Business Segments (Information by Operating Segment) (Details 1) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Segment Reporting Information [Line Items]
Operating Revenues	$ 1,207,162	$ 1,111,519	$ 3,545,104	$ 3,248,064
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	90,033	52,968	198,482	166,672
Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	8,385	110,080	55,481	138,073
Income (Loss) from Operations	81,648	(57,112)	143,001	28,599
Equity in losses of affiliates, net	(13,361)	(791)	(8,470)	(2,245)
Interest Expense, Net	(23,619)	(9,824)	(130,041)	(33,140)
Non-operating pension and postretirement benefit income, net	38,307	35,653	105,379	97,313
Gain on marketable equity securities, net	30,496	16,759	154,276	113,429
Other (Expense) Income, Net	(465)	3,581	2,973	22,458
Income (Loss) Before Income Taxes	113,006	(11,734)	267,118	226,414
Depreciation of property, plant and equipment	21,332	22,207	66,032	63,335
Pension Service Cost	14,761	8,490	42,866	25,306
Capital Expenditures	23,771	26,742	66,008	71,581
Identifiable Assets	4,286,203		4,286,203		$ 4,197,459
Marketable equity securities	825,416		825,416		690,153
Investments in Affiliates	168,161		168,161		186,480
Prepaid Pension Cost	2,141,036		2,141,036		2,113,638
Total Assets	7,420,816		7,420,816		7,187,730
Amortization of Intangible Assets	8,385	11,759	29,194	39,007
Impairment of goodwill and other long-lived assets	0	98,321	26,287	99,066
Operating Segments [Member] | Education [Member]
Segment Reporting Information [Line Items]
Operating Revenues	438,090	411,837	1,283,587	1,192,105
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	37,311	33,069	109,021	94,625
Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	2,421	3,210	8,267	11,610
Income (Loss) from Operations	34,890	29,859	100,754	83,015
Depreciation of property, plant and equipment	8,576	10,000	26,736	28,428
Pension Service Cost	4,445	2,226	13,267	6,680
Capital Expenditures	5,811	8,316	18,468	23,516
Identifiable Assets	2,037,877		2,037,877		2,021,471
Amortization of Intangible Assets	2,421	3,210	8,267	11,133
Impairment of goodwill and other long-lived assets	0	0	0	477
Operating Segments [Member] | Education [Member] | Kaplan Corporate and Other [Member]
Segment Reporting Information [Line Items]
Operating Revenues	158	3,101	5,739	8,360
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	(10,717)	(7,412)	(26,357)	(20,074)
Income (Loss) from Operations	(13,138)	(10,622)	(34,624)	(31,684)
Depreciation of property, plant and equipment	8	26	57	78
Pension Service Cost	382	122	1,137	523
Capital Expenditures	0	0	0	22
Identifiable Assets	47,829		47,829		45,991
Operating Segments [Member] | Education [Member] | Intersubsegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating Revenues	(866)	(1,497)	(4,192)	(8,062)
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	(81)	67	8	92
Income (Loss) from Operations	(81)	67	8	92
Operating Segments [Member] | Education [Member] | Kaplan International [Member] | Reportable Subsegments [Member]
Segment Reporting Information [Line Items]
Operating Revenues	277,009	249,976	813,833	714,715
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	25,538	22,220	82,674	64,272
Income (Loss) from Operations	25,538	22,220	82,674	64,272
Depreciation of property, plant and equipment	7,202	7,599	21,735	20,832
Pension Service Cost	198	83	527	244
Capital Expenditures	4,734	6,445	16,254	19,747
Identifiable Assets	1,553,897		1,553,897		1,537,989
Operating Segments [Member] | Education [Member] | Higher Education [Member] | Reportable Subsegments [Member]
Segment Reporting Information [Line Items]
Operating Revenues	85,655	81,925	246,818	250,557
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	11,385	8,465	31,258	33,343
Income (Loss) from Operations	11,385	8,465	31,258	33,343
Depreciation of property, plant and equipment	589	1,258	2,291	3,431
Pension Service Cost	1,903	958	5,729	2,803
Capital Expenditures	535	999	768	1,637
Identifiable Assets	205,409		205,409		187,972
