Revenues - Summary of Revenues Disaggregated by Major Source (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Disaggregation Of Revenue [Line Items]
Total revenue	$ 148,880	$ 64,249
Broadcast Advertising
Disaggregation Of Revenue [Line Items]
Total revenue	33,675	38,728
Digital Advertising
Disaggregation Of Revenue [Line Items]
Total revenue	101,482	13,331
Spectrum Usage Rights
Disaggregation Of Revenue [Line Items]
Total revenue	2,844	1,356
Retransmission Consent
Disaggregation Of Revenue [Line Items]
Total revenue	9,647	9,580
Other
Disaggregation Of Revenue [Line Items]
Total revenue	$ 1,232	$ 1,254