Goodwill and Other Intangible Assets (Other Intangible Assets) (Details 2) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Amortized Intangible Assets [Line Items]
Gross Carrying Amount	$ 467,525		$ 452,952
Accumulated Amortization	232,517		219,471
Net Carrying Amount	235,008		233,481
Indefinite-Lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets	116,172		140,197
Trade Names and Trademarks [Member]
Indefinite-Lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets	83,164		100,491
Franchise Agreements [Member]
Indefinite-Lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets	21,858		28,556
FCC licenses [Member]
Indefinite-Lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets	11,000		11,000
Licensure and Accreditation [Member]
Indefinite-Lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets	150		150
Student and Customer Relationships [Member]
Amortized Intangible Assets [Line Items]
Gross Carrying Amount	292,305		291,626
Accumulated Amortization	152,705		144,625
Net Carrying Amount	$ 139,600		147,001
Student and Customer Relationships [Member] | Minimum [Member]
Amortized Intangible Assets [Line Items]
Useful Life	2 years	2 years
Student and Customer Relationships [Member] | Maximum [Member]
Amortized Intangible Assets [Line Items]
Useful Life	10 years	10 years
Trade Names and Trademarks [Member]
Amortized Intangible Assets [Line Items]
Gross Carrying Amount	$ 99,989		87,190
Accumulated Amortization	45,176		42,770
Net Carrying Amount	$ 54,813		44,420
Trade Names and Trademarks [Member] | Minimum [Member]
Amortized Intangible Assets [Line Items]
Useful Life	2 years	2 years
Trade Names and Trademarks [Member] | Maximum [Member]
Amortized Intangible Assets [Line Items]
Useful Life	10 years	10 years
Network Affiliation Agreements [Member]
Amortized Intangible Assets [Line Items]
Useful Life	10 years	10 years
Gross Carrying Amount	$ 17,400		17,400
Accumulated Amortization	5,583		5,148
Net Carrying Amount	11,817		12,252
Databases and Technology [Member]
Amortized Intangible Assets [Line Items]
Gross Carrying Amount	31,881		30,623
Accumulated Amortization	14,096		12,850
Net Carrying Amount	$ 17,785		17,773
Databases and Technology [Member] | Minimum [Member]
Amortized Intangible Assets [Line Items]
Useful Life	3 years	3 years
Databases and Technology [Member] | Maximum [Member]
Amortized Intangible Assets [Line Items]
Useful Life	6 years	6 years
Non-compete Agreements [Member]
Amortized Intangible Assets [Line Items]
Gross Carrying Amount	$ 1,150		1,313
Accumulated Amortization	804		929
Net Carrying Amount	$ 346		384
Non-compete Agreements [Member] | Minimum [Member]
Amortized Intangible Assets [Line Items]
Useful Life	2 years	2 years
Non-compete Agreements [Member] | Maximum [Member]
Amortized Intangible Assets [Line Items]
Useful Life	5 years	5 years
Other [Member]
Amortized Intangible Assets [Line Items]
Gross Carrying Amount	$ 24,800		24,800
Accumulated Amortization	14,153		13,149
Net Carrying Amount	$ 10,647		$ 11,651
Other [Member] | Minimum [Member]
Amortized Intangible Assets [Line Items]
Useful Life	1 year	1 year
Other [Member] | Maximum [Member]
Amortized Intangible Assets [Line Items]
Useful Life	8 years	8 years