Segment Information - Disaggregation of Revenue Generating Activities (Details) - 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 operating revenues	$ 493,262	$ 330,857	$ 1,266,368	$ 928,344
Core advertising
Disaggregation of Revenue [Line Items]
Total operating revenues	221,713	210,621	638,275	587,073
Political
Disaggregation of Revenue [Line Items]
Total operating revenues	98,313	5,037	131,749	8,033
Retransmission and carriage
Disaggregation of Revenue [Line Items]
Total operating revenues	153,888	97,128	437,121	277,736
Other
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 19,348	$ 18,071	$ 59,223	$ 55,502