Acquisitions and Dispositions of Businesses (Significant Component) (Details 3) - Kaplan University Transaction [Member] - Higher Education [Member] - Education [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Not Discontinued Operation, Revenue	$ 91,526	$ 430,645	$ 500,914
Disposal Group, Not Discontinued Operation, Operating Income	$ 213	$ 17,869	$ 39,498