GOODWILL, RADIO BROADCASTING LICENSES AND OTHER INTANGIBLE ASSETS - Digital Segment (Details) - USD ($) $ in Millions	Dec. 31, 2020	Oct. 01, 2020	Dec. 31, 2019	Oct. 01, 2019
Schedule of Goodwill, Radio Broadcasting Licenses And Other Intangible Assets [Line Items]
Pre Tax Impairment Charges	$ 84.4		$ 10.6
Digital Segment [Member]
Schedule of Goodwill, Radio Broadcasting Licenses And Other Intangible Assets [Line Items]
Pre Tax Impairment Charges		$ 0.0		$ 5.8
Discount Rate		14.00%		12.00%
Year 1 Revenue Growth Rate		(5.40%)		12.20%
Digital Segment [Member] | Maximum [Member]
Schedule of Goodwill, Radio Broadcasting Licenses And Other Intangible Assets [Line Items]
Long-term Revenue Growth Rate (Years 6 - 10)				7.70%
Operating Profit Margin Range		13.10%		11.00%
Digital Segment [Member] | Minimum [Member]
Schedule of Goodwill, Radio Broadcasting Licenses And Other Intangible Assets [Line Items]
Long-term Revenue Growth Rate (Years 6 - 10)				2.80%
Operating Profit Margin Range		(12.50%)		(4.70%)