Revenue from Contracts with Customers (Disaggregation of Revenue) (Details 1) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation of Revenue [Line Items]
Revenue	$ 2,695,966	$ 2,591,846	$ 2,481,890
Intersegment Elimination [Member]
Disaggregation of Revenue [Line Items]
Revenue	(100)	(51)	(139)
Kaplan International [Member]
Disaggregation of Revenue [Line Items]
Revenue	719,982	697,999	696,362
Higher Education [Member]
Disaggregation of Revenue [Line Items]
Revenue	342,085	431,425	501,784
Test Preparation [Member]
Disaggregation of Revenue [Line Items]
Revenue	256,102	273,298	286,556
Professional (U.S.) [Member]
Disaggregation of Revenue [Line Items]
Revenue	134,187	115,839	115,263
Kaplan Corporate and Other [Member]
Disaggregation of Revenue [Line Items]
Revenue	1,142	294	214
Education Intersegment Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenue	(2,483)	(2,079)	(1,718)
Education [Member]
Disaggregation of Revenue [Line Items]
Revenue	1,451,015	1,516,776	1,598,461
Television Broadcasting [Member]
Disaggregation of Revenue [Line Items]
Revenue	505,549	409,916	409,718
Manufacturing [Member]
Disaggregation of Revenue [Line Items]
Revenue	487,619	414,193	241,604
Health Care [Member]
Disaggregation of Revenue [Line Items]
Revenue	149,275	154,202	146,962
SocialCode [Member]
Disaggregation of Revenue [Line Items]
Revenue	58,728	62,077	58,851
Other Businesses [Member]
Disaggregation of Revenue [Line Items]
Revenue	$ 43,880	$ 34,733	$ 26,433