GOODWILL, RADIO BROADCASTING LICENSES AND OTHER INTANGIBLE ASSETS - Valuation of Broadcasting Licenses (Details) - USD ($)					3 Months Ended		12 Months Ended
	Oct. 01, 2021	Oct. 01, 2020	Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020
Schedule of Goodwill, Radio Broadcasting Licenses And Other Intangible Assets [Line Items]
Pre-tax impairment charge							$ 0	$ 84,400,000
Radio Broadcasting Licenses [Member]
Schedule of Goodwill, Radio Broadcasting Licenses And Other Intangible Assets [Line Items]
Pre-tax impairment charge	$ 0	$ 1,700,000	$ 19,100,000	$ 47,700,000	$ 19,100,000	$ 47,700,000		$ 68,500,000
Discount Rate	9.00%	9.00%	9.00%	9.50%	9.00%	9.50%
Radio Broadcasting Licenses [Member] | Minimum
Schedule of Goodwill, Radio Broadcasting Licenses And Other Intangible Assets [Line Items]
Year 1 Market Revenue Growth Rate Range	6.10%	(10.70%)	(10.70%)	(13.30%)	(10.70%)	(13.30%)
Long-term Market Revenue Growth Rate Range (Years 6 - 10)	0.70%	0.70%	0.70%	0.70%	0.70%	0.70%
Mature Market Share Range	6.20%	6.70%	6.70%	6.90%	6.70%	6.90%
Operating Profit Margin Range	26.90%	27.70%	27.70%	27.60%	27.70%	27.60%
Radio Broadcasting Licenses [Member] | Maximum
Schedule of Goodwill, Radio Broadcasting Licenses And Other Intangible Assets [Line Items]
Year 1 Market Revenue Growth Rate Range	8.00%	(16.00%)	(16.80%)		(16.80%)
Long-term Market Revenue Growth Rate Range (Years 6 - 10)	1.00%	1.10%	1.10%	1.10%	1.10%	1.10%
Mature Market Share Range	23.20%	23.90%	23.90%	25.00%	23.90%	25.00%
Operating Profit Margin Range	36.10%	37.10%	37.10%	39.70%	37.10%	39.70%