REVENUE - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Revenues	$ 1,060,898	$ 1,489,929	$ 1,462,567
Spot revenues
Disaggregation of Revenue [Line Items]
Revenues	705,743	1,092,029	1,099,549
Digital revenues
Disaggregation of Revenue [Line Items]
Revenues	189,988	146,274	119,020
Network revenues
Disaggregation of Revenue [Line Items]
Revenues	80,346	75,629	44,197
Sponsorships and event revenues
Disaggregation of Revenue [Line Items]
Revenues	42,478	102,385	115,846
Other revenues
Disaggregation of Revenue [Line Items]
Revenues	$ 42,343	$ 73,612	$ 83,955