
Pension Service Cost	6	0	17	0
Identifiable Assets	411,440		411,440		238,200
Operating Segments [Member] | Other Businesses [Member]
Segment Reporting Information [Line Items]
Operating Revenues	101,207	107,539	308,150	199,477
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	(17,840)	(19,752)	(68,301)	(57,533)
Amortization of Intangible Assets and Impairment of Long-Lived Assets	3,314	4,121	9,941	7,599
Income (Loss) from Operations	(21,154)	(23,873)	(78,242)	(65,132)
Depreciation of property, plant and equipment	4,169	3,649	12,198	7,578
Pension Service Cost	552	458	1,549	1,314
Identifiable Assets	620,287		620,287		689,872
Corporate Office [Member]
Segment Reporting Information [Line Items]
Operating Revenues	0	0	0	0
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	(17,035)	(13,481)	(40,886)	(42,831)
Amortization of Intangible Assets and Impairment of Long-Lived Assets	0	0	0	0
Income (Loss) from Operations	(17,035)	(13,481)	(40,886)	(42,831)
Depreciation of property, plant and equipment	152	154	456	480
Pension Service Cost	1,468	1,615	4,404	4,845
Identifiable Assets	76,503		76,503		$ 68,962
Intersegment Elimination [Member]
Segment Reporting Information [Line Items]
Operating Revenues	$ (534)	$ (513)	$ (1,495)	$ (1,558)