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 Include in Segment Income (Loss) from Operations	[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
Restructuring, Settlement and Impairment Provisions		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 Include in Segment Income (Loss) from Operations	[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
Restructuring, Settlement and Impairment Provisions		11,571		40,354
Operating Segments [Member] | Education [Member] | Kaplan Corporate and Other [Member]
Restructuring Cost and Reserve [Line Items]
Severance		0	[1]	0
Accelerated depreciation of property, plant and equipment				0
Total Restructuring Costs Include in Segment Income (Loss) from Operations	[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
Restructuring, Settlement and Impairment Provisions		694		883
Operating Segments [Member] | Education [Member] | Kaplan International [Member] | Reportable Subsegments [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 Include in Segment Income (Loss) from Operations	[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
Restructuring, Settlement and Impairment Provisions		959		12,162
Operating Segments [Member] | Education [Member] | Higher Education [Member] | Reportable Subsegments [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 Include in Segment Income (Loss) from Operations	[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
Restructuring, Settlement and Impairment Provisions		802		8,006
Operating Segments [Member] | Education [Member] | Test Preparation [Member] | Reportable Subsegments [Member]
Restructuring Cost and Reserve [Line Items]
Severance		913	[1]	913
Operating lease cost				2,740
Accelerated depreciation of property, plant and equipment				1,792
Total Restructuring Costs Include in Segment Income (Loss) from Operations	[1]			5,445
Lease right-of-use assets		1,710		1,953
Property, plant and equipment		206		206
Non-operating pensions and postretirement benefit income, net		4,829		4,829
Restructuring, Settlement and Impairment Provisions		7,658		12,433
Operating Segments [Member] | Education [Member] | Professional (U.S.) [Member] | Reportable Subsegments [Member]
Restructuring Cost and Reserve [Line Items]
Severance		0	[1]	0
Operating lease cost				556
Accelerated depreciation of property, plant and equipment				9
Total Restructuring Costs Include in Segment Income (Loss) from Operations	[1]			565
Lease right-of-use assets		0		1,955
Property, plant and equipment		0		597
Non-operating pensions and postretirement benefit income, net		1,458		3,753
Restructuring, Settlement and Impairment Provisions		1,458		6,870
Operating Segments [Member] | Other Businesses [Member]
Restructuring Cost and Reserve [Line Items]
Severance	[1]	0
Accelerated depreciation of property, plant and equipment				0
Total Restructuring Costs Include in Segment Income (Loss) from Operations	[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
Restructuring, Settlement and Impairment Provisions		$ 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.