The Company and Significant Accounting Policies - Additional Information (Detail)			3 Months Ended			12 Months Ended	43 Months Ended
	Mar. 30, 2020 USD ($)	Nov. 30, 2017 USD ($)	Mar. 31, 2021 USD ($) Segment Station Location Market Installment Agreement shares	Jun. 30, 2020	Mar. 31, 2020 USD ($) shares	Dec. 31, 2020 USD ($)	Mar. 31, 2021 USD ($) Location $ / shares shares	Aug. 27, 2019 USD ($)	Apr. 11, 2018 USD ($)	Jul. 13, 2017 USD ($)
Accounting Policies [Line Items]
Number of reportable segments | Segment			3
Percentage of reduction in dividends				50.00%
Percentage of defer the employer portion of social security payroll tax of CARES act			6.20%
Number of installments of deferred employer portion of social security payroll tax of CARES act | Installment			2
Percentage of installment of deferred employer portion of social security payroll tax of CARES act			50.00%
Restricted cash			$ 749,000			$ 749,000	$ 749,000
Retransmission consent revenue			$ 9,600,000
Number of Class A common stock shares converted | shares			1
Shares of dilutive securities not included in computation of diluted earnings per share | shares					659,828
Impairment charge related to indefinite life intangible assets			$ 1,326,000
Impairment charge			1,326,000		$ 39,835,000
Amount approved under share purchase								$ 45,000,000.0	$ 30,000,000.0	$ 15,000,000.0
Aggregate purchase price of repurchased shares					525,000
Unamortized debt issuance costs			1,689,000			1,796,000	1,689,000
Interest income related to available-for-sale securities			140,000		624,000
Assets held for sale			6,138,000			2,141,000	6,138,000
Carrying value of assets			752,168,000		747,345,000	747,345,000	752,168,000
Huston, Texas
Accounting Policies [Line Items]
Agreement amount to sell building	$ 5,400,000
Assets held for sale			200,000				200,000
Laredo, Texas
Accounting Policies [Line Items]
Agreement amount to sell building					2,900,000
Assets held for sale			2,000,000.0				2,000,000.0
Orlando, Florida
Accounting Policies [Line Items]
Impairment charge			1,300,000
Assets held for sale			4,000,000.0				4,000,000.0
Consideration from sale of radio station			4,000,000.0				4,000,000.0
Carrying value of assets			5,300,000				5,300,000
Available-for-Sale Securities
Accounting Policies [Line Items]
Interest income related to available-for-sale securities			$ 100,000
2017 Credit Facility
Accounting Policies [Line Items]
Agreement date		Nov. 30, 2017
Additional borrowing capacity		$ 100,000,000.0
First lien net leverage ratio		4.00%
Certain customary events of default, number of business days to default in the payment of interest on borrowings			3 days
Certain customary events of default, number of days default continue for compliance with other agreement			30 days
Certain customary events of default, number of days default continue for financial statement delivery obligations			10 days
Certain customary events of default, indebtedness aggregate amount			$ 15,000,000.0
Certain customary events of default, failure in payment of final judgments aggregate amount			$ 15,000,000.0
Certain customary events of default, failure in payment of final judgments aggregate amount period			30 days
2017 Credit Facility | Eurodollar Rate
Accounting Policies [Line Items]
Variable interest rate basis spread on debt		2.75%
2017 Credit Facility | Base Rate Margin
Accounting Policies [Line Items]
Variable interest rate basis spread on debt		1.75%
2017 Credit Facility | Term Loan B Facility
Accounting Policies [Line Items]
Senior Secured debt		$ 300,000,000.0
Maturity date of revolving credit facility		Nov. 30, 2024
2013 Credit Facility | Term Loan B Facility
Accounting Policies [Line Items]
Carrying value of term loan			$ 212,800,000				212,800,000
Unamortized debt issuance costs			1,700,000				1,700,000
Estimated fair value of term loan			$ 203,800,000				$ 203,800,000
Class A common stock
Accounting Policies [Line Items]
Amount approved under share purchase								$ 15,000,000.0	$ 15,000,000.0
Number of shares repurchased | shares			0				8,600,000
Aggregate purchase price of repurchased shares							$ 32,200,000
Average price of repurchased shares | $ / shares							$ 3.76
Stock Options And Restricted Stock Units
Accounting Policies [Line Items]
Share-based compensation expenses			$ 1,100,000		800,000
Employee Stock Options
Accounting Policies [Line Items]
Share-based compensation expenses			0		0
Restricted Stock Units
Accounting Policies [Line Items]
Total unrecognized compensation expense related to grants of restricted stock units			$ 4,700,000				$ 4,700,000
Weighted average period for unrecognized compensation expense related to grants of restricted stock units			1 year 7 months 6 days
Univision
Accounting Policies [Line Items]
Payment of sales representation fees to television stations			$ 1,900,000		2,200,000
Number of marketing and sales agreements | Agreement			2
Number of markets involved in sales and marketing | Market			6
Amount due from television stations for carriage			$ 6,500,000				$ 6,500,000
Retransmission consent revenue			$ 6,700,000		7,000,000.0
Common stock percentage held by Univision			11.00%				11.00%
UniMas
Accounting Policies [Line Items]
Affiliate advertising minutes per hour for which entity has right to sell			4 minutes 30 seconds
Accounting Standards Update 2016-18
Accounting Policies [Line Items]
Restricted cash			$ 700,000			700,000	$ 700,000
ASU 2019-12
Accounting Policies [Line Items]
Change in Accounting Principle, Accounting Standards Update, Adoption Date			Jan. 01, 2021				Jan. 01, 2021
Change in Accounting Principle, Accounting Standards Update, Adopted [true false]			true				true
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false]			true				true
Minimum | Employee Stock Options
Accounting Policies [Line Items]
Vesting period			1 year
Minimum | Restricted Stock Units
Accounting Policies [Line Items]
Vesting period			1 year
Minimum | Univision
Accounting Policies [Line Items]
Affiliate advertising minutes per hour for which entity has right to sell			4 minutes
Maximum | Employee Stock Options
Accounting Policies [Line Items]
Vesting period			4 years
Maximum | Restricted Stock Units
Accounting Policies [Line Items]
Vesting period			4 years
Television
Accounting Policies [Line Items]
Number of stations owned | Station			54
Carrying value of assets			$ 434,758,000		425,899,000		$ 434,758,000
Television | FCC Licenses
Accounting Policies [Line Items]
Impairment charge related to indefinite life intangible assets						23,500,000
Radio
Accounting Policies [Line Items]
Number of stations owned | Station			48
Radio operations stations, number of location | Location			16				16
Impairment charge related to indefinite life intangible assets			$ 1,326,000
Carrying value of assets			$ 120,859,000		125,426,000		$ 120,859,000
Radio | FCC Licenses
Accounting Policies [Line Items]
Impairment charge related to indefinite life intangible assets						9,000,000.0
Advertisements and Syndicate Radio Programming | Minimum
Accounting Policies [Line Items]
Number of markets owned | Market			100
Digital
Accounting Policies [Line Items]
Impairment of goodwill						$ 800,000
Carrying value of assets			$ 196,551,000		$ 196,020,000		$ 196,551,000