Goodwill and Other Intangible Assets (Other Intangible Assets) (Details 2) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Amortized Intangible Assets [Line Items]
Gross Carrying Amount	$ 543,623	$ 544,128
Accumulated Amortization	396,070	382,706
Net Carrying Amount	147,553	161,422
Indefinite-Lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets	180,038	178,934
Franchise Agreements [Member]
Indefinite-Lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets	85,858	85,858
Trade Names and Trademarks [Member]
Indefinite-Lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets	83,009	81,905
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
Other [Member]
Indefinite-Lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets	21	21
Student and Customer Relationships [Member]
Amortized Intangible Assets [Line Items]
Gross Carrying Amount	298,022	297,766
Accumulated Amortization	236,486	230,429
Net Carrying Amount	$ 61,536	$ 67,337
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	$ 148,286	$ 148,102
Accumulated Amortization	84,833	81,078
Net Carrying Amount	$ 63,453	$ 67,024
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	15 years	15 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	11,112	10,367
Net Carrying Amount	6,288	7,033
Databases and Technology [Member]
Amortized Intangible Assets [Line Items]
Gross Carrying Amount	36,251	36,216
Accumulated Amortization	33,714	32,219
Net Carrying Amount	$ 2,537	$ 3,997
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	$ 20	$ 1,000
Accumulated Amortization	16	995
Net Carrying Amount	$ 4	$ 5
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	$ 43,644	$ 43,644
Accumulated Amortization	29,909	27,618
Net Carrying Amount	$ 13,735	$ 16,026
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