Acquisitions and Dispositions - 2020 Acquisitions - Additional Information (Details) $ in Thousands						3 Months Ended			7 Months Ended	9 Months Ended		12 Months Ended
	Sep. 17, 2020 USD ($)	Sep. 01, 2020 USD ($)	Mar. 02, 2020 USD ($)	Jan. 27, 2020 USD ($)	Sep. 19, 2019 USD ($)	Sep. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Dec. 31, 2019	Mar. 30, 2020 TelevisionStation
Business Acquisition [Line Items]
Operating income						$ 343,597		$ 121,615		$ 844,865	$ 398,633
Network affiliation agreements [Member]
Business Acquisition [Line Items]
Network affiliation agreements useful life										15 years		15 years
Other definite-lived intangible assets [Member]
Business Acquisition [Line Items]
Weighted average estimated useful life of intangible assets										9 years
Mission [Member] | Asset Purchase Agreement [Member] | Marshall Broadcasting Group, Inc [Member]
Business Acquisition [Line Items]
Cash payment		$ 4,200
Number of television stations owned | TelevisionStation													3
Purchase price		53,200
Purchase price settled against existing loans receivable		$ 49,000
Carryover of tax basis in goodwill, deductible for tax purposes						3,300			$ 3,300	$ 3,300
Mission [Member] | Asset Purchase Agreement [Member] | Marshall Broadcasting Group, Inc [Member] | FCC Licenses [Member]
Business Acquisition [Line Items]
Carryover of tax basis in intangible assets, deductible for tax purposes						13,300			13,300	13,300
Tribune [Member]
Business Acquisition [Line Items]
Acquisition date					Sep. 19, 2019
Cash payment					$ 4,197,198
Purchase price					7,187,039
Carryover of tax basis in goodwill, deductible for tax purposes					634,000
Revenue included in consolidated statements of operations and comprehensive income							$ 471,600
Operating income							$ 78,400
Merger related costs								$ 31,000			$ 38,300
Tribune [Member] | FCC Licenses [Member]
Business Acquisition [Line Items]
Carryover of tax basis in intangible assets, deductible for tax purposes					60,000
Tribune [Member] | Network affiliation agreements [Member]
Business Acquisition [Line Items]
Carryover of tax basis in intangible assets, deductible for tax purposes					$ 102,000
Network affiliation agreements useful life					15 years
Tribune [Member] | Other definite-lived intangible assets [Member]
Business Acquisition [Line Items]
Carryover of tax basis in intangible assets, deductible for tax purposes					$ 288,000
Weighted average estimated useful life of intangible assets					9 years
KGBT-TV [Member]
Business Acquisition [Line Items]
Cash payment				$ 17,900
Television Station WJZY [Member]
Business Acquisition [Line Items]
Acquisition date			Mar. 02, 2020
Television Station WMYT [Member]
Business Acquisition [Line Items]
Acquisition date			Mar. 02, 2020
Television Station WJZY and WMYT [Member]
Business Acquisition [Line Items]
Cash payment			$ 45,300
WDKY-TV [Member]
Business Acquisition [Line Items]
Acquisition date	Sep. 17, 2020
Cash payment	$ 18,000
Net assets acquired	37,000
Bargain purchase gain	$ 19,000
KGBT, WJZY/WMYT and WDKY [Member]
Business Acquisition [Line Items]
Carryover of tax basis in goodwill, deductible for tax purposes						4,300			4,300	4,300
KGBT, WJZY/WMYT and WDKY [Member] | FCC Licenses [Member]
Business Acquisition [Line Items]
Carryover of tax basis in intangible assets, deductible for tax purposes						25,900			25,900	25,900
2020 Acquisitions [Member]
Business Acquisition [Line Items]
Net assets acquired						134,384			134,384	134,384
Revenue included in consolidated statements of operations and comprehensive income									47,200
Operating income									$ 17,900
Merger related costs						$ 1,700				$ 4,300