Business Segments (Restructuring) (Details 1) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2020		Sep. 30, 2020
Restructuring Cost and Reserve [Line Items]
Severance		$ 1,872	[1]	$ 3,096
Operating lease cost				9,156
Accelerated depreciation of property, plant and equipment				3,368
Total Restructuring Costs Included in Segment Income (Loss) from Operations (1)	[1]			15,620
Lease right-of-use assets		1,710		11,165
Property, plant and equipment		206		2,262
Non-operating pensions and postretirement benefit income, net		7,783		13,797
Total Restructuring Related Costs		11,571		42,844
Operating Segments [Member] | Education [Member]
Restructuring Cost and Reserve [Line Items]
Severance		1,872	[1]	3,096
Operating lease cost				9,156
Accelerated depreciation of property, plant and equipment				3,368
Total Restructuring Costs Included in Segment Income (Loss) from Operations (1)	[1]			15,620
Lease right-of-use assets		1,710		9,760
Property, plant and equipment		206		2,176
Non-operating pensions and postretirement benefit income, net		7,783		12,798
Total Restructuring Related Costs		11,571		40,354
Operating Segments [Member] | Education [Member] | Reportable Subsegments [Member] | Kaplan International [Member]
Restructuring Cost and Reserve [Line Items]
Severance		959	[1]	2,183
Operating lease cost				2,418
Accelerated depreciation of property, plant and equipment				1,472
Total Restructuring Costs Included in Segment Income (Loss) from Operations (1)	[1]			6,073
Lease right-of-use assets		0		3,790
Property, plant and equipment		0		1,199
Non-operating pensions and postretirement benefit income, net		0		1,100
Total Restructuring Related Costs		959		12,162
Operating Segments [Member] | Education [Member] | Reportable Subsegments [Member] | Higher Education [Member]
Restructuring Cost and Reserve [Line Items]
Severance		0	[1]	0
Operating lease cost				3,442
Accelerated depreciation of property, plant and equipment				95
Total Restructuring Costs Included in Segment Income (Loss) from Operations (1)	[1]			3,537
Lease right-of-use assets		0		2,062
Property, plant and equipment		0		174
Non-operating pensions and postretirement benefit income, net		802		2,233
Total Restructuring Related Costs		802		8,006
Operating Segments [Member] | Education [Member] | Reportable Subsegments [Member] | Supplemental Education [Member]
Restructuring Cost and Reserve [Line Items]
Severance		913	[1]	913
Operating lease cost				3,296
Accelerated depreciation of property, plant and equipment				1,801
Total Restructuring Costs Included in Segment Income (Loss) from Operations (1)	[1]			6,010
Lease right-of-use assets		1,710		3,908
Property, plant and equipment		206		803
Non-operating pensions and postretirement benefit income, net		6,287		8,582
Total Restructuring Related Costs		9,116		19,303
Operating Segments [Member] | Education [Member] | Kaplan Corporate and Other [Member]
Restructuring Cost and Reserve [Line Items]
Severance		0	[1]	0
Operating lease cost				0
Accelerated depreciation of property, plant and equipment				0
Total Restructuring Costs Included in Segment Income (Loss) from Operations (1)	[1]			0
Lease right-of-use assets		0		0
Property, plant and equipment		0		0
Non-operating pensions and postretirement benefit income, net		694		883
Total Restructuring Related Costs		694		883
Operating Segments [Member] | Other Businesses [Member]
Restructuring Cost and Reserve [Line Items]
Severance		0	[1]	0
Operating lease cost				0
Accelerated depreciation of property, plant and equipment				0
Total Restructuring Costs Included in Segment Income (Loss) from Operations (1)	[1]			0
Lease right-of-use assets		0		1,405
Property, plant and equipment		0		86
Non-operating pensions and postretirement benefit income, net		0		999
Total Restructuring Related Costs		$ 0		$ 2,490

[1] These amounts are included in the segments’ Income (Loss) from Operations before Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets