Revenues - Summary of Revenues Disaggregated by Major Source (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation Of Revenue [Line Items]
Total revenue	$ 68,816	$ 74,575	$ 202,737	$ 215,742
Broadcast Advertising
Disaggregation Of Revenue [Line Items]
Total revenue	37,345	40,183	109,290	119,425
Digital Advertising
Disaggregation Of Revenue [Line Items]
Total revenue	17,612	22,431	48,888	61,233
Spectrum Usage Rights
Disaggregation Of Revenue [Line Items]
Total revenue	2,669	1,178	11,705	1,809
Retransmission Consent
Disaggregation Of Revenue [Line Items]
Total revenue	8,795	8,432	26,641	26,428
Other
Disaggregation Of Revenue [Line Items]
Total revenue	$ 2,395	$ 2,351	$ 6,213	$ 6,847