Goodwill and Other Intangible Assets (Changes in Carrying Amount of Goodwill) (Details 1) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 1,644,164	$ 1,665,861
Accumulated impairment losses, beginning balance	(346,452)	(366,151)
Goodwill, net, beginning balance	1,297,712	1,299,710
Acquisitions	84,515	41,840
Dispositions	(579)	(11,191)
Foreign currency exchange rate changes	6,631	(32,647)
Goodwill, ending balance	1,734,731	1,644,164
Accumulated impairment losses, ending balance	(346,452)	(346,452)
Goodwill, net, ending balance	1,388,279	1,297,712
Education [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	1,128,699	1,171,812
Accumulated impairment losses, beginning balance	(331,151)	(350,850)
Goodwill, net, beginning balance	797,548	820,962
Acquisitions	6,207	20,424
Dispositions	(579)	(11,191)
Foreign currency exchange rate changes	6,631	(32,647)
Goodwill, ending balance	1,140,958	1,128,699
Accumulated impairment losses, ending balance	(331,151)	(331,151)
Goodwill, net, ending balance	809,807	797,548
Education [Member] | Kaplan International [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	583,424	615,861
Accumulated impairment losses, beginning balance	0	0
Goodwill, net, beginning balance	583,424	615,861
Acquisitions	6,207	62
Dispositions	(579)	0
Foreign currency exchange rate changes	6,552	(32,499)
Goodwill, ending balance	595,604	583,424
Accumulated impairment losses, ending balance	0	0
Goodwill, net, ending balance	595,604	583,424
Education [Member] | Higher Education [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	174,564	205,494
Accumulated impairment losses, beginning balance	(111,324)	(131,023)
Goodwill, net, beginning balance	63,240	74,471
Acquisitions	0	0
Dispositions	0	(11,191)
Foreign currency exchange rate changes	0	(40)
Goodwill, ending balance	174,564	174,564
Accumulated impairment losses, ending balance	(111,324)	(111,324)
Goodwill, net, ending balance	63,240	63,240
Education [Member] | Test Preparation [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	166,920	166,098
Accumulated impairment losses, beginning balance	(102,259)	(102,259)
Goodwill, net, beginning balance	64,661	63,839
Acquisitions	0	822
Dispositions	0	0
Foreign currency exchange rate changes	0	0
Goodwill, ending balance	166,920	166,920
Accumulated impairment losses, ending balance	(102,259)	(102,259)
Goodwill, net, ending balance	64,661	64,661
Education [Member] | Professional (U.S.) [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	203,791	184,359
Accumulated impairment losses, beginning balance	(117,568)	(117,568)
Goodwill, net, beginning balance	86,223	66,791
Acquisitions	0	19,540
Dispositions	0	0
Foreign currency exchange rate changes	79	(108)
Goodwill, ending balance	203,870	203,791
Accumulated impairment losses, ending balance	(117,568)	(117,568)
Goodwill, net, ending balance	86,302	86,223
Television Broadcasting [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	190,815	190,815
Accumulated impairment losses, beginning balance	0	0
Goodwill, net, beginning balance	190,815	190,815
Acquisitions	0	0
Dispositions	0	0
Foreign currency exchange rate changes	0	0
Goodwill, ending balance	190,815	190,815
Accumulated impairment losses, ending balance	0	0
Goodwill, net, ending balance	190,815	190,815
Manufacturing [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	231,479	220,041
Accumulated impairment losses, beginning balance	(7,616)	(7,616)
Goodwill, net, beginning balance	223,863	212,425
Acquisitions	3,514	11,438
Dispositions	0	0
Foreign currency exchange rate changes	0	0
Goodwill, ending balance	234,993	231,479
Accumulated impairment losses, ending balance	(7,616)	(7,616)
Goodwill, net, ending balance	227,377	223,863
Graham Healthcare Group [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	69,626	69,409
Accumulated impairment losses, beginning balance	0	0
Goodwill, net, beginning balance	69,626	69,409
Acquisitions	28,795	217
Dispositions	0	0
Foreign currency exchange rate changes	0	0
Goodwill, ending balance	98,421	69,626
Accumulated impairment losses, ending balance	0	0
Goodwill, net, ending balance	98,421	69,626
SocialCode [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	15,860	6,099
Accumulated impairment losses, beginning balance	0	0
Goodwill, net, beginning balance	15,860	6,099
Acquisitions	0	9,761
Dispositions	0	0
Foreign currency exchange rate changes	0	0
Goodwill, ending balance	15,860	15,860
Accumulated impairment losses, ending balance	0	0
Goodwill, net, ending balance	15,860	15,860
Other Businesses [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	7,685	7,685
Accumulated impairment losses, beginning balance	(7,685)	(7,685)
Goodwill, net, beginning balance	0	0
Acquisitions	45,999	0
Dispositions	0	0
Foreign currency exchange rate changes	0	0
Goodwill, ending balance	53,684	7,685
Accumulated impairment losses, ending balance	(7,685)	(7,685)
Goodwill, net, ending balance	$ 45,999	$ 0