Business Segments (Information by Operating Segment) (Details 2) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Segment Reporting Information [Line Items]
Operating Revenues	$ 933,302	$ 801,152	$ 1,848,023	$ 1,513,607
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Long-Lived Assets	54,217	55,248	109,100	104,076
Amortization of Intangible Assets and Impairment of Long-Lived Assets	14,889	17,657	29,801	32,641
Income (Loss) from Operations	39,328	37,591	79,299	71,435
Equity in earnings of affiliates, net	1,427	1,776	4,031	15,204
Interest Expense, Net	(15,277)	(5,477)	(25,979)	(13,035)
Non-operating pension and postretirement benefit income, net	50,871	25,216	101,376	54,003
(Loss) gain on marketable equity securities, net	(165,540)	83,698	(118,628)	162,912
Other Income, Net	1,176	16,122	4,052	22,442
(Loss) Income Before Income Taxes	(88,015)	158,926	44,151	312,961
Depreciation of property, plant and equipment	19,413	16,600	38,888	33,145
Pension Service Cost	4,993	5,877	11,024	11,479
Identifiable Assets	3,975,954		3,975,954		$ 4,153,570
Marketable equity securities	648,604		648,604		809,997
Investments in Affiliates	172,612		172,612		155,444
Prepaid Pension Cost	2,364,135		2,364,135		2,306,514
Total Assets	7,161,305		7,161,305		7,425,525
Amortization of Intangible Assets	14,889	13,889	29,801	27,826
Impairment of long-lived assets	0	3,768	0	4,815
Operating Segments [Member] | Education [Member]
Segment Reporting Information [Line Items]
Operating Revenues	353,013	339,984	711,025	669,301
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Long-Lived Assets	22,769	19,221	47,327	43,369
Amortization of Intangible Assets and Impairment of Long-Lived Assets	4,064	6,073	8,210	11,285
Income (Loss) from Operations	18,705	13,148	39,117	32,084
Depreciation of property, plant and equipment	8,531	7,482	17,036	15,262
Pension Service Cost	1,931	2,398	4,467	4,681
Identifiable Assets	1,824,482		1,824,482		2,026,782
Amortization of Intangible Assets	4,064	3,914	8,210	8,079
Impairment of long-lived assets	0	2,159	0	3,206
Operating Segments [Member] | Education [Member] | Reportable Subsegments [Member] | Kaplan International [Member]
Segment Reporting Information [Line Items]
Operating Revenues	200,871	181,276	405,384	353,171
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Long-Lived Assets	19,063	14,077	39,627	24,284
Income (Loss) from Operations	19,063	14,077	39,627	24,284
Depreciation of property, plant and equipment	5,794	4,835	11,549	10,087
Pension Service Cost	63	77	135	148
Identifiable Assets	1,320,183		1,320,183		1,493,868
Operating Segments [Member] | Education [Member] | Reportable Subsegments [Member] | Higher Education [Member]
Segment Reporting Information [Line Items]
Operating Revenues	72,975	78,740	148,783	154,426
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Long-Lived Assets	2,704	2,374	7,741	8,627
Income (Loss) from Operations	2,704	2,374	7,741	8,627
Depreciation of property, plant and equipment	1,064	873	2,084	1,725
Pension Service Cost	820	1,137	1,901	2,220
Identifiable Assets	177,954		177,954		187,789
Operating Segments [Member] | Education [Member] | Reportable Subsegments [Member] | Supplemental Education [Member]
Segment Reporting Information [Line Items]
Operating Revenues	77,546	77,911	153,850	157,566
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Long-Lived Assets	4,829	8,813	8,200	21,310
Income (Loss) from Operations	4,829	8,813	8,200	21,310
Depreciation of property, plant and equipment	1,578	1,670	3,217	3,246
Pension Service Cost	895	976	2,077	1,907
Identifiable Assets	268,054		268,054		286,877
Operating Segments [Member] | Education [Member] | Kaplan Corporate and Other [Member]
Segment Reporting Information [Line Items]
Operating Revenues	4,454	3,615	8,799	6,978
