Goodwill and Other Intangible Assets (Changes in Carrying Amount of Goodwill) (Details 1) $ in Thousands	9 Months Ended
	Sep. 30, 2018 USD ($)
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 1,665,861
Accumulated impairment losses, beginning balance	(366,151)
Goodwill, net, beginning balance	1,299,710
Acquisitions	41,397
Dispositions	(11,191)
Foreign currency exchange rate changes	(19,841)
Goodwill, ending balance	1,656,527
Accumulated impairment losses, ending balance	(346,452)
Goodwill, net, ending balance	1,310,075
Education [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	1,171,812
Accumulated impairment losses, beginning balance	(350,850)
Goodwill, net, beginning balance	820,962
Acquisitions	19,981
Dispositions	(11,191)
Foreign currency exchange rate changes	(19,841)
Goodwill, ending balance	1,141,062
Accumulated impairment losses, ending balance	(331,151)
Goodwill, net, ending balance	809,911
Education [Member] | Kaplan International [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	615,861
Accumulated impairment losses, beginning balance	0
Goodwill, net, beginning balance	615,861
Acquisitions	26
Dispositions	0
Foreign currency exchange rate changes	(19,775)
Goodwill, ending balance	596,112
Accumulated impairment losses, ending balance	0
Goodwill, net, ending balance	596,112
Education [Member] | Higher Education [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	205,494
Accumulated impairment losses, beginning balance	(131,023)
Goodwill, net, beginning balance	74,471
Acquisitions	0
Dispositions	(11,191)
Foreign currency exchange rate changes	(40)
Goodwill, ending balance	174,564
Accumulated impairment losses, ending balance	(111,324)
Goodwill, net, ending balance	63,240
Education [Member] | Test Preparation [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	166,098
Accumulated impairment losses, beginning balance	(102,259)
Goodwill, net, beginning balance	63,839
Acquisitions	626
Dispositions	0
Foreign currency exchange rate changes	0
Goodwill, ending balance	166,724
Accumulated impairment losses, ending balance	(102,259)
Goodwill, net, ending balance	64,465
Education [Member] | Professional (U.S.) [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	184,359
Accumulated impairment losses, beginning balance	(117,568)
Goodwill, net, beginning balance	66,791
Acquisitions	19,329
Dispositions	0
Foreign currency exchange rate changes	(26)
Goodwill, ending balance	203,662
Accumulated impairment losses, ending balance	(117,568)
Goodwill, net, ending balance	86,094
Television Broadcasting [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	190,815
Accumulated impairment losses, beginning balance	0
Goodwill, net, beginning balance	190,815
Acquisitions	0
Dispositions	0
Foreign currency exchange rate changes	0
Goodwill, ending balance	190,815
Accumulated impairment losses, ending balance	0
Goodwill, net, ending balance	190,815
Healthcare [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	69,409
Accumulated impairment losses, beginning balance	0
Goodwill, net, beginning balance	69,409
Acquisitions	217
Dispositions	0
Foreign currency exchange rate changes	0
Goodwill, ending balance	69,626
Accumulated impairment losses, ending balance	0
Goodwill, net, ending balance	69,626
Other Businesses [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	233,825
Accumulated impairment losses, beginning balance	(15,301)
Goodwill, net, beginning balance	218,524
Acquisitions	21,199
Dispositions	0
Foreign currency exchange rate changes	0
Goodwill, ending balance	255,024
Accumulated impairment losses, ending balance	(15,301)
Goodwill, net, ending balance	$ 239,723