GOODWILL, RADIO BROADCASTING LICENSES AND OTHER INTANGIBLE ASSETS - Additional Information (Details)					3 Months Ended			12 Months Ended
	Oct. 01, 2021 USD ($)	Oct. 01, 2020 USD ($)	Sep. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2020 USD ($)	Sep. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2021 USD ($) segment	Dec. 31, 2020 USD ($)
Schedule of Goodwill, Radio Broadcasting Licenses And Other Intangible Assets [Line Items]
Goodwill, impairment loss								$ 0	$ 15,900,000
Pre-tax impairment charge								0	84,400,000
Indefinite-Lived License Agreements					$ 484,066,000			$ 505,148,000	484,066,000
Number of reportable segments | segment								4
Amortization of Intangible Assets								$ 3,700,000	3,900,000
Impairment charge					$ 1,700,000	$ 29,100,000	$ 53,600,000
Term of radio broadcast station license								8 years
Renewal term of radio broadcast station license								8 years
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
Non Cash Impairment charge		1,700,000
Indefinite-Lived License Agreements								$ 505,200,000
Radio Market Reporting Units [Member]
Schedule of Goodwill, Radio Broadcasting Licenses And Other Intangible Assets [Line Items]
Pre-tax impairment charge	$ 0	$ 0	$ 10,000,000.0	$ 5,900,000		$ 10,000,000.0	$ 5,900,000