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Long-Lived Assets	(3,771)	(6,042)	(8,204)	(10,949)
Income (Loss) from Operations	(7,835)	(12,115)	(16,414)	(22,234)
Depreciation of property, plant and equipment	95	104	186	204
Pension Service Cost	153	208	354	406
Identifiable Assets	58,291		58,291		58,248
Operating Segments [Member] | Education [Member] | Intersubsegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating Revenues	(2,833)	(1,558)	(5,791)	(2,840)
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Long-Lived Assets	(56)	(1)	(37)	97
Income (Loss) from Operations	(56)	(1)	(37)	97
Operating Segments [Member] | Television Broadcasting [Member]
Segment Reporting Information [Line Items]
Operating Revenues	122,386	119,966	245,805	233,591
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Long-Lived Assets	41,042	36,964	82,300	71,301
Amortization of Intangible Assets and Impairment of Long-Lived Assets	1,360	1,361	2,720	2,720
Income (Loss) from Operations	39,682	35,603	79,580	68,581
Depreciation of property, plant and equipment	3,085	3,543	6,374	7,016
Pension Service Cost	856	956	1,782	1,791
Identifiable Assets	429,070		429,070		448,627
Operating Segments [Member] | Manufacturing [Member]
Segment Reporting Information [Line Items]
Operating Revenues	127,062	141,123	243,002	257,083
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Long-Lived Assets	9,666	19,038	24,804	34,932
Amortization of Intangible Assets and Impairment of Long-Lived Assets	5,164	6,610	10,327	13,597
Income (Loss) from Operations	4,502	12,428	14,477	21,335
Depreciation of property, plant and equipment	2,323	2,427	4,751	4,944
Pension Service Cost	224	246	552	641
Identifiable Assets	500,918		500,918		486,304
Operating Segments [Member] | Healthcare [Member]
Segment Reporting Information [Line Items]
Operating Revenues	76,385	54,696	143,640	104,739
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Long-Lived Assets	7,250	9,375	14,538	17,296
Amortization of Intangible Assets and Impairment of Long-Lived Assets	988	780	1,917	1,561
Income (Loss) from Operations	6,262	8,595	12,621	15,735
Depreciation of property, plant and equipment	455	331	865	648
Pension Service Cost	93	108	279	280
Identifiable Assets	217,190		217,190		194,823
Operating Segments [Member] | Automotive [Member]
Segment Reporting Information [Line Items]
Operating Revenues	147,602	90,273	298,569	158,000
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Long-Lived Assets	7,365	3,785	14,443	4,309
Amortization of Intangible Assets and Impairment of Long-Lived Assets	0	0	0	0
Income (Loss) from Operations	7,365	3,785	14,443	4,309
Depreciation of property, plant and equipment	752	490	1,529	1,020
Pension Service Cost	5	0	11	0
Identifiable Assets	268,156		268,156		238,200
Operating Segments [Member] | Other Businesses [Member]
Segment Reporting Information [Line Items]
Operating Revenues	107,326	55,626	206,943	91,938
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Long-Lived Assets	(23,031)	(18,565)	(50,461)	(37,781)
Amortization of Intangible Assets and Impairment of Long-Lived Assets	3,313	2,833	6,627	3,478
Income (Loss) from Operations	(26,344)	(21,398)	(57,088)	(41,259)
Depreciation of property, plant and equipment	4,114	2,169	8,029	3,929
Pension Service Cost	477	487	997	856
Identifiable Assets	623,159		623,159		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 Long-Lived Assets	(10,844)	(14,570)	(23,851)	(29,350)
Amortization of Intangible Assets and Impairment of Long-Lived Assets	0	0	0	0
Income (Loss) from Operations	(10,844)	(14,570)	(23,851)	(29,350)
Depreciation of property, plant and equipment	153	158	304	326
Pension Service Cost	1,407	1,682	2,936	3,230
Identifiable Assets	112,979		112,979		$ 68,962
Intersegment Elimination [Member]
Segment Reporting Information [Line Items]
Operating Revenues	$ (472)	$ (516)	$ (961)	$ (1,045)