Revenues - Summary of Revenues Disaggregated by Major Source (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation Of Revenue [Line Items]
Total revenue	$ 62,978	$ 68,816	$ 172,343	$ 202,737
Broadcast Advertising
Disaggregation Of Revenue [Line Items]
Total revenue	37,596	37,345	98,913	109,290
Digital Advertising
Disaggregation Of Revenue [Line Items]
Total revenue	13,655	17,612	38,359	48,888
Spectrum Usage Rights
Disaggregation Of Revenue [Line Items]
Total revenue	1,358	2,669	4,070	11,705
Retransmission Consent
Disaggregation Of Revenue [Line Items]
Total revenue	9,056	8,795	27,998	26,641
Other
Disaggregation Of Revenue [Line Items]
Total revenue	$ 1,313	$ 2,395	$ 3,003	$ 6,213