Operating Segments [Member] | Education [Member] | Supplemental Education [Member] | Reportable Subsegments [Member]
Segment Reporting Information [Line Items]
Operating Revenues	76,134	78,332	221,389	226,535
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	11,186	9,729	21,438	16,992
Income (Loss) from Operations	11,186	9,729	21,438	16,992
Depreciation of property, plant and equipment	777	1,117	2,653	4,087
Pension Service Cost	1,962	1,063	5,874	3,110
Capital Expenditures	542	872	1,446	2,110
Identifiable Assets	230,742		230,742		249,519
Operating Segments [Member] | Television Broadcasting [Member]
Segment Reporting Information [Line Items]
Operating Revenues	145,422	116,112	373,958	347,818
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	63,274	33,310	126,745	97,808
Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	1,360	1,363	4,070	4,088
Income (Loss) from Operations	61,914	31,947	122,675	93,720
Depreciation of property, plant and equipment	2,756	3,120	8,494	9,243
Pension Service Cost	1,528	833	4,583	2,498
Capital Expenditures	982	1,841	4,319	5,018
Identifiable Assets	412,391		412,391		419,557
Operating Segments [Member] | Manufacturing [Member]
Segment Reporting Information [Line Items]
Operating Revenues	95,385	109,216	300,914	343,882
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	7,114	10,515	20,216	39,019
Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	2,619	51,489	8,387	60,683
Income (Loss) from Operations	4,495	(40,974)	11,829	(21,664)
Depreciation of property, plant and equipment	2,818	2,388	8,227	6,957
Pension Service Cost	978	280	1,897	836
Capital Expenditures	3,817	4,380	12,085	14,971
Identifiable Assets	416,089		416,089		431,712
Operating Segments [Member] | Healthcare [Member]
Segment Reporting Information [Line Items]
Operating Revenues	155,413	116,164	431,142	331,505
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	14,419	6,837	34,481	19,986
Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	159	866	1,393	2,702
Income (Loss) from Operations	14,260	5,971	33,088	17,284
Depreciation of property, plant and equipment	1,754	1,411	5,031	3,802
Pension Service Cost	4,804	3,521	14,413	10,563
Capital Expenditures	4,016	4,579	8,842	9,732
Identifiable Assets	306,049		306,049		265,150
Operating Segments [Member] | Automotive [Member]
Segment Reporting Information [Line Items]
Operating Revenues	289,392	272,018	902,046	765,251
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	9,069	8,240	28,929	28,543
Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	5	3	10	3
Income (Loss) from Operations	9,064	8,237	28,919	28,540
Depreciation of property, plant and equipment	1,774	1,304	5,203	3,565
Pension Service Cost	29	16	86	26
Capital Expenditures	724	2,112	3,093	6,215
Identifiable Assets	592,274		592,274		597,267
Operating Segments [Member] | Other Businesses [Member]
Segment Reporting Information [Line Items]
Operating Revenues	83,464	86,653	253,753	269,110
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	(27,073)	(24,404)	(77,456)	(73,428)
Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	1,821	53,149	33,354	58,987
Income (Loss) from Operations	(28,894)	(77,553)	(110,810)	(132,415)
Depreciation of property, plant and equipment	3,522	3,832	11,909	10,882
Pension Service Cost	1,963	662	5,577	1,847
Capital Expenditures	6,401	5,508	16,776	12,120
Identifiable Assets	333,937		333,937		368,542
Corporate Office [Member]
Segment Reporting Information [Line Items]
Operating Revenues	576	365	1,727	1,215
Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	(14,081)	(14,599)	(43,454)	(39,881)
Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets	0	0	0	0
Income (Loss) from Operations	(14,081)	(14,599)	(43,454)	(39,881)
Depreciation of property, plant and equipment	132	152	432	458
Pension Service Cost	1,014	952	3,043	2,856
Capital Expenditures	2,020	6	2,425	9
Identifiable Assets	187,586		187,586		$ 93,760
Intersegment Elimination [Member]
Segment Reporting Information [Line Items]
Operating Revenues	$ (580)	$ (846)	$ (2,023)	$ (2,822)