Business Segments (Restructuring Costs) (Details 1) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restructuring Cost and Reserve [Line Items]
Severance		$ 6,163
Operating Lease Cost		9,942
Accelerated depreciation of property, plant and equipment		3,573
Total Restructuring Costs Included in Segment Results	[1]	19,678
Lease right-of-use assets		11,448	$ 1,100
Property, plant and equipment		2,321	$ 300	$ 200
Non-operating pension and postretirement benefit income, net		13,781
Total Restructuring Related Costs		47,228
Operating Segments [Member] | Education [Member]
Restructuring Cost and Reserve [Line Items]
Severance		6,163
Operating Lease Cost		9,942
Accelerated depreciation of property, plant and equipment		3,573
Total Restructuring Costs Included in Segment Results	[1]	19,678
Lease right-of-use assets		10,043
Property, plant and equipment		2,235
Non-operating pension and postretirement benefit income, net		12,782
Total Restructuring Related Costs		44,738
Operating Segments [Member] | Education [Member] | Reportable Subsegments [Member] | Kaplan International [Member]
Restructuring Cost and Reserve [Line Items]
Severance		4,366
Operating Lease Cost		2,905
Accelerated depreciation of property, plant and equipment		1,620
Total Restructuring Costs Included in Segment Results	[1]	8,891
Lease right-of-use assets		3,976
Property, plant and equipment		1,248
Non-operating pension and postretirement benefit income, net		1,100
Total Restructuring Related Costs		15,215
Operating Segments [Member] | Education [Member] | Reportable Subsegments [Member] | Higher Education [Member]
Restructuring Cost and Reserve [Line Items]
Severance		0
Operating Lease Cost		3,451
Accelerated depreciation of property, plant and equipment		152
Total Restructuring Costs Included in Segment Results	[1]	3,603
Lease right-of-use assets		2,062
Property, plant and equipment		174
Non-operating pension and postretirement benefit income, net		2,233
Total Restructuring Related Costs		8,072
Operating Segments [Member] | Education [Member] | Reportable Subsegments [Member] | Supplemental Education [Member]
Restructuring Cost and Reserve [Line Items]
Severance		1,797
Operating Lease Cost		3,586
Accelerated depreciation of property, plant and equipment		1,801
Total Restructuring Costs Included in Segment Results	[1]	7,184
Lease right-of-use assets		4,005
Property, plant and equipment		813
Non-operating pension and postretirement benefit income, net		8,566
Total Restructuring Related Costs		20,568
Operating Segments [Member] | Education [Member] | Kaplan Corporate and Other [Member]
Restructuring Cost and Reserve [Line Items]
Severance		0
Accelerated depreciation of property, plant and equipment		0
Total Restructuring Costs Included in Segment Results	[1]	0
Lease right-of-use assets		0
Property, plant and equipment		0
Non-operating pension and postretirement benefit income, net		883
Total Restructuring Related Costs		883
Operating Segments [Member] | Other Businesses [Member]
Restructuring Cost and Reserve [Line Items]
Severance		0
Accelerated depreciation of property, plant and equipment		0
Total Restructuring Costs Included in Segment Results	[1]	0
Lease right-of-use assets		1,405
Property, plant and equipment		86
Non-operating pension and postretirement benefit income, net		999
Total Restructuring Related Costs		$ 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.