Goodwill and Other Intangible Assets (Other Intangible Assets) (Details 2) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017
Amortized Intangible Assets [Line Items]
Gross Carrying Amount		$ 440,105	$ 362,073
Accumulated Amortization		176,844	124,097
Net Carrying Amount		263,261	237,976
Indefinite-lived Intangible Assets [Line Items]
Net Carrying Amount		99,052	102,195
Student and Customer Relationships [Member]
Amortized Intangible Assets [Line Items]
Gross Carrying Amount	[1]	282,761	260,464
Accumulated Amortization	[1]	114,429	83,690
Net Carrying Amount	[1]	168,332	176,774
Trade Names and Trademarks [Member]
Amortized Intangible Assets [Line Items]
Gross Carrying Amount		87,285	50,286
Accumulated Amortization		39,825	25,596
Net Carrying Amount		$ 47,460	$ 24,690
Network affiliation agreements [Member]
Amortized Intangible Assets [Line Items]
Useful Life (in years)		10 years	10 years
Gross Carrying Amount		$ 17,400	$ 17,400
Accumulated Amortization		3,408	1,668
Net Carrying Amount		13,992	15,732
Databases and Technology [Member]
Amortized Intangible Assets [Line Items]
Gross Carrying Amount		27,041	19,563
Accumulated Amortization		8,471	5,008
Net Carrying Amount		18,570	14,555
Non-compete Agreements [Member]
Amortized Intangible Assets [Line Items]
Gross Carrying Amount		1,088	930
Accumulated Amortization		838	467
Net Carrying Amount		250	463
Other [Member]
Amortized Intangible Assets [Line Items]
Gross Carrying Amount		24,530	13,430
Accumulated Amortization		9,873	7,668
Net Carrying Amount		$ 14,657	$ 5,762
Minimum [Member] | Student and Customer Relationships [Member]
Amortized Intangible Assets [Line Items]
Useful Life (in years)	[1]	2 years	1 year
Minimum [Member] | Trade Names and Trademarks [Member]
Amortized Intangible Assets [Line Items]
Useful Life (in years)		2 years	2 years
Minimum [Member] | Databases and Technology [Member]
Amortized Intangible Assets [Line Items]
Useful Life (in years)		3 years	3 years
Minimum [Member] | Non-compete Agreements [Member]
Amortized Intangible Assets [Line Items]
Useful Life (in years)		2 years	2 years
Minimum [Member] | Other [Member]
Amortized Intangible Assets [Line Items]
Useful Life (in years)		1 year	1 year
Maximum [Member]
Amortized Intangible Assets [Line Items]
Useful Life (in years)		10 years
Maximum [Member] | Student and Customer Relationships [Member]
Amortized Intangible Assets [Line Items]
Useful Life (in years)	[1]	10 years	10 years
Maximum [Member] | Trade Names and Trademarks [Member]
Amortized Intangible Assets [Line Items]
Useful Life (in years)		10 years	10 years
Maximum [Member] | Databases and Technology [Member]
Amortized Intangible Assets [Line Items]
Useful Life (in years)		6 years	6 years
Maximum [Member] | Non-compete Agreements [Member]
Amortized Intangible Assets [Line Items]
Useful Life (in years)		5 years	5 years
Maximum [Member] | Other [Member]
Amortized Intangible Assets [Line Items]
Useful Life (in years)		8 years	8 years
Trade Names and Trademarks [Member]
Indefinite-lived Intangible Assets [Line Items]
Net Carrying Amount		$ 80,102	$ 82,745
FCC licenses [Member]
Indefinite-lived Intangible Assets [Line Items]
Net Carrying Amount		18,800	18,800
Licensure and Accreditation [Member]
Indefinite-lived Intangible Assets [Line Items]
Net Carrying Amount		$ 150	$ 650

[1] As of December 31, 2017, the student and customer relationships’ minimum useful life was 1 year.