GOODWILL, RADIO BROADCASTING LICENSES AND OTHER INTANGIBLE ASSETS (Details Textual) - USD ($) $ in Thousands	6 Months Ended	9 Months Ended	12 Months Ended
	Jun. 30, 2017	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Schedule Of Goodwill, Radio Broadcasting Licenses And Other Intangible Assets [Line Items]
Pre Tax Impairment Charges			$ 29,100	$ 1,300
Indefinite-Lived License Agreements			614,535	643,449
Amortization of Intangible Assets			26,900	26,200
Impairment Testing [Member]
Schedule Of Goodwill, Radio Broadcasting Licenses And Other Intangible Assets [Line Items]
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)			$ 29,100	1,300
Broadcasting Licenses Valuation [Member]
Schedule Of Goodwill, Radio Broadcasting Licenses And Other Intangible Assets [Line Items]
Indefinite-Lived License Agreements				$ 1,300
2017 Interim Impairment Testing [Member]
Schedule Of Goodwill, Radio Broadcasting Licenses And Other Intangible Assets [Line Items]
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)	$ 12,700	$ 16,400