Business Segments (Information by Operating Segment) (Details 1) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2025	Mar. 31, 2024		Dec. 31, 2024
Segment Reporting Information [Line Items]
Operating Revenues		$ 1,165,915	$ 1,152,662
Depreciation Expense		20,554	22,527
Amortization of Intangible Assets		(7,824)	(10,751)
Income from Operations		47,473	35,442
Equity in (losses) earnings of affiliates, net		(8,428)	2,331
Interest expense, net		(79,777)	(17,150)
Non-operating pension and postretirement benefit income, net		34,617	42,417
Gain on marketable equity securities, net		43,801	104,152
Other Income, Net		(4,065)	1,647
Income Before Income Taxes		33,621	168,839
Capital Expenditures		14,103	21,473
Investments in Marketable Equity Securities		901,059			$ 852,434
Investments in Affiliates		156,935			169,125
Prepaid Pension Cost		2,533,255			2,510,520
Total Assets		7,615,900			7,677,205
Operating Segments [Member] | Reportable Segment, Aggregation before Other Operating Segment [Member]
Segment Reporting Information [Line Items]
Operating Revenues		1,081,022	1,069,600
Cost of Revenue	[1]	576,246	574,821
Payroll and Fringe Benefits Expense	[2]	160,513	164,983
Occupancy Expense		29,793	32,385
Advertising and Marketing Expense		19,220	17,025
Networking and Programming Expenses		31,357	31,890
Management Services Expense		2,052	2,007	[3]
Other Segment Items	[4]	134,734	130,033
EBITDAP		127,107	116,456
Pension Service Cost		9,744	11,149
Depreciation Expense		16,610	18,195
Income from Operations before Amortization of Intangible Assets		100,753	87,112
Capital Expenditures		9,409	17,948
Identifiable Assets		3,575,553			3,667,911
Operating Segments [Member] | Education [Member]
Segment Reporting Information [Line Items]
Operating Revenues		424,731	422,598
Cost of Revenue	[1],[5]	166,087	169,539
Payroll and Fringe Benefits Expense	[2],[6]	113,320	113,897
Occupancy Expense		27,922	30,529
Advertising and Marketing Expense		19,220	17,025
Other Segment Items	[7],[8]	44,043	44,632
EBITDAP		54,139	46,976
Pension Service Cost		4,223	4,110
Depreciation Expense		7,764	9,305
Income from Operations before Amortization of Intangible Assets		42,152	33,561
Capital Expenditures		4,741	7,519
Identifiable Assets		1,894,026			1,963,878
Operating Segments [Member] | Education [Member] | Kaplan Corporate and Other [Member]
Segment Reporting Information [Line Items]
Operating Revenues		12	2,588
Payroll and Fringe Benefits Expense	[6]	5,010	5,673
Occupancy Expense		63	2,720
Advertising and Marketing Expense		128	98
Other Segment Items	[8]	1,065	1,307
EBITDAP		(6,254)	(7,210)
Pension Service Cost		388	348
Depreciation Expense		6	27
Income from Operations before Amortization of Intangible Assets		(6,648)	(7,585)
Capital Expenditures		0	0
Identifiable Assets		49,134			41,754
Operating Segments [Member] | Education [Member] | Intersubsegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating Revenues		(427)	(2,032)
Cost of Revenue	[5]	(427)	(1,935)
Other Segment Items	[8]	37	168
EBITDAP		(37)	(265)
Income from Operations before Amortization of Intangible Assets		(37)	(265)
Operating Segments [Member] | Education [Member] | Kaplan International [Member] | Reportable Subsegments [Member]
Segment Reporting Information [Line Items]
Operating Revenues		261,256	269,798
Cost of Revenue	[5]	88,097	91,653
Payroll and Fringe Benefits Expense	[6]	70,666	73,114
Occupancy Expense		27,025	26,996
Advertising and Marketing Expense		8,185	7,910
Other Segment Items	[9]	30,532	31,294
EBITDAP		36,751	38,831
Pension Service Cost		140	163
Depreciation Expense		6,549	7,356
Income from Operations before Amortization of Intangible Assets		30,062	31,312
Capital Expenditures		2,787	7,017
Identifiable Assets		1,420,247			1,500,846
Operating Segments [Member] | Education [Member] | Higher Education [Member] | Reportable Subsegments [Member]
Segment Reporting Information [Line Items]
Operating Revenues		88,487	80,122
Cost of Revenue	[5]	66,662	65,987
Payroll and Fringe Benefits Expense	[6]	4,477	4,001
Occupancy Expense		176	174
Advertising and Marketing Expense		1,877	1,623
Other Segment Items	[10]	224	134
EBITDAP		15,071	8,203
Pension Service Cost		1,808	1,781
Depreciation Expense		456	903
Income from Operations before Amortization of Intangible Assets		12,807	5,519
Capital Expenditures		173	59
Identifiable Assets		194,830			182,442
Operating Segments [Member] | Education [Member] | Supplemental Education [Member] | Reportable Subsegments [Member]
Segment Reporting Information [Line Items]
Operating Revenues		75,403	72,122
Cost of Revenue	[5]	11,755	13,834
Payroll and Fringe Benefits Expense	[6]	33,167	31,109
Occupancy Expense		658	639
Advertising and Marketing Expense		9,030	7,394
Other Segment Items	[11]	12,185	11,729
EBITDAP		8,608	7,417
Pension Service Cost		1,887	1,818
Depreciation Expense		753	1,019
Income from Operations before Amortization of Intangible Assets		5,968	4,580
Capital Expenditures		1,781	443
Identifiable Assets		229,815			238,836
Operating Segments [Member] | Television Broadcasting [Member]
Segment Reporting Information [Line Items]
Operating Revenues		103,554	113,058
Payroll and Fringe Benefits Expense	[2]	27,764	29,276
Networking and Programming Expenses		31,357	31,890
Other Segment Items	[12]	14,628	16,402
EBITDAP		29,805	35,490
Pension Service Cost		1,419	1,639
Depreciation Expense		2,628	2,868
Income from Operations before Amortization of Intangible Assets		25,758	30,983
Capital Expenditures		198	1,629
Identifiable Assets		399,304			402,200
Operating Segments [Member] | Automotive [Member]
Segment Reporting Information [Line Items]
Operating Revenues		280,991	303,840
Cost of Revenue	[1]	240,307	258,961
Payroll and Fringe Benefits Expense	[2]	19,429	21,810
Occupancy Expense		1,871	1,856
Management Services Expense	[3]	2,052	2,007
Other Segment Items	[13]	9,079	7,826
EBITDAP		8,253	11,380
Pension Service Cost		27	15
Depreciation Expense		1,729	1,713
Income from Operations before Amortization of Intangible Assets		6,497	9,652
Capital Expenditures		480	1,204
Identifiable Assets		548,738			582,105
Operating Segments [Member] | Manufacturing [Member]
Segment Reporting Information [Line Items]
Operating Revenues		98,005	101,903
Cost of Revenue	[1]	69,737	75,264
Other Segment Items	[14]	16,578	17,108
EBITDAP		11,690	9,531
Pension Service Cost		1,076	627
Depreciation Expense		2,703	2,715
Income from Operations before Amortization of Intangible Assets		7,911	6,189
Capital Expenditures		3,373	5,660
Identifiable Assets		415,822			411,137
Operating Segments [Member] | Healthcare [Member]
Segment Reporting Information [Line Items]
Operating Revenues		173,741	128,201
Cost of Revenue	[1]	100,115	71,057
Other Segment Items	[15]	50,406	44,065
EBITDAP		23,220	13,079
Pension Service Cost		2,999	4,758
Depreciation Expense		1,786	1,594
Income from Operations before Amortization of Intangible Assets		18,435	6,727
Capital Expenditures		617	1,936
Identifiable Assets		317,663			308,591
Operating Segments [Member] | Other Businesses [Member]
Segment Reporting Information [Line Items]
Income from Operations before Amortization of Intangible Assets	[16]	(29,447)	(26,283)
Identifiable Assets		335,956			338,089
Operating Segments [Member] | Other Businesses and Corporate Office [Member]
Segment Reporting Information [Line Items]
Operating Revenues	[17]	85,517	83,874
Capital Expenditures	[18]	4,694	3,525
Corporate Office [Member]
Segment Reporting Information [Line Items]
Income from Operations before Amortization of Intangible Assets		(16,009)	(14,636)
Identifiable Assets		113,142			$ 139,126
Intersegment Elimination [Member]
Segment Reporting Information [Line Items]
Operating Revenues		$ (624)	$ (812)

