Goodwill and Other Intangible Assets - Additional Information (Detail)		3 Months Ended				12 Months Ended
	Oct. 01, 2020 USD ($) License	Dec. 31, 2020 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2020 USD ($) Segment	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Oct. 01, 2019 USD ($)
Goodwill [Line Items]
Aggregate amortization expense						$ 4,000,000.0	$ 6,000,000.0	$ 6,100,000
Number of reporting segments | Segment						3
Impairment of goodwill						$ 800,000	27,714,000
Goodwill		$ 58,043,000				58,043,000	46,511,000	74,292,000
Digital
Goodwill [Line Items]
Impairment of goodwill		0			$ 800,000	800,000	27,714,000
Goodwill	$ 5,200,000	$ 17,494,000				17,494,000	5,962,000	33,743,000
Goodwill, impaired, method for fair value determination		As of the annual goodwill testing date, October 1, 2020, there was $5.2 million of goodwill in the digital reporting unit. The fair value of the digital reporting unit exceeded its carrying value by 20%, resulting in no impairment charge in the fourth quarter of 2020. The calculation of the fair value of the reporting unit requires estimates of the discount rate and the long term projected growth rate. If that discount rate were to increase by 1%, the fair value of the digital reporting unit would decrease by 5%.  If the long term projected growth rate were to decrease by 0.5%, the fair value of the digital reporting unit would decrease by 1%.
Percentage of fair value of assets		20.00%
Impairment charges related to intangible subject to amortization		$ 0	$ 0	$ 0	5,300,000
Impairment charges related to property and equipment					1,500,000
Television
Goodwill [Line Items]
Impairment of goodwill						0
Goodwill		40,549,000				$ 40,549,000	40,549,000	$ 40,549,000	$ 40,500,000
Goodwill, impaired, method for fair value determination						the television reporting unit fair value exceeded its carrying value by 19%, resulting in no impairment charge in 2020. The calculation of the fair value of the reporting unit requires estimates of the discount rate and the long term projected growth rate. If that discount rate were to increase by 0.5%, the fair value of the television reporting unit would decrease by 5%.  If the long term projected growth rate were to decrease by 0.5%, the fair value of the television reporting unit would decrease by 3%.
Percentage of fair value of assets						19.00%
Television | FCC Licenses and Spectrum Usage Rights
Goodwill [Line Items]
Impairment of goodwill							4,000,000.0
Television | FCC Licenses
Goodwill [Line Items]
Impairment charge related to indefinite life intangible assets					23,500,000
Radio
Goodwill [Line Items]
Goodwill		$ 0				$ 0	0
Radio | FCC Licenses and Spectrum Usage Rights
Goodwill [Line Items]
Impairment of goodwill							$ 200,000
Radio | FCC Licenses
Goodwill [Line Items]
Number of licenses exceeds fair value | License	2
Impairment charge related to indefinite life intangible assets	$ 200,000				$ 8,800,000