Business Segments (Narrative) (Details) $ in Thousands		12 Months Ended
	Mar. 22, 2018 USD ($)	Dec. 31, 2022 USD ($) automotiveDealership segment televisionStation restaurant	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment		7
Operating Revenues		$ 3,924,493	$ 3,185,974	$ 2,889,121
Clyde's Restaurant Group [Member]
Segment Reporting Information [Line Items]
Accelerated Depreciation				5,700
Non U.S. [Member]
Segment Reporting Information [Line Items]
Operating Revenues		776,000	709,000	642,000
Foreign assets		477,000	476,000
Education [Member]
Segment Reporting Information [Line Items]
Accrued restructuring costs			1,200
Education [Member] | UNITED KINGDOM
Segment Reporting Information [Line Items]
Operating Revenues		$ 448,000	$ 404,000	$ 375,000
Television Broadcasting [Member]
Segment Reporting Information [Line Items]
Number of television broadcast stations owned | televisionStation		7
Automotive [Member]
Segment Reporting Information [Line Items]
Number of dealerships | automotiveDealership		6
Other Businesses [Member]
Segment Reporting Information [Line Items]
Number of Restaurants | restaurant		11
Kaplan University Transaction [Member] | Education [Member] | Higher Education [Member] | Purdue University Global [Member]
Segment Reporting Information [Line Items]
Accounts receivable		$ 90,000
Accounts receivable, noncurrent		$ 19,400
Advance Related To Kaplan University Transaction	$ 20,000