Revenues - Summary of Disaggregation of Broadcast Advertising Revenue by Sales Channel (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Disaggregation Of Revenue [Line Items]
Total revenue	$ 197,172	$ 148,880
Advertising
Disaggregation Of Revenue [Line Items]
Total revenue	31,457	33,675
Advertising | Local Direct
Disaggregation Of Revenue [Line Items]
Total revenue	5,421	5,240
Advertising | Local Agency
Disaggregation Of Revenue [Line Items]
Total revenue	12,553	13,188
Advertising | National Agency
Disaggregation Of Revenue [Line Items]
Total revenue	$ 13,483	$ 15,247