Revenues - Summary of Revenues Disaggregated by Major Source (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation Of Revenue [Line Items]
Total revenue	$ 69,241	$ 74,329	$ 133,921	$ 141,167
Broadcast Advertising
Disaggregation Of Revenue [Line Items]
Total revenue	37,237	41,533	71,945	79,242
Digital Advertising
Disaggregation Of Revenue [Line Items]
Total revenue	16,804	20,558	31,276	38,802
Spectrum Usage Rights
Disaggregation Of Revenue [Line Items]
Total revenue	3,952	523	9,036	631
Retransmission Consent
Disaggregation Of Revenue [Line Items]
Total revenue	9,086	9,143	17,846	17,996
Other
Disaggregation Of Revenue [Line Items]
Total revenue	$ 2,162	$ 2,572	$ 3,818	$ 4,496