[1] Cost of revenue reflects the amounts reported and provided to the CODM and does not necessarily reconcile to the Company's Consolidated Statement of Operations or align across reportable segments. Cost of revenue excludes charges related to depreciation, which is shown separately above.

[2] Excludes pension service cost, which is shown separately above. Excludes any payroll and related benefits costs captured in cost of revenue.

[3] Management and operating services provided by Christopher J. Ourisman and his team of industry professionals.

[4] Other segment items for each reportable segment include:

[5] Cost of revenue reflects the amounts reported and provided to the CODM and does not necessarily reconcile to the Company's Consolidated Statement of Operations or align across reportable segments. Cost of revenue excludes charges related to depreciation, which is shown separately above.

[6] Excludes pension service cost, which is shown separately above. Excludes any payroll and related benefits costs captured in cost of revenue.

[7] Education (includes Kaplan International, Kaplan Higher Education and Kaplan Supplemental Education) - training and employment expense, travel meals and entertainment expense, operating fees and other general and administrative (G&A) expenses.

[8] Other segment items for each reportable segment include:

[9] Kaplan international - travel meals and entertainment expense, training and employment expense, operating fees and other G&A expenses.

[10] Higher education - training and employment expense, operating fees and other G&A expenses.

[11] Supplemental education - training and employment expense, operating fees and other G&A expenses.

[12] Television Broadcasting - other broadcast expenses, facilities expenses, third-party commission costs and other selling, general and administrative (SG&A) expenses.

[13] Automotive - advertising and marketing expense and other G&A expenses.

[14] Manufacturing - payroll and fringe benefits expense (SG&A) and other SG&A expenses.

[15] Healthcare - indirect costs (e.g. payroll and benefits expenses, general and administrative expenses) and other SG&A expenses.

[16] Profit or loss from operating segments below the quantitative thresholds attributable to Other Businesses as described above. These operating segments did not meet any of the quantitative thresholds for determining reportable segments.

[17] Revenue from segments below the quantitative thresholds is attributable to Other Businesses and the Corporate Office, as described above. None of these operating segments meet the quantitative thresholds for determining reportable segments.

[18] Capital Expenditures from operating segments below the quantitative thresholds are attributable to Other Businesses and the Corporate Office, as described above. None of these operating segments meet the quantitative thresholds for determining reportable segments.